The Behavior of Moderately and Severely Retarded Persons1

The Behavior of Moderately and Severely Retarded Persons' JOSEPH E. SPRADLIN2 A N D FREDERIC 1. GIRARDEAU3 BUREAU OF CHILD RESEARCH, UNIVERSITY OF

KANSAS,

LAWRENCE, KANSAS

I. Introduction .......................................... 257 11. Respondent Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259 A. Unconditioned Reflex Behavior . . . . . . . . . . . . . . . . . . . 259 B. Conditioned Reflex Behavior . . . . . . . . . . . . . . . . . . . . . . 26 1 111. Operant Behavior ..................................... 262 A. Development of Behavior 262 B. Establishing Stimulus Con 272 C. Shifting Stimulus Control 277 D. Reducing the Frequency o 28 1 E.

Practical Applications of Behavioral Principles in the Development of Adaptive Behavior ................ F. Some Perennial Problems . . . . . . . . . . . . . . . . . . . . . . IV. Conclusion ..... ................................ References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

284 289

294 294

1. INTRODUCTION

The present chapter will discuss the behavior of retardates who score below IQ 50 on a standardized test. Those who score below IQ 25 will be designated as severely retarded. Those who score between 25 and 50 will be designated as moderately retarded. While the definition's of 1 This chapter is primarily concerned with research published since 1960. Articles prior to that date have been included when they are especially relevant to the topic being discussed. T h e writing of this chapter and some of the research reported were partially supported by National Institute of Child Health and Human Development grant HD 00870 01. 2 Field Director, Parsons Research Center. Parsons State Hospital and Training Center, Parsons, Kansas. 8 Field Director, Bureau of Child Research Laboratories, Children's Rehabilitation Unit, University of Kansas Medical Center, Kansas City, Kansas.

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severe and moderate retardation are based on IQ scores, there are rather typical deficits in behavior which are correlated with low IQ scores. Severely retarded persons, especially those in residential centers, most frequently do not dress themselves, are not totally toilet trained, and in many instances do not even feed themselves. Their social reactions to people vary a great deal. Some approach adults in a clinging manner, some pay little attention to adults, and some avoid contact with the adults in their environment. Their interaction with peers and their verbal behavior frequently are quite limited. Some say a few isolated words and phrases but many exhibit no intelligible speech. Their communication with other persons is more often than not limited to crying, screaming, crude gesturing, and tugging at the person as a small child would do. Their responses to the speech of other persons are quite limited, and many do not even respond to their own names. Imitation of children or adults is often extremely limited or nonexistent. Severely retarded persons also exhibit a variety of responses to physical objects in their environment. For example, they may not respond to a toy or they may mouth the toy, attempt to rip it apart, or perhaps throw it. They spend much time engaged in such repetitive behavior as rocking, rolling their heads from one side to the other, flicking their fingers in front of their eyes, masturbating, hand wringing, and thumb-sucking. The category “severe retardation” includes people who exhibit varied behavior; however, the above behavior’s are frequently found among persons labeled severely retarded. Moderately retarded persons frequently are able to dress themselves partially, to take care of most of their own toilet needs, and to feed themselves without assistance. The social reactions of moderately retarded children to adults are somewhat more varied than those of the severely retarded, and they usually exhibit a more extensive verbal repertoire. They are frequently able to imitate rather wide ranges of adult or peer activities. They use toys more nearly like normal children and engage somewhat less frequently in stereotyped activities. In brief, they have a wider range of appropriate behavior (socially defined) which is under the control of both physical and social stimuli. Nevertheless, they fail to meet community norms. They usually do not read, and they speak with poor syntax and articulation. Arithmetic and writing skills are quite limited. Although they may dress themselves, their dress is often substandard or inappropriate. Other types of behavioral deficits which are associated with the labels of moderately and severely retarded could be listed. However, this brief description should suffice to orient the reader to the types of persons being discussed in this chapter. Estimates of the number of severe and moderate retardates range from

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.36 to .50% of the population. If these estimates are correct there is a world population of 10-15 million severe and moderate retardates, including a United States population of approximately 800,000. For clarity of presentation and usefulness to the reader, behavior has been classified into two general categories: (1) respondent behavior; and (2) operant or instrumental behavior. This classification system for behavior is based primarily on procedures used to control the behavior. Respondent behavior is elicited by antecedent events or stimuli (e.g., a light flash, a tap on a tendon). Operant behavior is controlled by its environmental consequences (Skinner, 1938). II. RESPONDENT BEHAVIOR

Respondent behavior refers both to simple reflexive behavior and to behavior developed with a classical (Pavlovian) conditioning procedure. Both unconditioned and conditioned reflexes are included under the label of respondent behavior. Examples of unconditioned reflexes are salivation to food and pupillary contraction to an increase in illumination. To establish a conditioned reflex, a neutral stimulus (e.g., a flash of light which does not elicit salivation) is presented immediately preceding an unconditioned stimulus (e.g., food) which elicits an unconditioned response (e.g., salivation). After some training trials the previously neutral stimulus (now a conditioned stimulus) reliably elicits the conditioned response of salivation. There have been very few studies regarding the respondent behavior of moderately and severely retarded persons. The studies summarized by Lipman (1963) will not be discussed in the present chapter. A. Unconditioned Reflex Behavior

Systematic descriptive studies of the reflexive behavior of moderately and severely retarded persons are noticeably lacking in the literature. The most recent book on the medical aspects of mental retardation (Carter, 1965) does not have an index entry for “reflex” and systematic data regarding reflex behavior for the clinical medical syndromes are scant. General observations that “deep tendon reflexes are sluggish” are reported for some medical syndromes (Carter, 1965). Wall, Umlauf, and Geppert (1964) stated, “Since there are no data available in the pediatric literature on muscle reflex patterns, our initial objective was to determine the feasibility of such testing in the pediatric age group.” Prechtl (1961) has discussed some neurological sequelae of prenatal and paranatal complications. In some babies born in breech presentation, he reported abnormal flexion and extension reflexes of the leg. Another

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abnormality reported by Prechtl was the "hyperexcitability syndrome." After complications which probably included disturbances in oxygen supply, he found infants to be hyperactive and easily startled, with a very low threshold for the Moro reflex. A tremor of low frequency and high amplitude was also reported. Prechtl stated that this "hyperexcitability syndrome" can have serious consequences for the mother-child interaction. Bowers, Gordon, and Segaloff (1959) reported gross observations of the myxedema reflex4 of 11 infants and children. T h e group was composed of six nongoitrous cretins, three goitrous cretins, and two children with hypothyroidism after a thyroidectomy. In all 11 cases the myxedema reflex was strongly present prior to therapy. With therapy, the reflex returned to normal before many of the other clinical signs of cretinism disap peared. Bowers et al., suggested using the Achilles reflex since the muscle is larger and longer and the prolonged relaxation is more readily a p parent. They did not report any quantitative data on the relaxation time, and they pointed out that the force applied to the reflex hammer has an effect on the resulting reflex. With a refined procedure using a Kineometer developed by Lawson (1958), Wall and associates (1964) recorded the free Achilles reflex for 3100 normal children varying in age from 20 minutes to 13 years. Fifty children were studied longitudinally, i.e., muscle reflex patterns were obtained within 24 hr of birth and repeated monthly for 15 months. T h e group data and the individual longitudinal data revealed a reliable, progressive lengthening of the muscle contraction time. The contraction time lengthened from 120 to 182 msec from birth to 13 months and stabilized at 182 msec from 13 months to 13 years. Achilles reflex contraction time for 11 hypothyroid infants and children was lengthened three standard deviations over the normal mean. With eight hyperthyroid patients the muscle contraction time was greatly decreased, i.e., 40 msec or more, faster than three standard deviations from normal. With thyroid treatment, the reflex contraction time of the hypothyroid children returned to normal and correlated we11 with improving cIinica1 status and . . have not seen a laboratory data. These investigators stated they proved case of hypothyroidism that did not have an abnormally slow reflex." Wall, et al. (1964) also studied the Achilles reflex of 276 mongoloid persons, 125 persons with spastic cerebral palsy, and 20 patients with a diagnosis of meningitis. In the mongoloid group, 200 had normal mean

".

4 The myxedema reflex can be elicited from any deep tendon and is characterized by apparently normal contraction of the muscle followed by an abnormally slow reaction time and is typically associated with hypothyroidism.

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contraction times (mean = 191.1 msec), 4 showed typical reflex patterns of hypothyroidism, and 2 had contraction times associated with hyperthyroidism. T h e diagnoses of hypothyroidism and hyperthyroidism, respectively, were confirmed later by laboratory procedures. T h e cerebral palsy group and meningitis group showed similar patterns which included three characteristics: (1) a contraction time in 85% of the cases that was shorter than two standard deviations from the normal mean; (2) a relaxation time that was shorter than the contraction time; and (3) an extremely peaked relaxation phase. McIntire and Dutch (1964) reported that 84 of 86 mongoloids examined by them showed generalized hypotonia which was manifested in all the major muscle groups. Th e hypotonia was best demonstrated when the muscle was in the resting state. B. Conditioned Reflex Behavior

According to C . M. Franks (1964), the literature regarding classical conditioning with retardates is sparse, especially in the languages of Western Europe. There are also very few studies reported in the American literature. Razran (1961) reviewed several studies from the Russian literature and apparently the “new look” in conditioning is semantic conditioning studies of the type done by Luria and his associates. According to the classification system used in this chapter, many of these are instrumental, or operant, rather than classical conditioning. C. M. Franks (1964) reported that the conclusions regarding respondent conditioning are conflicting for retardates in general. Cromwell, Park, and Foshee (1961), using retardates with an IQ range of 15-68, found n o relationship between IQ and eyelid conditionability.6 Behrens and Ellis (1962) found simultaneous eyelid conditioning to be superior with retardates, when compared with normals. There were no differences between normals and defectives with a trace conditioning procedure. There is fair agreement, according to C. M. Franks (1964), ‘‘. . . that congenital idiots form conditioned responses with great difficulty if at all (Franks, V., 1959).” In reporting a recent series of studies, C. M. Franks (1964) pointed out that conditionability is related, not to intellectual differences, but to neurological differences as far as the conditioned eye blink is concerned. Brain-damaged retardates conditioned significantly more poorly than nonbrain-damaged Ss whereas nonbrain-damaged normals and retardates conditioned and extinguished equally well. 5 Whether the eyeblink response is a respondent or operant escape response which is learned at an extremely early age is open to question. However, in this chapter it will be discussed as respondent behavior.

