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Consistency of emission order in free recall
JOURNAL OF VERBAL LEARNING AND VERBALBEHAVIOR 9,
58-68 (1970)
Consistency of Emission O r d e r in Free Recall I WILLIAM P . WA LLA C E
University of Nevada, Reno, Nevada 89507 Phenomena of clustering and subjective organization in free recall were incorporated within an associative explanatory framework. Both are defined by consistency of recall orders. Recall-order consistency was assumed to reflect the organization S imposes upon material he is required to memorize. Contiguity of experience ("thinking" about items together during the experiment) was proposed as the dominant force underlying the consistency in recall order. According to the contiguity principle, items experienced together will be recalled together. The major determinants of specific contiguity relations identified were the arrangement of items during study trials by E, the arrangement of items during test trials by S, and modifications of prior input and output orders which result from rehearsal and mediating activities on the part of S. In a free-recall task Ss are presented with a list of verbal materials to study (occasionally pictures or objects are used), and after a brief interval they are asked to recall as many of these items as possible. There may be several such study and recall trials, or there may be just one study trial and one recall trial. The exceptional feature of the free-recall procedure is the license S has in ordering the items he recalls. There is a growing body of evidence which suggests that during a free-recall task Ss group items into higher-order units (Mandler, 1967; Tulving, 1968). The grouping or organizing activity enables Ss to overcome limitations on the amount of information they are capable of processing (Miller, 1956). Thus, recalling a single unit from a free-recall list may result in the "retrieval" of several specific list items. It has been assumed that this organizational process in memory is reflected by S's ordering of items during recall. The purpose of the present article is to suggest a general principle by which specific items in a free-recall list are organized into common higher-order units. It will be argued here that during the learning task contiguous experience of specific list members is respon-
sible for the development of associations; associations which determine specific unit content and consistency in ordering recall. The present emphasis is on how specific items are brought into contiguous positions. However, before describing the operation of the contiguity principle, further clarification of the term "organization in free recall" is in order. Organization in recall is inferred from two critical attributes of free-recall order: stability and identifiability. In suggesting a general use for the term organization, Mandler (1967) has stated: " A set of objects or events are said to be organized when a consistent relation among the members of the set can be specified and, specifically, when membership of the objects in subsets (groups, concepts, categories, chunks) is stable and identifiable" (p. 330). Recent research with multitrial free recall of "unrelated" words suggests that stability of recall order is sufficient to infer that organization has taken place (e.g., Tulving, 1962b, 1964). Thus, it is inferred that list items have been organized when Ss group item sduring recall according to some identifiable relations or when the same grouping of items occurs consistently across successive trials. In the present report the term organization will be used to refer to recall orders character-
i This project was s u p p o r t e d by G r a n t GB8605 from
the National Science Foundation. 58
CONSISTENCY OF RECALL ORDER
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as applied to order of free recall states that there is a tendency to recall together items which have been experienced together. During a free-recall task, items which occur in adjacent positions during input (study trials) or previous output (recall trials) will be more likely to occur in adjacent positions during subsequent output. The probability that items will occur contiguously in recall is a function of their associative strength, which is influenced by repetitions of prior contiguous experiences ("thinking" about items together). Thus, organization in recall is viewed here as an associative process. Contiguity of experience during sequential presentation of list items (both input and output trials) leads to the development of associations responsible for the content of "organized" units. Preexperimental associations and nonassociative relations operate to determine specific contiguity experiences during the course of practice. It should be noted that the contiguity principle can allow for within- and betweencategory variability in recall order. Such variation may reflect variability in contiguity relations, and it may reflect the fact that sequential recall order provides a less than perfect index of organization in memory. The fact that Ss can modify their recall order to correspond with experimental or self instructions (e.g., Bousfield & Abramczyk, 1966; Hudson, 1968; Tulving, 1962a) or output cues (e.g., Tulving & Pearlstone, 1966) poses no special problem. On the first recall trial that such instructions or cues are provided Ss may edit their responses during recall, recording items in an order compatible with the instructions or cues. On subsequent trials the contiguity relations established by rehearsal may be expected to correspond with CONTIGUITY PRINCIPLE the suggested relations, or additional inIt has been demonstrated that associative structional sets may be adopted which would strength between two items can develop on the interfere with the development of consistent basis of the contiguous occurrence of those emission order in recall. Association by items (Keppel, 1966; Spear, Ekstrand, & contiguity is used here as a dispositional Underwood, 1964). The principle of contiguity concept (Postman, 1968). There are several
ized by stability or adherence to identifiable grouping relations. Two recall-order phenomena have been described in the literature: clustering (e.g., Bousfield, 1953) and subjective organization (e.g., Tulving, 1962b). Both are characterized by a consistency of recall order. In clustering, organization is inferred from a consistency between the grouping of items in recall and some predetermined grouping of items. In subjective organization, the consistency from which organization is inferred is between recall orders on successive recall trials. Although clustering and subjective organization are operationally distinct, it is assumed here that they reflect the operation of common processes. Clustering and subjective organization refer to recall-order phenomena which share an essential characteristic: Nonrandomness of emission order in free recall. With respect to subjective organization, nonrandomness of recall order may provide the core of an argument against an associative interpretation, since the recall list involves "unrelated" materials, and presentation procedures insure that specific sequential adjacencies do not recur during input. Similarly, demonstrations of clustering in the absence of interitem associations may be viewed as damaging to an associational position (e.g., t~oberts, 1968). One task set for the associative theorist is to account for nonrandom recall sequences in the free recall of items that are not associatively related (as determined from normative data). It is argued here that Ss actively associate items during the study and test phases of a free-recall task, and consequently items that are not associatively related prior to learning may be associated during the learning task.
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factors which may determine specific contiguous relations among items, and it should be emphasized that these factors operate during recall trials, as well as during study trials. Thus, recall order is viewed as being associatively determined, and superordinate systems (e.g., Bousfield, 1953), coding activities (e.g., Cohen, 1966), organizational rules (e.g., Pollio, Kasschau, & DeNise, 1968), etc., function such that "unitized" items are processed contiguously. No attempt is made to explain the development of pre-experimental habits responsible for specific items appearing contiguously. The application of an association principle to free-recall phenomena is not new (Corer, 1965, 1967; Deese, 1959a, 1959b, 1960). Wood (1969) referred to the development of sequential associations in describing the nature of organization in free-recall learning. Generally, interpretations of clustering in free recall have emphasized either interitem associations or higher-order memory codes (e.g., category names). Although a considerable amount of effort has been devoted to contrasting these two interpretations (e.g., Allen, Puff, & Weist, 1968; Bousfield, Steward, & Cowan, 1964; Cofer, 1966, Cofer, Bruce, & Reicher, 1966; Marshall, 1967a, 1967b), it has been argued that attempts to distinguish between associative and coding mechanisms of clustering are of little utility (Cofer, 1965; Tulving, 1968). The present extension of the contiguity principle also regards such a distinction as unnecessary. The content of memory units is viewed here as being determined by specific contiguity relations of list items, and both direct associations and "coding" activities may operate to influence the specific contiguity relations experienced. FACTORS DETERMINING CONTIGUITY RELATIONS
Nominal Input Order There are two components of the free-recall procedure during which Ss are exposed to list
items: the study trial and the recall trial. The order that items are presented to Ss provides one source of specific contiguity experiences, and the order that items are recalled provides a second source of specific contiguity experiences. If contiguity of experience influences organization at recall, then one may expect substantial agreement between corresponding input orders and output orders, and between successive output orders. Agreement between successive output orders has been well substantiated and describes the empirical phenomenon of subjective organization (e.g., Tulving, 1962b). However, with standard free-recall procedures there is generally very little agreement between input order and output order (Asch & Ebenholtz, 1962). Asch and Ebenholtz varied input order across trials and considered only the immediately preceding input order when assessing the agreement between input order and output order. Repetitions of specific input orders across trials may be expected to strengthen sequential associations, consequently the probability that output orders will agree with input orders ought to be higher when the same input order is used on all trials, compared to the standard procedure of varying input orders across trials. Although Waugh (1961) and Stimmel and Stimmel (1967) failed to demonstrate that constant input order across trials enhanced recall, Lachman and Laughery (1968) and Jung and Skeebo (1967) reported such facilitation. Jung and Skeebo also found that output order following a constant input order changed over trials, becoming more like recall orders typical in serial learning. Mandler and Dean (1969) presented Ss with 16 word free-recall lists. They included a variety of presentation procedures, but of immediate concern here was their variation of input order. The words were presented in a constant order or in a different random order on each trial. Recall scores and subjective organization scores were enhanced following constant input order. Further, there was substantial agreement between the input order and the