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Grings, Lockhart, and Dameron (1962) reported that moderately retarded Ss conditioned as well as mildly retarded Ss. The usual optimal interval of .5 sec between conditioned stimulus (CS) and the unconditioned stimulus (US) was not found by these investigators. and they reported that a 5-sec interval was as efficient as the .Bsec interval. Baumeister, Beedle, and Urquhart (1964) found no evidence for differences in Galvanic skin response conditioning between a group of normals and a group of retardates with a mean IQ of 49. Differences in conditioning as a function of CS-US interval were reported, but there was no evidence for an interaction between intelligence level and CS-US interval. It is rather clear that data are limited regarding the unconditioned and conditioned reflexive behavior of moderately and severely retarded persons. 111. OPERANT BEHAVIOR

A. Development of Behavior

Operant behavior is behavior which is initially brought under control by its consequences. The behavior is not elicited (as is respondent behavior); instead, once it is emitted, it operates on, or changes, the environment. It is instrumental in producing a consequence and frequently is labeled instrumental behavior. In contrast to respondent behavior, no eliciting stimulus can be specified for operant behavior. One can, however, arrange the environment so that the response is likely to be emitted. Once the response is emitted, it is reinforced thus increasing the probability that similar responses will occur in the future. Reinforcement refers to a stimulus change which results in an increase in the frequency of the class of behavior on which it is contingent. Reinforcement may be either positive or negative. Positive reinforcement refers to the presentation of a stimulus which increases the frequency of a response. The presentation is contingent on the response. Positive reinforcers, in general, refer to those events which people describe as rewarding, pleasant, desirable, and are often referred to as “goals” or “incentives.” For example, presentation of candy to a child who has just said, “I’m hungry,” will increase the frequency of “I’m hungry” responses under similar conditions in the future. The prompt comfort and attention of an adult to a child who makes loud cries when slightly injured may increase both the frequency of loud cries and mild injuries. This is even more probable if the child does not receive attention and comfort on other occasions. Negative reinforcement refers to the increase in the withdrawal of an aversive stimulus as a consequence of the subject’s response. The with-

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drawal is contingent on the response. Negative reinforcers (or aversive stimuli) refer to those events which people describe as unpleasant or noxious. They are frequently spoken of as things to avoid. For example, a child’s finger gets caught in a door or drawer and he calls for his mother. If his mother comes, releases the finger, and there is a subsequent reduction in pain, then on future occasions when his finger is caught, he will probably call for his mother. Two common examples of behavior developed by negative reinforcement are the covering of the ears when loud noises are presented and going into a warm house following periods of exposure to extremely low temperature. Many everyday situations include both positive and negative reinforcement procedures, and they certainly can be combined in a laboratory or practical application situation. The behavior of a child, who comes in from the cold during the winter and is given a piece of cake, is maintained by both positive reinforcement (cake) and negative reinforcement (escape from cold). For the mother who has several young children, the hiring of a babysitter so that she may go bowling may involve both positive and negative reinforcement. Not only is she praised for her bowling skills but her behavior terminates aversive stimulation arising from the simultaneous care of several children (e.g., screaming, nagging, etc.). If one is having trouble establishing a response, such as sitting in a chair, using positive reinforcement, the process might be speeded up by adding negative reinforcement to the procedure. This can be done by having a loud noise present in the room when the child enters. Sitting in the chair terminates (withdraws) the negative reinforcer (loud noise) and results in the presentation of a positive reinforcer (candy). Such a procedure is probably more effective than either reinforcer alone, providing the aversive stimulus is not sufficient to elicit strong emotional responses such as crying, screaming, and refusing to enter the room. 1. TYPES OF REINFORCERS

One of the first steps in the modification of behavior is the determination of an effective reinforcer. Most of the earlier operant studies of severely and moderately retarded children used nutritive or unconditioned reinforcers. Fuller (1949), used warm milk delivered by a syringe to condition a nonambulatory, untestable 18-year-old male to raise his right arm, Even earlier, Mateer (1918), who interpreted her work in terms of Pavlovian conditioning, reported that she had conditioned anticipatory mouth opening, using bits of sweet chocolate and sweetened water. Sweet chocolate (M & M’s) has become one of the favorite reinforcers for use with moderately and severely retarded persons (Bijou & Orlando, 1961; Ellis, Barnett, & Pryer, 1960; Orlando & Bijou, 1960; Spradlin, Girardeau.

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& Corte, 1966). While M & M’s are reinforcing for many retardates, there

are some for whom they are not. This same comment, however, could be made about any other single nutritive. For this reason, some experimenters use a mixture of candies and other nutrients as reinforcers (Bijou & Orlando, 1961; Orlando & Bijou, 1960; Spradlin et al., 1966). The use of a mixture of nutrients has the advantage of increasing the chances that an effective reinforcer will be included. However, it has a disadvantage. While the feeder delivers something on a specified schedule, the S may be reinforced on some very different schedule. For example, suppose the equipment is wired to deliver a reinforcer after every 25 responses (FR-25). An equal mixture of four types of candy is used. Suppose further that the S rejects two of the four types of candy. I n this case, the effective schedule is not a simple FR-25, but presentation of the conditioned reinforcers (houselight dim, relay click, etc.) on an FR-25 schedule and presentation of the effective food reinforcer on a variable ratio 50 (VR-50) schedule. In other words, every 50 responses (on the average) is followed by a reinforcer which the S consumes. For a short term study involving few reinforcements, it is possible to simply present various foods to a child until you find one which reinforces. This is a fairly easy discrimination for the E . If the S eats the food, smiles and reaches, begs, or sticks out his tongue for more, you probably have an effective reinforcer. Hollis (1962) used a limited version of the above procedure to select a reinforcer for use in training severely and moderately retarded persons to work a bent-wire problem. Hollis offered each S Coca-Cola or mints and used the one which the S responded to more appropriately. This procedure was generally effective; however, there were Ss for whom this procedure (or reinforcement selection) was inadequate. Watson, Lawson, and Sanders (1965) studied the edible (candy and food) and manipulable (movies, sounds, mechanical toys) reinforcement preferences of 14 moderately and severely retarded children (mean CA = 11-0 years and mean IQ = 23). Ss were given poker chips which could be exchanged for any one of five types of candy or the operation of a tape recorder, movie projector and screen, or any one of five mechanical toys. One poker chip would produce either a piece of candy or 10 sec of music, viewing a movie, or movement by a mechanical toy. Initially there was a preference for the manipulables but, over 13 sessions, there was no evidence for a difference between the two classes of reinforcers. Among the manipulables, music was preferred significantly more than the other six alternatives. Spradlin et al. (1966) compared six types of food reinforcers (grapes, maraschino cherries, corn chips, cheese sticks, M & M’s, and mints) for

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five severely retarded Ss. Each S received five 20-min sessions on FR-25 with each food. As a group, these Ss did not show food preferences; however, it should be remembered that the fixed-ratio schedule is a powerful, controlling schedule which is not affected greatly by moderate variations in amount of reinforcement. Moreover, variability in deprivation might mask any type of reinforcement effect. Most of the studies using nutrients as reinforcers have not controlled deprivation or have used extremely mild deprivation puller (1949) used 15 hr]. Spradlin et al. (1966) studied the effects of mild deprivation (17 hr) on the response frequency of three severely retarded boys. Frequency of response increased for two of the Ss but did not for a third S until the reinforcement was shifted from corn chips to M & M’s. Work has been conducted at Parsons with two severely retarded children who, when they received their meals in the regular dining hall, would make few, if any, responses for candy, milk, and other nutrients.6 However, these Ss would respond for prolonged periods of time when the major portion of their daily diet was obtained by performing in the experimental setting. The first S was simply given her regular diet of milk, potatoes, meat, etc., in the experimental setting. The S performed rather well for regular food. However, regular food has two major disadvantages: (1) it is not easily dispensed; and (2) more importantly, the caloric intake per meal is difficult to determine. Furthermore, there is no way to insure a balanced diet. In order to overcome these problems, Metrecal cookies and liquid were substituted for the regular meal and vitamin supplements were given. The first S was shifted to Metrecal. The second S was started on Metrecal at the beginning of the experiment. For the first few meals both Ss were somewhat slow in responding to Metrecal. With one S a Wisconsin General Test Apparatus (WGTA) was used in presenting a variety of stimuli. In this situation, the E delivered either one-fourth of a Metrecal cookie (6+ calories) or about one-fourth ounce of liquid Metrecal (7 calories) per correct response. The S lost some weight on this regimen at first but then maintained a high rate of performance and a stable weight condition for over 3 months on this diet. A second S was in a typical operant conditioning setup in which she pressed a key in the wall for reinforcement. Initially, one-fourth of a Metrecal cookie was delivered to her; however, performance remained low and she ate very few cookies unless she was periodically given liquid. After several sessions, she was shifted to a moist mixture of Metrecal liquid and crushed cookies 6 This work has been conducted by John Hollis, Research Associate, at Parsons Research Center; John Kane, Research Trainee at Parsons Research Center; and the first author, 1965.

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(1 oz liquid to nine cookies). These were mixed in the morning, rolled into small balls, and placed in the refrigerator 2-8 hr before using. These Metrecal balls were rather easily dispensed by a Gerbrands Universal Feeder with only an occasional ball sticking to the feeder. This problem was totally solved by making sure a period of 4-6 hr elapsed during refrigeration of the balls. As was the case with the first S, there was an initial slight loss in weight. However, the S ate the Metrecal balls well and responded for periods of time up to 3 hr per day. Interestingly, when the Ss were taken off Metrecal and placed on a regular diet, they went back to eating the regular diet immediately. Moreover, after several days on regular meals they would eat Metrecal even when satiated with food from their regular diet. One S, on a regular diet, frequently walks off the cottage and goes to the experimental room where Metrecal is delivered. Moreover, when this S was placed in a hearing experiment where Metrecal was used as a reinforcer, she responded well on Metrecal balls. She was on ad lib regular food. Apparently the taste for Merrecal can be acquired. Baer, Peterson, and Sherman (1965) used the children’s regular meals as reinforcement in developing discriminated imitative behavior by three moderately and severely retarded children. The meal was delivered a spoonful at a time by the experimenter, contingent on imitative behavior by the child. Other reinforcers have been suggested and used with severely retarded children. For example, Hollis (1965~)found that performance on a bentwire problem could be maintained for some Ss by social reinforcement (gentle pat on the head and a verbal statement, “Good girl, Susie”). Meyerson and Michael (1960) have worked with vibratory stimulation as a reinforcer for severely retarded persons. Petre7 is exploring the use of battery-operated toys as reinforcers for some children. The toy is remotely operated for 10 sec when a correct response is made in a matching-to-sample reading readiness program. One particular S who rejected candy and trinkets performed at a much higher rate for the movement of the mechanical toy. Several researchers have used generalized conditioned reinforcers in operant studies with human Ss. A generalized conditioned reinforcer is a discriminative stimulus which sets the occasion wherein responding will yield any one of several types of reinforcers (e.g., food, water, toys, termination of an aversive condition, etc.). Money is a prime example of a 7 Information of this study was obtained through personal communication with Richard Petre, Research Associate, Bureau of Child Research Laboratories, University of Kansas Medical Center, Kansas City, Kansas. 1965.