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output order for the constant order conditions. In addition to constant input order, the agreement between input order and output order is high when the length of the free-recall list falls within the immediate memory span (e.g., Bousfield & Abramczyk, 1966; Jahnke, 1965) and when the list order approximates language structure (e.g., Deese & Kaufman, 1957; Postman & Adams, 1960). It has been argued that because the freerecall p a r a d i g m " . . , involves presentation of material completely free from any sequential redundancy, such redundancy or organization in subject's recall cannot be attributed to the input material" (Tulving, 1962b, p. 345). There is little agreement between input and output orders of unrelated words with standard freerecall procedures, but this poses a serious difficultyfor the contiguity position only if two assumptions are tenable: (a) the order that items in a free-recall list are presented to Ss faithfully reflects the sequential order in which they are processed, and (b) varyinginput orders across trials in a random fashion guarantees that sequential redundancy during input cannot be attained. In the following sections an alternative possibility will be explored, viz., that there is a discrepancy between the order in which items are presented to S (nominal input order) and the order in which presented items are processed in memory (functional input order). The implication of this possibility is that only agreement between output order and functional input order is critical to the contiguity position, and merely comparing nominal input order and output order has little relevance to an evaluation of the contiguity principle.
Functional Input Order It is not unreasonable to assume that even in a simple learning experiment human Ss may act upon their environment and alter it in some way. For example, in paired-associate learning Underwood (1963) distinguished between the nominal stimulus and the functional stimulus. That is, Ss may alter the
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stimulus term (e.g., use only the initial letter) and form an association between this modified stimulus and the response. Cooper and Pantie (1967) have made a similar distinction with respect to an S's use of study time. It is suggested here that Ss may act upon list items as they are presented during a free-recall task, thereby processing items in a sequential order not identical to the nominal presentation order. Any departure on the part of Ss from the rote, mechanical repetition of exactly what is presented to them may disrupt the nominal order of processing information. For example, it is reasonable to assume that Ss rehearse items during study trials, and further, that Ss do not necessarily rehearse items in the order that they are presented (Mechanic & Mechanic, 1967). That is, if the items check, force, body, and desert are presented in that order, an individual S may rehearse check when body appears. Thus, the nominal input order is check, force, body, desert, but the functional input order is check, force, body, check, desert. The contiguity relations assumed from the nominal input order differ from the functional contiguity relations. Ekstrand (1966) has pointed out that comparisons of stimulus recall and response recall in pairedassociate learning do not provide fair tests of associative symmetry if there is a discrepancy between the nominal stimulus and the functional stimulus. It is also true that agreement between input orders and output orders in free recall does not provide a fair test of the contiguity principle if there is a discrepancy between the nominal input order and the functional input order. Varying nominal input order across trials does not guarantee that the list is free from functional sequential redundancy. Rehearsal. Rehearsal of list items during study trials and during test trials is one major activity which may alter the nominal contiguity relations among list members. Procedures which minimize the opportunity for rehearsal. ought to slow the development of organization and lead to organization in recall which more
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closely follows nominal input order. Rehearsal prevention activities during study trials have been shown to depress recall (Allen, 1968; Glanzer & Meinzer, 1967) and subjective organization (Allen, 1968). Constant input order across trials, compared to varied input orders, may be expected to increase the stability of rehearsal order. The development of organization in free recall is enhanced following constant input orders (Mandler & Dean, 1969). Recall-trial activity may be an important factor in multitrial free recall. The recall trial cannot be considered as only providing measurement without contaminating future measurement (Lachman & Laughery, 1968; Tulving, 1967). When Ss are allowed to study an ordered array of words, they show a strong tendency to reproduce the words in the same order as they appeared on the study sheet (Wallace, 1969). It is reasonable to assume that Ss rehearse items in an order that corresponds with spatial location on recall sheets (e.g., in a top-to-bottom order or in a left-to-right order). The rehearsal activity serves to strengthen and develop associations between items recalled in close temporal proximity. Subjective organization is defined by consistency in ordering items across successive recall trials, thus allowing S free study of a preceding recall order ought to enhance organization scores. When conditions are arranged so that rehearsal order (spatial location on recall sheets) does not correspond to the temporal recall order, the development of organization is disrupted (Wallace, 1969). Studies of organization in free recall have given little attention to learning activities that transpire during recall trials. If rehearsal during recall trials is important to the emergegence of organized recall, then the development of organization ought to be relatively slow when the training procedure consists of repeated study trials without interspersed test trials, and it ought to be facilitated following a training procedure involving repeated test trials separated by occasional study trials. It
may be noted that this latter expectation that organization should increase across test trials not separated by a study trial represents a prediction of a discrepancy between recall and organization, since recall has been demonstrated to decline slightly across test trials not separated by a study trial (e.g., Tulving, 1967). It seems reasonable that the more time S is allowed for recall, the greater is his opportunity to review his recall, and allowing S to write his responses during recall makes it easier for him to review previous contiguous relations. The majority of studies concerned with multitrial free recall have utilized writtenrecall procedures and generally allowed Ss ample time for recall (e.g., Bousfield & Cohen, 1953; Paivio, Rogers, & Smythe, 1968; Puff & Bousfield, 1967; Puff & Hyson, 1967; Tulving, McNulty, & Ozier, 1965). There is evidence that organization develops with oral-recall methods (Mayhew, 1967; Segal & Mandler, 1967; Tulving, 1964; Tulving & Osler, 1967), but organization in recall is depressed when recall is oral and when recall duration is relatively brief (Wallace, 1969). There have been efforts to prevent Ss from studying their recall sheets by not allowing them to view previous responses (Abramczyk & Bousfield, 1967; Bousfield & Abramczyk, 1966). However, contrary to expectations based on the present contiguity orientation, Allen (1968) found that covering responses during recall had little effect on recall or organization scores, Mediating responses. The presentation of a verbal unit may elicit a variety of implicit responses (Bousfield, Whitmarsh, & Danick, 1958; Mandler, 1954), and these implicit responses may function to bring temporally disparate items into contiguous positions. Underwood (1965) presented Ss with a long series of words and asked them to indicate whether each word had appeared earlier in the series. Critical test words presented for the first time, but related to earlier list words, elicited more "false positives" (Ss reported
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having seen them earlier) than appropriate control words. Underwood argued that when the related words were presented early in the list, the corresponding critical test words were elicited implicitly as associational responses. Thus, each critical test word acquired some presentation frequency, which increased the difficulty of correctly identifying it as a first occurrence. The occurrence of such mediating responses provides a second way in which contiguity relations within a free-recall list may be altered from the nominal input order. For example, assume that during a study trial the word man appears early in the list. Upon the presentation of this item, S responds implicitly with woman. Assume further that the word woman actually appears later in the list, at which time S responds implicitly with man. The implicit response mechanism has placed in contiguous positions items which were separated during the study trial by several other items. In this fashion, implicit responses may directly modify nominal input contiguity relations. The mediating mechanism may also operate indirectly by initiating contiguous rehearsal of list members. That is, the mediating response need not occur directly in the list, but if it links list members, and they in turn are rehearsed together, it has served to establish the contiguous occurrence of specific list members that may be temporally spaced. If the word canary appears at one position in a free-recall list and S responds implicitly with yellow and the word banana appears at some position removed from canary and S again responds implicitly with yellow, this second implicit response may lead to the implicit response (rehearsal) of canary by means of a backward association (cf., Wood & Underwood, 1967). Thus, two words may be functionally contiguous if they elicit a common implicit response. The preceding examples of direct and indirect mediating responses have utilized agsociative implicit responses. However, there