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generalized conditioned reinforcer and has been used in a variety of human operant studies (Lindsley, 1964; Schwitzgebel & Schwitzgebel, 1961; Slack, 1960). Tokens have been used by researchers dealing with retarded persons (Ayllon & Azrin, 1965; Birnbrauer & Lawler, 1964; Girardeau &. Spradlin, 1964; Heard, 1964; Watson, Lawson & Sanders, 1965). These tokens are redeemable for such merchandise as trinkets, toys, candy, fruit, articles of apparel, pop music, etc. They are established as reinforcers rather quickly even with moderately and severely retarded children (Girardeau & Spradlin, 1964; Watson et al., 1965). I n general, tokens have been used primarily in executing rather gross demonstrations of procedures based on operant techniques; however, work has been done by Hom and Kanes using tokens as reinforcers for studying schedule effects with moderately retarded children. These tokens show extremely powerful control over the behavior of moderately retarded children in the laboratory situation. Still other persons (Heard, 1964; Long, Hammack, May, & Campbell, 1958; Meyerson & Michael, 1960) have used a mixture of trinkets as reinforcers in various kinds of operant experiments using normal and retarded children as Ss. Using a mixture of trinkets is subject to the same criticism as the use of a mixture of foods; however, most of these writers report that trinkets, or trinkets and candy, maintained behavior quite well. Social consequences also have been used in operant and instrumental studies with retarded persons (Barnett, Pryer & Ellis, 1959; Hollis, 1965a; Hollis, 1965b; Locke, 1962). Harris, Wolf, and Baer (1964) have demonstrated that the attention of certain adults can serve as a n effective reinforcer for several types of behavior emitted by nursery school children. Although such systematic studies have not been done with the moderately retarded, the implications of the Harris et al., work are that social reinforcers can be powerful with selected children particularly in an institution where adult attention is not often gained by the child. Our casual observations indicate that its effects with severely retarded children are quite unpredictable. This is not to say that social reinforcers will not work with some severely retarded children. Rather, they will work only with selected children and, even then, their effects may be limited or unpredictable. Social comments have limited value as reinforcers due to the fact that they depend so much on the unique history of the child. If a n adult’s comments have, in the past, set the occasion where responses were reinforced, it is quite likely that comments by adults now will be rein8 Information of these studies was obtained through personal communication with George Horn and John Kane, Research Trainees at Parsons Research Center. 1965.

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forcing, at least for a while. However, if such comments have not been positively backed up or have been associated with aversive conditions, it is quite likely that they will have either no effect or an aversive effect. Thus, comments by adults can be neutral or conditioned aversive stimuli. There have been a few systematic studies of the effects of the termination of an aversive stimulus on the behavior of moderately or severely retarded children. However, Lovaas, Freitag, Kinder, Rubinstein, Schaeffer, and Simmon (1964) has reported on the use of an aversive electrical stimulus with behaviorally limited autistic children. Lovaas’ procedure involved placing the autistic child in a small room with electrical grids. Two adults were in the room with the child. Initially, when the electricity was turned on, one adult pushed the child into the arms of the other adult. The child thus escaped the electrical stimulation. After relatively few shocks, the child was shaped to sit on the adult’s lap and hug, touch his cheeks, etc. This behavior extinguished when shock was discontinued for long periods of time; however, one noncontingent shock was enough to reestablish the behavior. Ward0 brought the behavior of a severely retarded mongoloid child under the control of an intense auditory stimulus. The S had been shaped previously to pull a knob using positive reinforcement. Then white noise which could be terminated by pulling the knob was introduced. Moreover, each response delayed the onset of white noise a specified amount of time, 5 sec, 10 sec, or 15 sec. Highly reliable escape behavior developed. However, the child did not learn to avoid the stimulus. The experiment was terminated due to the development of emotional behavior by the S.

2. SCHEDULES OF REINFORCEMENT A reinforcer may be delivered following every response; such a schedule is usually termed continuous reinforcement (CRF) or fixed ratio 1 (FR-1). Reinforcers also may be delivered intermittently. When a reinforcer is delivered after a predetermined number of responses have been emitted, the term “fixed ratio” (FR) schedule is used. “Fixed interval” (FI) shedule is the term used when a reinforcer is delivered for the first response following a fixed time interval. When a reinforcer is delivered following a variable number of responses (e.g., on the average every 10 responses but varying between 1 and 20), the term “variable ratio” (VR) is used. The term “variable interval” (VI) schedule describes a procedure in which the reinforcer is delivered following a response after varying time intervals. “DRL” refers to a schedule in which low rates of responding are rein9 Information concerning this study was obtained through personal communication with James Ward, Research Trainee at Parsons Research Center. 1964.

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forced but not high rates, i.e., differential reinforcement of low rate. A discussion of other schedules can be found in Ferster and Skinner (1957). Ellis et al. (1960) studied the fixed ratio behavior of 12 adult Negro males with IQs less than 30. These 12 Ss were selected from a total of 22 Ss. The other 10 Ss were excluded from the major part of the study because they failed to respond, cried, wanted out, or responded only when told to do so. Later, informal study of the 10 who were excluded indicated that all but 3 or 4 could be trained to respond and adapt to the situation. The behavior studied was responding on a Lindsley manipulandum. The Lindsley manipulandum consists of a knob which, when pulled, trips a microswitch so that the response may be recorded. The Ss were seen for 30 sessions. M & M's were used as reinforcers and a 5-sec time-out period (in which the goal box light was on and the house light was off) occurred with the delivery of each reinforcer. Ss were on FR-10 for 11 days. Then they were shifted successively to FR-SO, VI-1, FI-1, FR-10, and to FR-100. Each session lasted 30 min. Ss exhibited quite varied behavior under all schedules. Under the fixed ratio schedules, most Ss exhibited high rates; however, at least one S exhibited low rate behavior and finally ceased responding. On the variable interval schedule the rates for 3 of the 4 SS, whose cumulative records were presented, were high. The rate of the fourth was quite low. Scalloping on FI-1 appeared infrequently. In general, Ss did not show typical FI low rates. However, it should be remembered that Ss had been on ratio schedules previously and were on interval schedules for only a few hours at most. In a subsequent study reported in the same article, Ellis et al. (1960) studied the fixed ratio behavior of 26 teenage and adult Negro males with IQs between 30 and 70. The Ss were switched from a candy reinforcer to cigarettes on the twelfth day. There were more pauses in responding by the lower mental age Ss but behavior was maintained quite well for most Ss on fixed ratio schedules as high as 1024. Orlando and Bijou (1960) studied the effects of single and multiple schedules on the behavior of retarded children with IQs between 23 and 64 who ranged in age from 9 to 21 years. They used Hershyettes, candy corn, M & M's, and mints as reinforcers. The response was pressing the handle from the squeezer of an O'Cedar mop. A small bulb high over the reward box was dimmed for 3 sec as a conditioned reinforcer. Sessions lasted from 15 to 60 min and were typically scheduled twice each week, Orlando and Bijou studied VR, FR, VI, FI, and DRL schedules. FR schedules of 10-25 and VR schedules of 100 generated high stable rates of behavior. VR schedules yielded fewer and aperiodic pauses, while FR schedules yielded pauses primarily after reinforcement before the beginning of a run. Orlando and Bijou report that VI schedules yielded rates

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which were quite like those obtained by VR schedules with the exception of greater amounts of course grain. The results under FI conditions were the most variable. Some Ss emitted “runaway” rates similar to those obtained under VR and FR conditioners, while others emitted paced rates. However, with additional sessions most Ss adopted low rates with an occasional scallop. Headrick (1963) studied the effects of instructions on the behavior of 24 retarded persons (IQ range = 31-76, mean IQ = 51) on FI schedules. The experimental setting and apparatus were similar to that reported by Ellis et al. (1960). Four types of instructions were given. Nine Ss were told to pull the knob and reinforced on an FR-1 for 3-8 responses or on an FI-.5 for a while, then shifted to an FI-2 schedule. Seven of the nine Ss in this group emitted high-rate response patterns; only two emitted low rates. Nine Ss were told simply that they could get some pennies, candy, or cigarettes and started immediately on an FI-2 schedule. Only one S in this group emitted a high-rate pattern; the other eight emitted low rates with some scalloping. Three Ss were told to pull the knob and started immediately on FI-2. Two of the Ss had high-rate patterns and one a moderate rate pattern. Three Ss were instructed that they could get candy, pennies, or cigarettes. They were reinforced for eight responses on FR-1, and then shifted to FI-2. Two of the three Ss emitted high-rate patterns and one a low-rate pattern. In summary, Headrick’s data indicate that the rate of responding one obtains on fixed interval schedules is a function of instructions and experience on previous schedules. Spradlin et al. (1966) studied the effects of FR and FI schedules on the behavior of severely and moderately retarded children. The basic procedures were also quite similar to the Ellis et al. (1960) procedures. They found that under FR schedules, most of the Ss developed high rates of responding, with pausing confined primarily to periods right after reinforcement. Once an S began to respond, he rarely stopped before completing the ratio. When Ss were placed on FI schedules for about 10 hr, their rates were low but only two of six Ss on these schedules showed distinct scalloping. Kane’o has studied the behavior of two moderately retarded girls on DRL schedules (schedules in which a certain amount of time must pass since the S’s last response for a response to be reinforced). Kane used tokens backed up by merchandise as reinforcers. The schedules used have been DRL 20 sec and DRL 45 sec. On DRL schedules the rates were quite low as expected. One S on DRL 20 sec showed short bursts of responding during the first 5 sec after reinforcement. Responses showed a sharp drop 10

Personal communication. 1964: see Footnote 9.

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during the next 5 sec and then gradually increased during successive 5-sec periods through the 15-sec to 19-sec interval. Then-there was a decrease of responding. The other S overshot DRL 20 sec most of the time; in other words, she did not respond until after the 20 sec had passed. When put on a DRL 45 sec this S undershot and showed a pattern similar to the first S on DRL 20 sec. Kane found that when he increased the amount of spring tension on the manipulandum, both Ss showed a decrease in responses immediately after reinforcement and a general increase in efficiency. However, when tension was set low, the Ss undershot to a greater degree than the baseline. In general, observations of the girls’ performance on DRL schedules were interesting. An S might repeatedly exhibit certain chains, such as pulling the manipulandum, looking in the goal box, walking to the opposite side of the room, tapping the wall and then slowly walking back to the panel and pulling the manipulandum again. Kane and Spradlin studied two severely retarded children on short variable interval schedules, VI-10 sec. The reinforcers were Metrecal balls (as described in the section on types of reinforcers). One S developed steady moderate-rate responding on this schedule while a second S developed extremely low rates which looked more like the behavior usually obtained by DRL schedules. These low rates were maintained on the VI-10 sec schedule in spite of the fact that the S received all of her daily food intake in the experimental session during the time she was on a VI-10 sec schedule and her weight was reduced to approximately 93% of normal. During the long pauses (approximately 30 sec after reinforcement) the S would engage in stereotyped behavior almost continually. It seems quite likely that a long superstitious chain of behavior was being reinforced. Later, a 5-sec limited hold was placed on the VI-10 sec schedule. (That is, if the S did not respond within 5 sec after reinforcement became available, she simply missed that reinforcement.) This resulted in more responses; however, it did not totally eliminate long pauses after reinforcement. When the limited hold was reduced to 1 sec, local rates went even higher; however, there were still long pauses after reinforcement. Horn11 studied the effect of amount of reinforcement on responses made by moderately retarded Ss on a concurrent schedule. Tokens were used as reinforcers. During baseline sessions, both responses were reinforced on an independent VI-2 schedule. The reinforcement on each schedule was two tokens until responses on each manipulandum were stable. Reinforcement was then shifted so that response to manipulandum 1 paid off one token on a VI-2 schedule while responses to manipulandum 2 paid off 11

Personal communication. 1964: see Footnote 9.