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is no intention of restricting the present analysis to conventional associative responses. Two smudges on the memory-drum tape may serve to bring items into contiguous positions, provided that S responds appropriately to the smudge stimulus. Any conceptual basis for grouping items may be used by S, provided that the critical relationships among stimuli are recognized. It follows from the preceding arguments that concept identification is an important component of organization in free recall. Ignoring the problem of the original formation of concepts, it can be stated that variables which facilitate concept identification, and that can be translated to the free-recall situation, ought to increase the development of organization. Underwood (1952) has stated: "For the perception of relationships among stimuli the needed assumption is that the appropriate responses to these stimuli be contiguous" (p. 211). Variations in procedures expected to bring common implicit responses into closer continguity ought to enhance organization in free recall. Blocked or constrained presentation order during which all members from one category are presented, and then all members of a second category are presented, etc., has been shown to facilitate both clustering and recall, compared to random presentation orders (e.g., Cofer et al., 1966; Tulving, 1965; Weingartner, 1964). The facilitating effect on recall of presenting low-strength associates in a list decreases as the number of items intervening between the presentations increases (Glanzer, 1969). Puff (1966) demonstrated that both recall and organization increased following an increase in the number of times words immediately preceded other words from the same category. Presumably, blocked presentation order increases the likelihood that the common implicit response to related items will occur several times in close temporal proximity, although Ss receiving blocked input order also have the advantage that nominal input contiguity corresponds to the predetermined basis for organization.
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However, Puff (1966) has indicated that of the contiguity principle make such a agreement with nominal input order cannot uniprocess model general enough to incoraccount for all of the advantage of blocked porate the wide assortment of clustering input. relations. Procedures designed to facilitate or interfere In summary, mediating responses serve to with the implicit-response mechanism ought alter the functional contiguity relations among to alter organization in free recall. For example, a list of words. They do this directly if the the stronger the natural relations between list implicit response is also a list member or items and the common associative response indirectly by priming contiguous rehearsal of which links them together, the greater the list members linked by a common implicit likelihood that these items will be brought response. The implicit response does not have into contiguous relations. The amount of to be an associative response, it need only be a clustering in free recall has been shown to be common "tag" for two or more items. If S can directly related to the strength (based upon get from this tag the second time it occurs as an normative data) of common associative re- implicit response to the first item for which he sponses (e.g., Bousfield, Cohen, & Whit- used the tag, then the two items have been marsh, 1958; Bousfield & Puff, 1964; Bous- brought into contiguous positions. When field, Steward, & Cowan, 1964; Jenkins, overlapping conceptual relations among list Mink, & Russell, 1958; Matthews, Marcer, & members exist, it is expected that the most Morgan, 1964). Increasing the number of salient response tendencies will determine the trials in free recall may be expected to increase specific organizational structure observed the strength of common associative responses, (Lambert, Ignatow, & Krauthamer, 1968). it and both clustering (e.g., Bousfield & Cohen, should be noted that while the mediating1953; Robinson, 1966) and subjective organi- response mechanism extends the applicability zation (e.g., Tulving, 1962b) have been shown of an association-by-contiguity principle, it to increase across trials. It has been suggested also may weaken the principle by making it too that implicit responding does not occur general. That is, if clustering fails to occur on readily under conditions of incidental learning, some predetermined basis, such as form class and with this procedure the amount of cluster- (Cofer & Bruce, 1965; Koplin & Moates, ing in free recall appears to be reduced 1968) or common decoding rules (Underwood (Wallace & Calderone, 1969). It has also been & Erlebacher, 1965), one may simply argue suggested that mediation is related to intellec- that the appropriate implicit responses did not tual development of Ss (e.g., Kendler, occur. We know the appropriate implicit Kendler, & Wells, 1960; Reese, 1962), and responses occurred when we observe clusteramount of clustering has been shown to be ing! However, the circle can be broken by directly related to developmental level of Ss examining clustering in cases where the critical (Bousfield, Esterson, & Whitmarsh, 1958; relationships can be dimensionalized, or in cases where variables that influence the obGerjuoy & Spitz, 1966). Bousfield and Bousfield (1966) identified 15 viousness of the basis for grouping items can be unifying characteristics found among items identified (e.g., clustering must be more grouped together in recall. These character- pronounced with high-strength associates than istics varied from simple associative relations with low-strength associates). Merely explorto more complex linguistic factors. Does the ing whether a particular relationship among existence of different characteristics relating items will provide a sufficient basis for clusterclustered items force acceptance of a multiple- ing will have little relevance to an evaluation process theory ? It is argued here that it does of the present extension of the contiguity not. The rehearsal and mediating extensions principle.