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three tokens on a VI-2schedule. Amount of reinforcement showed initial clear-cut effects on time spent and number of responses made on each manipulandum. However, with further sessions the difference became much less stable. That is, amount of reinforcement had a strong initial effect on preference; however, the behavior became unstable with additional sessions.

3. OTHERREINFORCEMENT VARIABLES Within the past 3 decades latency of reinforcement and amount of

reinforcement have been studied extensively at several phyletic levels. I n general, these studies have shown that immediate reinforcement is much more effective in developing behavior than delayed reinforcement and that larger amounts of reinforcement (within limits) are more effective than smaller amounts. These variables have not been studied systematically with moderately and severely retarded persons. However, beginning efforts have been made by Ellis (1962) and Hom’s study reported above. 4. CHANGES IN REINFORCER VALUES It is quite important to point out that (1) what serves as a reinforcer at one time might not be effective at another time, and (2) what will serve as a reinforcer for one person might not be effectivewith a different person. The first point is most clearly illustrated by the fact that food will serve as a reinforcer for a deprived person but not for a satiated one. Physical contact might be a reinforcer on some occasions but not on other occasions. Regarding the second point, one should be aware that what might be positively reinforcing for one child could be aversive to another. In working with moderately and severely retarded persons, both points are important. These are two major reasons why generalized conditioned reinforcers (such as tokens, money, etc.) are useful when one is working with the retarded for extended periods.

B.

Establishing Stimulus Control (Discrimination)

Stimulus control means that an organism responds differently when a given stimulus is present than when it is absent or that the organism responds differently to one stimulus in its environment than i t does to another. DISCRIMINATION 1. FREEOPERANT The traditional method of establishing stimulus control over a single operant in a free operant experiment has been first to increase the rate of the responding in the presence of the positive stimulus (SD) through

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positive reinforcement and then simply to extinguish the response during the time when the negative stimulus (SA) is present and the SD is absent. This procedure can be used to establish discrimination with some moderately and severely retarded persons, However, the procedure will not inevitably lead to discrimination. The present writers ran one severely retarded child for over 200 sessions. When the S was placed in the room, the houselight was off as was a white noise generator. The S was never reinforced until the houselight and noise generator were turned on. At the end of the session the houselight and noise generator were turned off and the S was no longer reinforced. This S continued to respond both prior to the onset of the noise and light and after the noise and light had been turned off at the end of the session. In short, he did not learn the discrimination. This is in marked contrast to a moderately retarded adolescent boy who came under control of both the light and the noise. This S, who was on an FR-75 schedule, came to respond only when the light and noise were on. If, during the final sessions, either the light or noise were terminated, the S stopped responding immediately and did not respond again until the light and noise were again both present. This was true whether the light or tone was off 20 sec or 10 min. In fact, stimulus control was so precise that the casual observer might speculate that knob pulling was elicited rather than operant behavior. The failure to discriminate in a free operant situation is not totally unique to severely retarded persons. Sidman (1960) reports that when the presentation of the SD is made on a time schedule independent of the S’s behavior, failure to discriminate frequently occurs. He attributes this to superstitious chaining due to the adventitious reinforcement of responding during the SA period by the presentation of SD. He suggests that one can preclude this problem by making the presentation of the SD contingent on a second kind of response during SA. Thus, during SA the S makes one response to present the SD and, once the S D occurs, the S makes a second response to obtain the reinforcer. One may also overcome superstitious chaining in discrimination learning by making presentation of the S D contingent on a fixed time interval of not responding during the SA. Bijou and Orlando (1961) have used a modified form of this procedure in developing discrimination by moderately retarded children. Bijou and Orlando first established a specified rate of responding in the presence of the SD by reinforcing the response on an FR-1 schedule-then they introduced the SA. The S D was then presented again whenever the S paused for a specified amount of time. After pauses of this amount of time were occurring quickly during the SA, the pause time was increased. The pause time was gradually increased until the S was pausing for 30 sec during the SA period. During the next

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phase, the Ss were placed on either a ratio or temporal intermittent schedule with times or ratios gradually being increased to either an FR-50 or an FI-1 min schedule during the SD period. This procedure resulted in rather precise multiple schedule discrimination by eight moderately retarded children with IQ’s between 30 and 42. The above described procedures for establishing discrimination in a single response free operant situation are traditional. That is, they rely on strengthening the response during the SD period and extinguishing it during the SA period. There has been much speculation that this is the only way that discrimination can be learned (Keller & Schoenfeld, 1950). However, Terrace (1963a) has recently reported data on pigeons which lead to questioning such assumptions. Terrace, by presenting the SA for short periods of time when the pigeon was not in a position to respond, was able to establish a high rate of responding to the SD and almost no responses to the SA. In other words, the S did not go through an extinction process with the SA. These procedures have not been investigated with severely retarded persons but they would seem to hold promise. Barrett and Lindsley (1962) have investigated discrimination in an experimental situation where two stimulus patterns and two responses are available to the Ss. Their Ss were retardates whose IQs ranged from 33 to 72. They used candy and pennies as reinforcers. The contingencies involved FR-10 reinforcement for the left manipulandum when the light above i t was on. When the light over the left knob went off, the light over the right knob was presented. No reinforcement was delivered for any response on the right knob, and responses on the left were reinforced on an FR-10 schedule only when the light was on above it. Barrett and Lindsley reported a variety of behavior. Some Ss showed neither discrimination nor differentiation. That is, they pulled either knob equally often regardless of which light was on. Other Ss learned to discriminate the light on-light off condition, but overgeneralized the response to the nonreinforced knob. One S developed both discrimination and differentiation but correct performance went down during subsequent sessions. Orlando (1961) ran two moderately retarded adolescents (IQ 34-40) on a two-choice operant discrimination task. The operant chamber included two response panels spaced four feet apart, separated by a chute for delivering reinforcers (small pieces of candy). On each panel there was a Lindsley plunger-type manipulandum with two stimulus lights (red and blue) mounted above it. For each S one of the stimulus lights was designated the SA and the other the S D . For example, when SD occurred on one panel, SA was occurring on the other. The SD and SA shifted from one panel to the other after a short interval. Correct responses were designated as those which were made on the panel with the SD, while errors were

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responses made on the panel with the SA. During the interval session, SS were reinforced on a VR-25 schedule for correct responses until they reached a correct response rate of 20 responses per min, then they were shifted to a VR-100 for correct responses. The criterion for discrimination was 90% correct response for a 32-min session. During the six sessions following realization of the criterion, each S received two 4-min tests for positive-cue (SD) removal, negative cue (SA) removal, and reinforcement removal. One test of 4 min was given per session. These tests were given in a counterbalanced order in the 20-40-min interval of each session. Removal of reinforcement for 4 min showed no effect on discrimination. One S’s percentage of correct responses dropped from 99.7 to 56.5 when the S D was removed but showed no decrement when the SA was removed. The other S dropped from 99.1 to 32.4 when the S A was removed but showed little loss when the SD was removed. The data indicate that either S D or SA may control responding and the effective controlling stimulus may vary from S to S. Investigations have been initiated by Spradlin and Kane to develop the free operant discrimination of severely retarded children. The initial attempts to develop discrimination involved a multiple FI-1:FR-50 schedule. The FI-1:FR-50 schedule involved a single manipulandum. When one stimulus light was on, reinforcement was delivered on an FR-50 schedule. When the other light was on, reinforcement was delivered on an FI-1 schedule. None of the three severely retarded Ss showed any evidence of discrimination under these conditions, nor did they when the multiple schedule was shifted to FR-50:extinction. More recently, Spradlin and Kane have been using a two-manipulanda situation. With one severely retarded S, plastic keys on the panel were used as the manipulanda. Responses to a key resulted in reinforcement only if a red light behind it was on. When the light behind one key was off, the light behind the other was on. Prior to discrimination training, the S had been on a variable interval 10-secschedule with a limited hold of 1 sec. During initial discrimination training, the S was on this same schedule whenever she was responding on the lighted key. Responses to the unlighted key were never reinforced. After approximately 15 hr of training on this schedule, the S made very few errors (i.e., less than 57, of her responses were to unlighted keys). However, when the S was shifted from this two-response discrimination situation to a single response discrimination, she responded both to the right key (key which was lighted part of time, S D ) and to the left key which was now unlighted (extinction) at times when the right key was off. Discrimination on the right key broke down as a function of no alternative correct response. However, after 21 hr the S was making few responses to the unlighted left key and less

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than 5% errors on the unlighted right key. In other words, this severely retarded child had formed nearly perfect discrimination. After seeing the relative ease with which discrimination was established with this severely retarded child with a two-response system, the Es attempted a two-response discrimination with one of the previous Ss who had failed to discriminate on a one-response system. This S was a severely retarded adolescent male with a left temporal lobectomy. The simple tworesponse discrimination procedure was not adequate to establish discrimination by this S, so a variety of techniques were used in an attempt to establish discrimination. The last technique used involved turning off the houselights and making the stimulus light flicker in an attempt to control observing responses. This technique was only partially successful insofar as the S continued to make about 20% errors (i.e., responded to the unlighted stimulus).

2. EXPERIMENTER-PACED DISCRIMINATION The most frequent type of discrimination studied with moderately and severely retarded children has been multi-choice simultaneous discrimination (Stevenson, 1963; Zeaman & House, 1963). This type of discrimination usually is a two-choice one in which a positive stimulus (SD) and a negative stimulus (SA) are presented to the S simultaneously. If the S responds to the positive stimulus, he is reinforced; otherwise, he may be allowed to make a second response (correction procedure) or both stimuli may be removed and set up for the next trial (noncorrection procedure). Unlike the free operant situation, the arrangement of the physical environment by the experimenter usually precludes the S from making a response except at specified times called trials. Zeaman and House (1963), as well as others, have used the simultaneous procedure for studying the effects of pretraining variables and stimulus variables on the performance of moderately retarded persons. Seventeen retarded Ss (IQ range = 30-68, mean IQ = 49) were given three trials on each of 64 two-choice visual discrimination problems by Zeaman, Thaller, and House (1964). Half the problems had a constant irrelevant dimension and half had a variable irrelevant dimension. Superior performance was found on the problems with the constant irrelevant dimension. Eimas (1964) studied the visual discrimination learning of retardates (IQ range = 38-67, mean IQ = 49) as a function of compound and component cues. Performance was attributed to the utilization of both “types” of cues, and the statement was made that retarded children appear to be able to utilize a considerable amount of the stimulus information provided.

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Ellis, Girardeau, and Pryer (1962) investigated the development of learning sets by severely retarded adolescents and young adults (IQs less than 25). The task involved learning a series of “junk-type” two-choice simultaneous discrimination tasks with a noncorrection procedure. Ss were reinforced with a mixture of reinforcers such as grapes, M & M’s, crackers, etc. Ten Ss showed no improvement over 200 problems. Ten Ss achieved near perfect performance by the 17th day (98% correct) and 10 Ss achieved roughly 75% correct responses. This study indicates that some severely retarded persons are able to learn a simple simultaneous discrimination and, second, that for some Ss, performance on this task improves with successive training on a series of discrimination problems. C. Shifting Stimulus Control

While it is sometimes necessary to establish a new or basic discrimination, this is frequently not the case. Often behavior is already under stimulus control; the problem is how to bring the behavior under the control of other stimuli. Terrace (1963b) studied three ways of shifting stimulus control from one SD to a second SD in a fixed trial experiment. Pigeons had been trained by errorless discrimination techniques to respond when the red light S D appeared. The pigeons were then shifted to a discrimination situation in which a vertical line was the SD and a horizontal line was the SA. Three procedures for shifting were used. The first technique (abrupt shift) involved an abrupt shift from the red-green discrimination to the vertical horizontal discrimination. This procedure appeared no more effective than if he had never learned the initial discrimination. The second technique (superimposition only) involved superimposing the vertical line on the red key and the horizontal line on the green key for five 60-trial sessions and then presenting the horizontal and vertical lines above. This procedure was superior to the abrupt shift procedure. The third procedure, superimposition and fading, involved superimposing the vertical line on the red key and the horizontal line on the green key for five sessions, and then during the following session, the red and green light were progressively diminished until only the vertical and horizontal lines remained. This procedure resulted in a shift in discrimination without errors. After Ss reached criterion for learning the vertical-horizontal discrimination, they were shifted back to the red-green discrimination. Ss who had only the abrupt shift and the superimposition treatments now made errors on the original discrimination, while the Ss receiving the superimposition and fading treatment did not. Meyerson and Michael (1960) reported a fading procedure for establish-

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ing tone control over responding in a two-manipulanda operant situation. Their Ss were moderately retarded children on whom they were attempting audiometric evaluation. Their experimental situation included a Dalrymple panel with two Lindsley manipulanda. Above each manipulandum was a stimulus light. They found that there was a high probability of an S responding to the manipulandum if the light above it was on. Thus, they first established a twu-response light discrimination through reinforcement of responses to the manipulandum with the light on above it. Then they paired the tone-on stimulus with the light under one manipulandum and tone-off with the light on under the other manipulandum. They, then, gradually faded the light. Soon their Ss were responding to one manipulandum when the tone was on and to the other manipulandum when the tone was off. This allowed for an evaluation of hearing. Gove, Lawson, and Watson (1964) have found that moderately and severely retarded children, who did not exhibit differential responding when a single four inch black disc was used as an SD and its absence as an SA, did respond differently when the black disc was associated with a bright white background light as the SD condition and a tone plus a dim blue background light as the SA condition. Once stimulus control was well established, the extra stimuli could be gradually withdrawn until only the presentation of the black disc controlled responding. Sidman12 has used the procedure of gradually changing the controlling SD, while gradually introducing SA stimuli in a multiple choice discrimination task, to train a severely retarded microcephalic adult to make rather fine discriminations between a circle and an elipse. A second general situation where the shifting of stimulus control is useful is in teaching the person to make the same response in the presence of several different stimuli. A good example is the shift from saying “car” in the presence of the object to saying “car” in the presence of a picture of a car and finally in the presence of the printed word. A study by Hermelin (O’Connor & Hermelin, 1963) demonstrated that the control over a verbal response could be shifted rather rapidly from a picture to a word when the Ss were 10 moderately retarded children. His treatment was somewhat analogous to Terrace’s superimposition only treatment. Four words-“bed,” “corn,” “dog,” and “cup”-were taught individually. The procedure was as follows. The S was asked to tell the experimenter what was on the card each time it was presented on a screen. All correct responses were rewarded with a sweet plus the verbal response “good.” The picture was presented first. When the S had named it cor12 Personal communication with Dr. Murray Sidman, Neurology Research, The Massachusetts General Hospital, Boston, Massachusetts. 1964.

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rectly on five consecutive trials, the word and picture were presented simultaneously. When these had been named five times correctly the word alone was presented and five correct naming responses were required. When this criterion had been reached, the card with the word and picture was withdrawn and an additional five consecutive correct responses to both the picture and the word was required. This same procedure was followed with the remaining three words. It took an average of 4.7 presentations to reach criterion on the first word, 1.9 for the second, 1.3 for the third, and 1.1 for the fourth. Each of the four words was then presented with two similar ones and the S had to select the correct word. Trials were repeated until the correct word was selected on 10 consecutive trials. It took 10.7 trials to reach criterion on the first word discrimination, 1.4 for the second, 1.8 for the third, and 2.8 for the fourth. Finally the S was presented the four learned words on cards and was asked to name each card for three trials. The average number of errors out of a possible 12 was 2.6. O’Conner and Hermelin (1963) reported a study which illustrates the process of gradually shifting the control of a response from one stimulus to other stimuli. Their Ss were 24 moderately retarded children between 9 and 15 years of age with IQs below 40. Experimental and control Ss were matched on the basis of IQ. The experimental task was that of training Ss to recognize four words“panda,” “horse,” “fish,” and “swan.” For the experimental group, the following treatment was applied. One of the words, such as “horse,” was selected for training. This “cue” word was presented in large print (10 mm letters) on a card along with three cards on which the three other words appeared in small print (3 mm letters). The S was shown a picture of a horse and asked to name it. Then he was asked to select the card with the word horse. If the S responded correctly, he was given a reward. If not, he was told which printed word was correct. Then the four cards were again rearranged and the procedure repeated until the S made 10 consecutive correct responses. This ended the first stage. In successive trial stages the size of the correct word was gradually reduced in five additional stages from 10 mm to 8 mm, to 6 mm, to 5 mm, to 4 mm, and finally to 3 mm. The same training procedure was used successively for the remaining three words. The control group received the same treatment except that the cue word was always the same size as the other three words (3 mm). The Ss receiving the experimental treatment learned to recognize the words in significantly less trials than did the control group. Retention tests yielded no significant differences between experimental and control

ss.

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1. IMITATION Imitation is a class of behavior under the control of stimuli which result from another person’s behavior and has been studied within the framework of discriminated operant behavior. The occasion for reinforcement is simply that s’s behavior matches the other person’s behavior. Bandura and Walters (1963) have pointed out the importance of imitative behavior in the development of social behavior in human Ss. However, these authors did not specify how imitative behavior develops. Recently, Baer et al. (1965) have demonstrated that imitative behavior by severely retarded children can be established using reinforcement procedures. Baer, et al. (1965) observed several severely retarded children extensively for several days and found no spontaneous imitation. An E then engaged them in play and asked them to imitate some simple responses he demonstrated. Imitative behavior did not occur. The subsequent training procedure involved telling the child, “Do this,” giving a demonstration, and following the s’s response with food reinforcement. With the S who had the most extensive training, 130 discriminated operants were taught using food as the reinforcer. Physical assistance by the experimenter was used at first to get the imitative behavior started. During the training program, generalized imitation occurred, i.e., responses were imitated the first time they were presented. Several of these were not reinforced by E but remained strong (although never reinforced) when they were included with imitations that were reinforced. Chains of imitative behavior of a rather complex nature were developed. Furthermore, new behavior could be included in the chain and they were imitated. With one S at least, the imitative behavior also generalized to new Es. Another important aspect of the study was the development of verbal imitation whereby one S was slowly taught 10 usable words. Finally, an extinction procedure resulted in greatly decreased imitative performance, but the behavior was reinstated by reinstating the contingent reinforcement. Metz (1964) has reported the use of a similar procedure in establishing generalized imitative behavior with two autistic children. The results of these studies hold a great deal of promise for the training of severely retarded persons. 2. GENERALIZATION Any discussion of discrimination involves generalization. I n fact, witho u t generalization the gradual shift of stimulus control discussed above would not occur. Lane and Curran (1963) studied auditory loudness gradients of three moderately retarded blind children. The reinforcer

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used with al! three Ss was 3 sec of recorded music. One S was given twomanipulanda training. He was trained to press the left button when a low intensity (56 db) 500 cps tone was presented. He was trained to press the right button when a high intensity (76 db) 500 cps tone was presented. The other two Ss were given single-manipulandum training. They were trained to respond to a 74-db tone but not to a 56-db tone. All Ss were given 10 test presentations at each of 11 loudness intensities ranging from 50 to 80 db. Reliable generalization gradients were obtained with both the one-manipulandum and the two-manipulanda procedures. Gradients were asymmetric and nonmonotonic. D. Reducing the Frequency of Behavior 1. EXTINCTION

Extinction refers to a decrease in performance as a function of withholding or discontinuing reinforcement. Extinction processes have been widely studied with animals. However, studies of extinction with human Ss have been limited primarily to short term group studies. Moreover, most of these studies have investigated only the initial phases of extinction due to reliance on a rather arbitrary criterion for extinction. For example, Spradlin (1962) used as a criterion for extinction, 30 sec without a response. Spradlin did find, however, that 24 intermittently reinforced responses led to a greater number of responses during extinction than did 24 continuously reinforced responses, when moderately retarded children were Ss. Moreover, most Ss reached criterion for extinction within the first 10 min after reinforcement was discontinued. This finding is in line with the results of both human and animal extinction studies. Ellis (1962) studied the effect of amount of reinforcement on time and number of responses to extinction. The Ss of his first experiment were retarded persons with I@ ranging between 11 and 80 with a mean IQ of 46.2. The reinforcers were cigarettes. Twenty reinforcements were programmed according to an increasing ratio of 1, 4, 8, 12, 16, 32, 48, 64, 96, and 128 for the last 10 reinforcements. If an S completed the acquisition phase, he made 1585 responses for 20 reinforcements. Two different amounts of reinforcement were used-three cigarettes and one cigarette. There were no significant differences between groups in reaching criterion for extinction (10 min without a response or leaving the room). However, responses to extinction, time to extinction, and responses during conditioning all showed an absolute difference in favor of the low reinforcement group. I n a second experiment, Ellis studied extinction with 56 institutionalized severely retarded males between 8 and 27 years of age. The pro-

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cedure was the same as the first study except that the ratios were 1, 4, 12, 16, 24, 32, 40, 48, 56, and 64 for the last 10 reinforcements. Cigarettes and penny candy were used as reinforcement. There was no significant effect as a function of amount of reinforcement. However, absolute differences in extinction time and responses to extinction were in the opposite direction from the first study. In both studies a majority of the Ss reached criterion for extinction. In summary, the studies yielded no evidence that amount of reinforcement had a significant effect on performance during extinction. Hollis studied the effects of extinction on the bent-wire performance of a single severely retarded child over several experimental sessions. Prior to extinction the child was given either a bite of Metrecal cookie or a drink of Metrecal liquid after each correct response. For several sessions the S had made 40 correct responses in 40 trials. The S was then fed prior to the session and no more food was given during the session. After four sessions of extinction under satiation conditions, the S’s correct responses went to near zero. When the S was not fed prior to the session and reinforcement was delivered, performance recovered completely. Later Hollis ran extinction series of 40 trials under deprivation conditions and fed the S after the fortieth trial. Performance remained quite high. I t seems likely that this procedure is somewhat like reinforcing behavior on an FR-40. I n an earlier study Hollis (1965~)studied the bent-wire performance of severely and moderately retarded children under nutrient reinforcement and extinction. In general, performance was decreased under both social reinforcement and extinction conditions. However, this was not true for all Ss. Fuller (1949) increased the frequency of arm raising by a “vegetative human organism” from .67 to 3 responses per min by delivering warm milk as a consequence. Extinction occurred when Fuller quit delivering milk. The results of the above studies indicated that complete elimination of reinforcement did result in a reduction of performance, that intermittent reinforcement led to greater resistance to extinction than did continuous reinforcement, and that resistance to extinction was not significantly affected by varying amounts of reinforcement within limited ranges. 2. PUNISHMENT Research and training efforts with moderately and severely retarded children have been spasmodic and unsystematic. Only in the last 10 years have researchers begun to consider the moderately or severely retarded an adequate S for behavioral research. Thus, it is not surprising that vast gaps exist in experimental research on behavioral processes