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ANOVERVIEW The arguments raised in the present discussion attempted to describe activities of Ss engaged in a free-recall task. The present proposal reflects the view that a description of the activities of Ss engaged in free recall will facilitate our understanding of the product of those activities, viz., organized recall. The rehearsal and mediating activities of Ss described here are influenced by characteristics of the stimulus materials and experimental procedures. It was reasoned that the rehearsal and mediating activities result in repetitions of specific contiguity experiences (specific list members are practiced together regularly). It is known that contiguity provides a sufficient basis for the development of associations. Also, it is known that associatively related items cluster in recall protocols, presumably because the recall of one associate cues or enhances the probability of the immediate recall of other list associates. Demonstrations of"nonassociative" organization in free recall are viewed here as reflecting the operation of an associative process. Recently, Slamecka (1968) presented evidence that recall is not enhanced when subsets of the list are presented as cues for Ss. Freund and Underwood (1969) demonstrated similar results with a variation in testing procedures. Such evidence may be construed as damaging to the present contiguity interpretation. However, Allen (1969) has argued that some organization must develop before one may expect facilitation from a subset of list items that serve as cues, and one needs to identify the specific organizational structure to maximize facilitation from such cues, i.e., if S organizes a list of 10 words into five pairs, maximal facilitation from cuing would result by presenting one member of each pair as a cue word. Allen demonstrated that cuing facilitated recall under conditions designed to optimize the cuing effect. The present extension of the contiguity principle has been suggested as an alternative way of viewing "organizing" behavior in free 3
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recall. Current theoretical viewpoints have been summarized in a recent review by Shuell (1969). These theoretical statements have focused on one or more of the grouping principles (e.g., category codes, direct associations, etc.) in accounting for organizational phenomena. As Shuell suggests, it does not appear that all of the relevant data can be incorporated within a single grouping principle. The present extension of the contiguity principle emphasizes that all grouping relations may accomplish the same end, viz., the contiguous experience of specific items. The advantage of such thinking is that a single mechanism can then account for grouping items in recall. Most of the existing data on organization in recall fit this contiguity model, and the model generates additional predictions. In general, procedures that enhance contiguity experiences must facilitate organization, and procedures that disrupt contiguity experiences must interfere with organization. Positive results from such research can be incorporated easily within other theoretical frameworks, provided that they acknowledge that instance contiguity is sufficient for organizational units to develop. Negative data from such research is only damaging to the contiguity view. The research reviewed in the present report is consistent with expectations from the contiguity position (with the exception of Allen's (1968) data on output viewing conditions). It would be difficult to contrast empirically the present notion with existing views. The reason for this difficulty is that most theorists may be willing to accept contiguity (as proposed here) as one mechanism of organization. The present discussion represents an attempt to describe how contiguity may be basic to a wide range of demonstrations of organized recall. It seems reasonable that the mediating and rehearsal activities described here take place during input and output phases of a free-recall task. It remains to be verified that the consistent contiguity experiences presumed to result from such activities produce organized recall.
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As mentioned earlier with respect to clustering, the real danger concerning a unitizing principle like the one proposed is that it is so general that it incorporates everything without the possibility of being refuted. The rehearsal and mediation extensions proposed in this report enable the associative theorist to account for data that could not be handled within the limitations set by restricting associations to pre-experimental language habits or those that may develop during the experiment from nominal input-order contiguity. While these extensions may weaken the principle, it has been argued here that the contiguity principle is falsifiable. REFERENCES ABRAMCZYK,R. R., & BOUSFIELD,W. A. Sequential ordering in repeated free recall as a function of interitem associative strength. Psychological Record, 1967, 17, 183-192. ALLEN, M. Rehearsal strategies and response cueing as determinants of organization in free recall.