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with such Ss. One area of investigation which has been especially neglected with retarded Ss, is punishment. The control of retarded persons’ behavior with aversive techniques is generally in disrepute among professional psychologists today. This is especially true concerning the use of punishment, e.g., making the delivery of an aversive stimulus contingent on a response. I t is true that aversive techniques have been applied quite ineffectively in the past. Moreover, the widely publicized studies of Estes (1944) seem to indicate that punishment is ineffective in eliminating behavor. However, the recent animal data on punishment, as well as everyday observations, suggest that punishment should be given a more careful analysis before concluding that it is ineffective as a procedure for modifying the behavior of retarded persons. Researchers at Anna State Hospital have analyzed the effects of punishment on both human and animal &. The results of their work indicate the following. 1. Mild and moderate punishment (shock or intense noise) have little effect on the rate of responding if there is no alternate response which will deliver reinforcement (Azrin, 1960; Herman & Azrin, 1964). 2. Severe punishment will suppress a response totally and for long periods of time (Holz & Azrin, 1963). 3. When severe shock is administered, its results may be nonspecific. That is, the pigeon does not peck the key, but may also not eat grain when presented (Holz & Azrin, 1963). 4. Mild punishment will result in a marked decrease in responses if it serves as an SA. That is, it sets the occasion when a response is not reinforced (Holz & Azrin, 1961; Holz & Azrin, 1962). 5. Punishment will increase the frequency of responding if it sets the occasion for reinforcement. That is, pigeons will peck a key when they are shocked on each response if the shock indicates that grain will be forthcoming (Holz & Azrin, 1961; Holz & Azrin, 1962). 6. Even mild punishment is effective in reducing the frequency of behavior if an alternative response is available which will deliver the same reinforcer (Herman & Azrin, 1964). Some questions for further research with retarded children suggested by this literature are the following. 1. Does punishment reduce the frequency of a reinforced response if no alternative response will obtain reinforcement? 2. Does it make a difference whether punishment is applied early or late in acquisition? 3. Can punishment be established as an SD for responding if it sets the occasion for reinforcement?

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4. Is punishment effective in reducing the frequency of responses by retarded children if an alternative response is available? 5. What kinds of stimuli are effective as punishment? Lovaas et al. (1964) has reported preliminary work using shock to eliminate self-destructive behavior. The presentation of a painful stimulus (electric shock) was contingent on the self-destructive behavior of two autistic children. The behavior was suppressed within minutes and remained so for 11 months. When it reoccurred, a single noncontingent shock resuppressed the behavior for the remainder of the study. Previous attempts to use noise as a punishing stimulus had proved unsuccessful in reducing the self-destructive behavior. The following conclusions can be drawn from the experimental literature concerning moderately and severely retarded persons. 1. Both moderately and severely retarded persons do learn under appropriate reinforcement conditions. 2. Food is a n effective reinforcer for most moderately and severely retarded persons. This is especially true if the S is on dietary control. 3. Music, movement of mechanical toys, vibrations, and social contact are effective reinforcers for some moderately and severely retarded persons. 4. Tokens can be established as powerful generalized reinforcers for moderately and severely retarded persons. 5. The behavior of both moderately and severely retarded children can be brought under stimulus control in the experimental laboratory. 6. Stimulus control may be established by making SD and SA conditions quite different, by presentation of SD only after a short pause in responding on SA, or by providing an alternative reinforced response during the time that one response is under S A conditions. 7. Stimulus control is most likely to be shifted from an SD to another stimulus if the change in stimulus conditions is made gradually rather than abruptly. 8. The behavior of moderately and severely retarded persons decreases in frequency if it is not reinforced. However, this decrease may not be immediate. This is especially true if the behavior has been maintained on an intermittent schedule. 9. Experimental work on the effects of punishment on the behavior of moderately and severely retarded children is extremely limited.

E.

Practical Applications of Behavioral Principles in the Development of Adaptive Behavior

There are admittedly great gaps in the laboratory operant research with mentally retarded persons and other human Ss. These should be

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filled. However, many persons feel that treatment programs need not wait until all of the principles established on lower animals have been tested with human Ss in laboratory situations. Moreover, early reports by persons who have applied these principles to treatment problems seem to uphold this opinion (Staats, 1965; Ullmann & Krasner, 1965). The results to date indicate that operant principles are amenable to application in everyday situations. With relatively few principles, one can make changes in the behavior of moderately and severely retarded persons. 1. PERSONAL SELF-CARE SKILLS The lack of simple self-care skills is a major problem of severely retarded children. The development of the motor requirements for such skills can be established through shaping (reinforcing successive approximations of the desired behavior). Numerous investigators (Bensberg, Colwell, & Cassel, 1965; Blackwood,, 1962; Hundziak & Maurer, 1963; Pursley & Hamilton, 1965; Spradlin, 1964) have reported success in training severely retarded persons to feed themselves. Self-feeding, once established, generally maintains itself since it is continuously reinforced in the natural environment. The general procedure for training self-feeding involves partial support by a trainer at first. The trainer assists by helping the retarded person fill his spoon and then helping him move it toward the mouth. The person then makes the last part of the movement himself. The trainer then reduces the assistance in very small steps (fades the stimulus control) until the retarded person is finally making the entire chain of behavior himself. The procedure, including the carrying of trays, is described in more detail by Spradlin (1964). Food throwing, if it occurs, can be eliminated by reducing the amount of food served and providing a time-out period as a consequence of the behavior. The training of dressing behavior has been reported by Bensberg et al. (1965). Each step of dressing was evaluated and ranked from least difficult to most difficult. Beginning with the most simple step, sequences were developed and food rewards were given following successful completion of each step. As training progressed, more and more was required of the person before he was reinforced. In the last stages, they were required to completely dress before receiving a reward. The program was begun with simple clothing and new, more difficult clothing was introduced gradually with appropriate training. Perhaps it should be mentioned here that the development of motor skills, such as dressing, can probably be assisted by changes in the materials ordinarily used by average persons. In other words, planning

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for the retarded should probably include changes in the physical environment as well as the shaping of behavior. For example, in terms of training dressing behavior, simpler clothes could be used a t first. Changes to ordinary clothing could be made in small steps, if the wearing of ordinary clothes is the desired behavior. Lindsley (1964) has discussed the development of prosthetic environments for these children. Michael (1963) and Ellis (1964) also have discussed certain changes in the physical environment which should improve the retardate’s interaction with his environment. Gove et al. (1964) have designed a commode which might prove quite useful in shaping toilet behavior. Toilet training of moderately and severely retarded persons has been attempted by Bensberg et al. (1965), Blackwood (1962), Dayan (1964), and Hundziak, Maurer, and Watson (1963). Blackwood (1962) and Hundziak et al. (1963) were able to shape toilet behavior but were unable to maintain it when rewards were withdrawn. These investigators speculate that the behavior was not under appropriate stimulus control. I n other words, the toilet behavior was under the control of the attendant’s telling the child or leading him to the bathroom rather than under the control of a full bowel or bladder. Bensberg et al. (1965) and Dayan (1963) report success with a behavioral approach described by Ellis (1963). Bathing, teeth brushing, hair combing, hair setting, ironing, mopping, cutting fingernails, proper sitting, and other skills have been taught with the same procedures (Bensberg et al. 1965; Girardeau & Spradlin, 1964). Wolf, Risley, and Mees (1964) trained a moderately retarded autistic child to wear glasses and reduced such undesirable behavior as temper tantrums through the systematic application of operant techniques. Once these skills are developed using a positive reinforcer delivered after nearly every response, the behavior can be maintained by requiring more and more responses before a reinforcer is given. Social reinforcers can then be used to maintain the behavior for many children. 2. SOCIALSKILLS Operant principles have not only been useful in the development of motor skills of a self-care nature, but also appear quite promising when applied systematically in programs designed to develop social and educational skills. Moreover, the acquisition of personal skills leads to increased opportunity for social behavior to occur and be reinforced. T h e child who is relatively clean and properly dressed is more likely to be responded to by adults. Thus, there are more opportunities for the child to be reinforced socially. I n fact, the development of rudimentary self-

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care skills is probably a prerequisite for the development of social and educational skills. Ayllon and Michael (1959) were among the first to suggest the systemitic application of behavioral principles to ward management and the training of groups of behaviorally deficient persons. Although their work, as well as the subsequent programs reported by Ayllon and Haughton (1962) and Ayllon and Azrin (1964), was primarily with adult schizophrenics, the general procedures which they used have proven to be effective with moderately and severely retarded persons. Birnbrauer and Lawler (1964) have reported work with a class of moderately and severely retarded children in an educational setting. In this study, operant principles were used to establish social and studying behavior of 37 moderately retarded children (all below IQ 40). By positively reinforcing approximations to desirable social and studying behavior, extinguishing inappropriate and incorrect behavior, and punishing dangerous behavior, these children were able to accomplish a great deal in one year. With four exceptions, they learned to hang up their coats upon entering the classroom, take their seats quietly, and wait for their assignments with only an occasional reminder. Eleven advanced to the point of working persistently on programmed multiplechoice prereading assignments which required from 10 to 30 min to complete. Candy (M & M’s) was used at first as a reinforcer, but there was a systematic shift to poker chips. Plans were reported to shift the reinforcers to grades and social approval as quickly as possible. Also, a classroom for moderately and mildly retarded children has been operated by Birnbrauer, Bijou, Wolf, and Kidder (1965). A beginning effort has been made at Parsons State Hospital and Training Center in the development of a comprehensive program designed to train moderately retarded children to live adequately in their home community (Girardeau & Spradlin, 1964). A cottage of 28 adolescent girls (IQ range = 20-50) was selected and two 21-year-old girls were hired as additional personnel. After a gross evaluation period, bronze tokens approximately the size of a half-dollar were established as generalized conditioned reinforcers by allowing the girls to trade them for candy, fruit, cosmetics, soda pop, lace underwear and numerous other articles. In addition to purchasing items with the tokens, there were rental materials available, such as watches, record players and records, bicycles, and transistor radios. After about 10 days a shaping procedure was introduced, i.e., the girls were required to make slight improvements in their behavior before tokens were given to them. One of the most immediate problems was

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that of devising constructive activities for these girls. Pets (goldfish, parakeet, turtles) were introduced on the cottage, and the girls were taught how to care for pets. The rewarding of self-care activities was a major part of the program for the first year but many other activities were included in the program. The activities listed in Table I are illustrative of the variety of skills which are being developed. The elimination of undesirable behavior is being accomplished primarily TABLE I A SAMPLE OF THE BEHAVIORS WHICH ARE REWARDED A N D APPROXIMATE REWARDAMUUNTS Behavior Making u p bed Dressing for meal Brushing teeth Taking shower properly Helping clean cottage Setting hair Straightening bed drawer Trimming and filing nails Combing hair Washing hair Group play (30 min) Coloring Work placement in institution Cleaning goldfish bowl Feeding goldfish Cleaning bird cage School readiness tasks Being on time at work or speech therapy Shining shoes General proper use of leisure time (20-min period)

Approximate reward amount 1 token 2 tokens 2 tokens 2 tokens Quite variable 4 tokens 2 tokens 2 tokens 1 token 2 tokens 5 tokens Quite variable 10 tokens/day 5 tokens 1 token 5 tokens Quite variable 4 tokens 5 tokens 4 tokens

by using an extinction procedure (e.g., totally ignoring tantrum behavior) and by rewarding behavior which is incompatible with the undesirable or maladaptive behavior. When it has been necessary to reduce the frequency of behavior quickly, a combination of mild punishment (time out from earning tokens) of the undesirable behavior and reward for other desirable behavior has been used. Gross observations indicate that desirable behavior is increasing in frequency and that undesirable behavior is decreasing in frequency.

3. VERBALSKILIS One of the frequently cited problems of the moderately and severely

retarded is the lack of verbal behavior or an impoverished verbal repertoire. Schiefelbusch (1965) has pointed out some of the essential aspects involved in the development of language by the retarded.

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For the child without any communicable vocal behavior, the first step might be to train him to respond vocally to a vocalization of the trainer by the procedure used by Kerr, Meyerson, and Michael (1965) with a retarded three-year-old girl of approximate IQ 25. Initially, the child was reinforced for any vocalization and then the requirements were gradually increased. Later in the study, the child was reinforced for vocalizations only if they occurred within 5 sec of the trainer’s vocalization. Echoic behavior (matching the experimenter’s vocalization) was not required. As Kerr et al. (1965) point out, a shaping procedure could probably be used throughout but it is highly impractical and time consuming. The procedure in the usual environment probably involves a great deal of echoic behavior. In the imitation study by Baer et al. (1965) a child was given 10 words through imitative training. These were echoic, i.e., the controlling stimulus was the sound made by the experimenter. Following echoic training, control of the vocalizations of retarded children can be shifted to objects and pictures (Risley, 1965). Heard (1964) trained four moderately retarded children to recognize and respond phonically to letters of the alphabet with diacritical marks. His procedure involved a variety of verbal training including establishing an echoic response, shifting the response from echoic to textual control, and pointing out matching symbols in a matching-to-sample task. He used social comments and tokens redeemable in edibles and toys as reinforcers. Heard’s techniques and accomplishments are too complex for an adequate review in this chapter. However, the person interested in teaching reading will find many suggestions concerning techniques in Heard’s dissertation. Petrel3 is developing a program for the training of concept formation by language impaired children. This program can be used by the moderately and severely retarded, as well as the deaf, aphasics, etc. The procedure is a matching-to-sample one in which a word (e.g. hat) is presented and several pictures of different hats are presented below the word. On different trials the child is reinforced for responding to different hats. In this manner the child learns to respond to different hats in the presence of the same word, hat.

F.

Some Perennial Problems

Much of the behavior of the moderately and severely retarded is aversive to many people. Other prevalent behavior, though not aversive, is incompatible with the development of adaptive behavior. There have 18

Personal communication. 1965: see Footnote 8.

1. E . Spradlin and F. L. Girardeau been few systematic attempts to solve such problems as self-destructive behavior, stereotypies, tantrums, aggressive behavior, drooling and nasal discharge, excessive clinging to others, abnormalities of posture (including sitting), and excessive masturbation. The following remarks regarding some perennial problems are, for the most part, speculative. However, the principles used in the speculations are based on research with both children and lower animals. 1. INSTITUTIONAL MALADAPTIVE BEHAVIOR

There is some maladaptive behavior which is typically found in institutions. This behavior is developed and maintained by the institutional environment. For example, the institutional environment provides very little adult attention for the child. However, when the child has a tantrum, is aggressive with others, breaks a window, or exhibits self-destructive behavior, he usually receives a great deal of attention from the attendant and professional personnel. Probably the most effective procedure for reducing the frequency of these behaviors is to withhold reinforcement when they occur, i.e. extinguish them. However, in a field situation if one withholds reinforcement for one undesirable response, the person may make an even more objectionable response which cannot be ignored. For example, if adult attention is withheld when a tantrum occurs, then aggressive behavior toward the adult may occur. If this goes unreinforced, then selfdestructive behavior may develop which forces the adult to reinforce by giving attention. Thus, prior to the initiation of extinction for maladaptive behavior, the retarded person should be given the reinforcer for adaptive responses. When selfdestructive behavior occurs, it is often possible to handle the situation adequately and not provide some of the usual adult attention of a positive nature that customarily accompanies such a situation. Pursley and Hamilton (1965) have described a typical situation and suggested an appropriate procedure for the personnel involved. Lovaas, Freitag, Gold, and Kassorla (1965) have been interested in self-destructive behavior and have reported work using shock to eliminate self-destructive behavior. The presentation of a painful stimulus (electric shock) was contingent on the selfdestructive behavior of two children. The behavior was suppressed within minutes and remained so for 11 months. When it reoccurred, a single noncontingent shock resuppressed the behavior for the remainder of the study. T h e present writers would speculate that the punishment would be most effective if the self-

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destructive child were reinforced for behavior incompatible with selfdestruction. Clinging or hugging of both friends and strangers is a behavior which is exhibited in high frequency in institutions for retarded persons. Yet this kind of behavior is generally unacceptable in a community and might even reduce the probability of weekend visits home if the child embarrasses the parents by clinging to neighbors or visitors. This behavior is not an innate characteristic of retarded persons but is generated by the social reinforcements of an institutional environment. The persons in the institutional environment are apt to overlook a retarded person if the person is playing with blocks, drawing, or merely talking to them in a conversational voice. However, it is most difficult to overlook a patient who is clinging to you. Moreover, most visitors of an institution have no particular behavior goal for the child other than to make him smile for the moment. Thus, even though clinging is temporarily mildly aversive, they socially reinforce it by talking to the child and perhaps even hugging the child in return. If asked why they don't ignore the child or push him away they usually respond that they do not want him to "feel rejected." Yet they are reinforcing the exact behavior which will preclude acceptance by a normal peer or adult. Clinging can be reduced rather quickly with no bad side effects if the personnel and visitors are instructed to ignore clinging and to direct attention to the child while he is not clinging. Moreover, if social or verbal 'reinforcement of other behavior (such as walking beside a person without clinging) does not reduce the clinging then reinforcers such as tokens, candy, and money may be used initially to establish nonclinging behavior. Poor posture is a characteristic which quickly identifies many institutionalized retarded children as different from their peers in the community. Correct posture can be developed by reinforcing approximations to the desired posture and ignoring deviations from the desired behavior. Such a procedure is being used in the cottage program reported by Girardeau and Spradlin (1964). 2. AGGRESSIVE BEHAVIOR Aggressive behavior may be under the control of numerous variables. First, aggressive behavior may be a positively reinforced operant. When a child obtains another child's toy, food, or other reinforcers by striking, biting, or kicking, such behavior is reinforced by positive consequences. Moreover, a child who obtains little adult attention may be reinforced by adult attention when he is aggressive toward another child. It is not unusual for the aggressor to be taken aside by the adult and asked why he hits other children, asked to resolve to do better in the future, and

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finally assured he is loved. Such a procedure may be a powerful reinforcer for the child who infrequently receives adult attention on other occasions. Aggressive behavior may also be reinforced by the termination of an aversive situation. For example, counter-aggressionmay terminate another child’s hair pulling, biting, or pinching. Bandura and Walters (1963) have found that normal children will imitate the aggressive behavior of peers and adults. Thus aggression may occur as a form of generalized imitation. Finally, research on animals (Ulrich & Azrin, 1962) suggests that certain forms of aggression or attack may be pain-induced. That is, presentation of a painful stimulus such as shock and intense heat will result in attacks on other organisms. Such pain-produced aggressive responses are short lived in white rats and usually stop immediately after the painful stimulus is terminated; however, with monkeys these aggressive responses are vicious and will continue even after the termination of the painful stimulus. There is no scientific evidence for pain-produced aggression in human Ss. However, the phenomenon is so widespread among lower species and seem so in line with casual observations that it seem likely that it does occur with the human organism. The procedures for reduction of aggressive behavior by retarded children necessitates the analysis of the variables controlling the behavior. If aggressive bkhavior is being maintained by positive reinforcement, one can reduce such behavior simply by changing the contingencies so that aggressive behavior goes unreinforced while nonaggressive behavior is reinforced. Close supervision may prevent the aggressive child from profiting from striking, kicking, or biting. That is, if he uses these devices to take a toy, the toy i s immediately taken from him. However, if he makes some sort of nonaggressive request the supervisor would be very quick to provide the toy or one which is similar. Counter-aggression or aggression which terminates an aversive consequence may not present a problem unless the counter-aggressive responses become too severe, In this case one may have to reduce counteraggression by controlling the initial aggressive responses of the other person. Counter-aggression may be closely related to pain-produced aggressions and thus may be very difficult to reduce through control of the consequence variables. Finally, one may reduce aggressive behavior by providing nonaggressive adult and peer models. Numerous investigators have reported that a large percentage (over 50%) of institutionalized moderately and severely retarded persons exhibit stereotopies (Berkson & Davenport, 1962; Hollis, 1965b; Kaufman

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& Levitt, 1965). These stereotopies include such repetitive acts as body swaying, head rolling, and flicking the fingers in front of the eyes. Kaufman and Levitt (1965) found that head rolling and body swaying occurred more frequently right before lunch and at 3:OO p.m. when the attendant shifts changed. Levitt and Kaufman (1965) found that rocking increased with increased intensities of white noise. Davenport and Berkson (1963) and Hollis (1965a; Hollis, 1965b) has found that availability of objects reduced stereotyped behavior. The present writers would speculate that rocking and head rolling are superstitious behavior developed in an impoverished environment in which reinforcement is noncontingent. Rocking and head rolling are responses which occur with high frequency among normal persons; however, they are usually under very tight stimulus control. For example, normal persons rock in rocking chairs and turn their heads back and forth in looking for objects or in following conversation. When a child has no toys, objects, or other controlling stimuli, head rolling and rocking are no doubt probable. Suppose that while the child is rocking he is called to lunch, to a bus ride, or any one of several noncontingent reinforcers. The probability that he will rock or head roll the next time he is hungry, thirsty, or bored is now higher. The increased stereotyped behavior now increases the probability that reinforcement will occur during the time the person is stereotyping. Under such conditions stereotyping may become extremely frequent and persistent. If rocking and head rolling are superstitious behavior they could be reduced in frequency by arranging the environment so that reinforcements are delivered primarily when the patient is engaged in behavior which is incompatible with stereotyping. Excessive and indiscreet masturbation is a problem which often perplexes those who manage retarded persons. It is unlikely that masturbation can be completely eliminated. However, one may reduce the frequency of masturbation in public by providing the person privacy. Moreover, the general frequency of masturbation may be decreased by reinforcing activities that are incompatible with masturbation. The use of a handkerchief or tissue in handling excess saliva or nasal discharge is a skill which moderately and severely retarded children often lack. We have found several techniques useful in eliminating this problem. First, the child was provided with an apron in which to keep tissues. Then an adult would demonstrate how to use the tissue or might possibly move the child’s hand with the tissue so that the nose or mouth was cleaned. During the early stages the child was given a token (reinforced) for cleaning her nose or mouth even if it was with help. Later a token was given if the child used the tissue without help and sometimes merely

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for having a clean mouth or face. Gradually the support of the adult and the frequency of reinforcement was reduced. IV. CONCLUSION

The last portion of this chapter has been devoted to the solution of practical problems through the use of operant techniques. In cases where operant techniques have been applied, the reported results are encouraging. One might hope that these advances would lead to the development of training and educational programs which one day would allow these persons to live in and contribute to the noninstitutional community. The extent to which such a goal is accomplished depends primarily on the ingenuity and effort of interested workers. The present writers believe that if the principles and techniques discussed in this chapter were consistently applied, Butterfield’s (1961) case of overachievement by a mongoloid might be considered “typical” rather than a “provocative case.” REFERENCES Ayllon, T., & Azrin, N. H. Reinforcement and instructions with mental patients. J . exp. anal. Behav., 1964, 7 , 327-331. Ayllon, T., & Azrin, N. H. The measurement and reinforcement of behavior of psychotics. J . ex$. anal. Behav., 1965, 8, 357-383. Ayllon, T., & Haughton, E. Control of the behavior of schizophrenic patients by food. I. exp. anal. Behav., 1962, 5, 343-352. Ayllon, T., & Michael, J. L. The psychiatric nurse as a behavioral engineer. J . exp. anal. Behav., 1959, 2. 323-334. Azrin, N. H. Effects of punishment intensity during variable-interval reinforcement. J . exp. anal. Behau., 1960, 3, 123-142. Baer, D. M., Peterson, R. F., & Sherman, J. A. Building an imitative repertoire by programming similarity between child and model as discriminative for reinforcement. Read at biennial meeting of the SOC.for Res. in Child Develpm., Minneapolis, Minn.. March, 1965. Bandura, A.. lk Walters, R. H.Social learning and personality development. New York: Holt, 1963. Barnett, C. D.. Pryer, Margaret W., & Ellis, N. R. Experimental manipulation of verbal behavior in defectives. Psychol. Rep., 1959, 5, 393-396. Barrett, Beatrice H., & Lindsley, 0. R. Deficits in acquisition of operant discrimination and differentiation shown by institutionalized retarded children. Amcr. J. ment. Defic., 1962, 67, 424-436. Baumeister, A. A., Beedle, R., & Urquhart, D. GSR conditioning in normals and retardates. Amer. J. ment. Defic., 1964, 69, 114-120. Behrens, R. F., & Ellis, N. R. Simultaneous and trace eyelid conditioning in normals and defectives. In R. L. Cromwell (Ed.) Abstracts of Peabody studies in mental retardation, 1960-1962. George Peabody Coll. for Teachers, 1962, Vol. 2 (Abstract No. 20). Bensberg, C. J., Colwell, C. N., & Caapel, R. H. Teaching the profoundly retarded

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self-help skill activities by behavior shaping techniques. Amer. J . ment. Defic., 1965,

69, 674-679.

Berkson, G., & Davenport, R. K. Stereotyped movements of mental defectives: I. Initial survey. Amer. J . ment. Defic., 1962, 66, 849-852. Bijou, S. W., & Orlando, R. Rapid development of multiple-schedule performances with retarded children. J. exp. anal. Behav., 1961, 4, 7-16. Birnbrauer, J. S., Bijou, S. W., Wolf, M. M., -& Kidder, J. D. Programmed instruction in the classroom. In L. Ullmann & L. Krasner (Eds.), Case studies in behauior modification. New York: Holt, 1965. Birnbrauer, J. S., & Lawler, Julia. Token reinforcement for learning. Ment. Retard., 1964, 2, 275-279. Blackwood, R. 0. Operant conditioning as a method of training the mentally retarded. Unpublished Ph.D. dissertation, Dep. of Psychol., Ohio State Univer., 1962. Bowers, C. Y., Gordon, D. L., & Segaloff, A. The myxedema reflex in infants and children with hypothyroidism. J. Pediat., 1959, 54, 46-49. Butterfield, E. C. A provocative case of over-achievement by a mongoloid. Amer. 1. ment. Defic., 1961, 66, 444-448. Carter, P. H. (Ed.) Medical aspects of mental retardation. Springfield, Ill.: Thomas, 1965. Cromwell, R. L., Palk, B. E., & Foshee, J . G. Studies in activity level: V. T h e relationships among eyelid conditioning intelligence activity level, and age. Amer. J. ment. Defic., 1961, 65, 744-748. Davenport, R. K., & Berkson, G. Stereotyped movements of mental defectives: 11. Effects of novel objects. Amer. I . ment. Defic., 1963, 67, 879-882. Dayan, M. Toilet training retarded children in a state residential institution. Ment. Retard., 1964, 2, 116-117. Eimas, P. D. Components and compounds in discrimination learning of retarded children. J. e x p . child Psychol., 1964, 1, 301-310. Ellis, N. R. Amount of reward and operant behavior in mental defectives. Amer. J. ment. Defic., 1962, 66, 595-599. Ellis, N. R. Toilet training the severely defective patient: an S-R reinforcement analysis. Amer. J . ment. Defic., 1963, 68, 98-103. Ellis, N. R. Experimental approaches to behavioral engineering: considerations in establishing more adequate behavioral patterns and response repertoires in the retarded. Paper delivered at the Ameri. Psychol. Ass. Meeting, Los Angeles, 1964. Ellis, N. R., Barnett, C. D., & Pryer, Margaret W. Operant behavior in mental defectives: exploratory studies. J . exp. anal. Behav., 1960, 3 , 63-69. Ellis, N. R., Girardeau, F. L., & Pryer, Margaret W. Analysis of learning sets in normal and severely defective humans. J . comp. physiol. Psycho[., 1962, 55, 860-865. Estes, W. K. An experimental study of punishment. Psychol. Monogr., 1944, NO. 57. Ferster, C. B.,& Skinner, B. F. Schedules of reinforcement. New York: Appleton, 1957. Franks, C. M. Individual differences in conditioning and associated techniques. In J. Wolpe, A. Salter & L. J. Reyna (Eds.), The conditioning therapies. New York: Holt, 1964. Franks, V. An experimental study of conditioning and learning in mental defectives. Unpublished Ph.D. dissertation, Univer. of London. 1959. Fuller, P. R. Operant conditioning of a vegetative human organism. Amer. J . Psychol., 1949, 62, 587-599. Girardeau, F. L., & Spradlin, J. E. Token rewards o n a cottage program. Ment. Retard., 1964, 2, 345-351. Cove, R. M., Lawson, R., & Watson L. S., Jr. Operant conditioning with severely and profoundly mentally retarded children. Unpublished manuscript, Columbus State Sch., 1964.

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Gnngs, W. W., Lockhart, R. A., & Dameron, L. E. Conditioning autonomic responses of mentally subnormal individuals. Psychol. Monogr., 1962, 76, 1-35. Harris, Florence R.,Wolf, M. M., & Baer, D. M. Effects of adult social reinforcement on child behavior. Young Child, 1964, 20, 8-17. Headrick, Mary W. Effects of instructions and initial reinforcement on fixed-interval behavior in retardates. Amer. J . ment. Defic., 1963, 68, 425-432. Heard, W. G. Extension of the method of the laboratory study of reading acquisition to retarded children. Unpublished Ph.D. dissertation. Arizona State Univer., 1 W . Herman, R. L., & Azrin, N. H.Punishment by noise in an alternate response situation. J . exp. anal. Behav., 1964, 7, 185-188. Hollis, J. H. Solution of bent-wire problems by severely retarded children. A n e r . J. ment. Defic., 1962, 67, 463-472. Hollis, J. H. T h e effects of social and nonsocial stimuli on the behavior of profoundly retarded children: Part 1. Amer. J. ment. Defic., 1965, 69, 755-771. (a) Hollis, J. H. T h e effects of social and nonsocial stimuli on the behavior of profoundly retarded children: Part 2. Amer. J . ment. Defic., 1965, 69, 772-789. (b) Hollis, J. H. Effects of reinforcement shifts on bent-wire performance of severely retarded children. Amer. J . ment. Defic., 1965, 69, 531-535. (c) Holz, W. C., & Azrin, N. H. Discriminative properties of punishment. J. exp. anal. Behav., 1961, 4, 225-232. Holz, W. C.,& Azrin, N. H. Interactions between the discriminative and aversive properties of punishment. J. exp. anal. Behav., 1962, 5, 229-234. Holz, W. C., & Azrin, N. H. A comparison of several procedures for eliminating behavior. 1. exp. anal. Behav., 1963, 6, 399-406. Hundziak, M., & Maurer, R. A. A comparison of nursing care for profoundly mentally retarded boys in large and small groups. Unpublished manuscript, Columbus State Sch., 1963. Hundziak, M., Maurer, R. A., & Watson, L. S., Jr. Operant conditioning in toilet training of severely mentally retarded boys: a controlled study. Unpublished manuscript. Columbus State Sch., 1963. Kaufman, M. E., & Levitt, H. A study of three stereotyped behaviors in institutionalized mental defectives. Amer. J . ment. Defic., 1965, 69, 467-473. Keller, F. S., & Schoenfeld, W. N. Principles of psychology. New York: Appleton, 1950. Kerr, N., Meyerson, L., & Michael, J. L. A procedure for shaping vocalizations in a mute child. In L. P. Ullmann & L. Krasner (Eds.), Case studies in behavior modificatiott. New York: Holt, 1965. Lane, H., & Curran, C. Gradients of auditory generalization for blind, retarded children. J . exp. anal. Behav., 1963, 6, 585-588. Lawson, J. D. T h e free Achilles reflex in hypothyroidism and hyperthyroidism. New Engl. J . Med., 1958, 259, 761-765. Levitt, H., & Kaufman, M. E. Sound induced drive and stereotyped behavior in mental defectives. Amer. J. ment. Defic., 1965, 69, 729-734. Lindsley, 0. R. Direct measurement and prosthesis of retarded behavior. J. Educ., 1964, 147, 62-81. Lipman, R. S. Learning: verbal, perceptual-motor, and classical conditioning. In N. R. Ellis (Ed.), Handbook of mental deficiency: psychological theory and research. New York: McGraw-Hill, 1963. Locke, B. J. T h e effects of examiner, role, and reinforcement variables on the modification of verbal behavior in institutionalized retardates. Unpublished Ph.D. dissertation, Oklahoma State Univer., Stillwater, 1962.

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