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EKSTRAND,B. R. Backward associations. Psychological Bulletin, 1966, 65, 50-64.
CONSISTENCY OF RECALL ORDER FREUND, J. S., & UNDERWOOD, B. J. Storage and retrieval cues in free recall learning. Journal of Experimental Psychology, 1969, 81, 49-53. GERJUOY, I. R., & SPITZ, H. H. Associative clustering in free recall: Intellectual and developmental variables. American Journal of Mental Deficiency, 1966, 70, 918-927. GLANZER, M. Distance between related words in free recall: Trace of the STS. Journal of Verbal Learning and Verbal Behavior, 1969, 8, 105-111. GLANZER, M., & MEINZER, A. The effects of intralist activity on free recall. Journal of Verbal Learning and Verbal Behavior, 1967, 6, 928-935. HUDSON,R. L. Category clustering as a function of level of information and number of stimulus presentations. Journal of Verbal Learning and Verbal Behavior, 1968, 7, 1106-1108. JAHNKE, J. C. Primacy and recency effects in serialposition curves of immediate recall. Journal of ExperimentalPsychology, 1965, 70, 130-132. JENKINS, J. J., MINK, W. D., & RUSSELL, W. A. Associative clustering as a function of verbal association strength. Psychological Reports, 1958, 4, 127-136. JUNG, J., & SKEEBO,S. Multi-trial recall as a function of constant versus varied input orders and list length. Canadian Journal of Psychology, 1967, 21, 329-336. KENDLER, T. S., KENDLER, H. H., & WELLS, D. Reversal and nonreversal shifts in nursery school children. Journal of Comparative and Physiological Psychology, 1960, 53, 83-88. KEPPEL, G. Association by contiguity: Role of response availability. Journal of Experimental Psychology, 1966, 71, 624-628. KOPLIN, J. H., & MOATES,D. R. Form-class clustering in recall with relevant or irrelevant prior exposure.
Journal of Verbal Learning and Verbal Behavior, 1968, 7, 263-264. LACHMAN, R., & LAUGHERY, K. R. Is a test trial a training trial in free recall learning? Journal of Experimental Psychology, 1968, 76, 40-50. LAMBERT, W. E., IGNATOW, M., & KRAUTHAMER,M. Bilingual organization in free recall. Journal of Verbal Learning and Verbal Behavior, 1968, 7, 207-214. MANDLER, G. Response factors in human learning. Psychological Review, 1954, 61, 235-244. MANDLER, G. Organization and memory. In K. W. Spence and J. T. Spence (Eds.), The psychology of learning and motivation. New York: Academic Press, 1967. MANDLER, G., & DEAN, P. J. Seriation: The development of serial order in free recall. Journal of ExperimentalPsychology, 1969, 81, 207-215.
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MARSHALL,G. R. Effect of total association and conceptual cohesiveness among words on recall, clustering, and recognition association. Psychological Reports, 1967, 20, 39-44. (a) MARSHALL,G. R. Stimulus characteristics contributing to organization in free recall. Journal of Verbal Learning and Verbal Behavior, 1967, 6, 364-374.
(b) MATTHEWS, W. A., MARCER, D., & MORGAN, E. Word association hierarchies and free recall.
Journal of Verbal Learning and Verbal Behavior, 1964, 3, 371-375.
MAYHEW,A. J. Interlist changes in subjective organization during free-recall learning. Journal of Experimental Psychology, 1967, 74, 425-430. MECHANIC,A., & MECHANIC,J. D. Response activities and the mechanism of selectivity in incidental learning. Journal of Verbal Learning and Verbal Behavior, 1967, 6, 389-397. MILLER, G. A. The magical number seven, plus or minus two: Some limits on our capacity for processing information. Psychological Review, 1956, 63, 81-97. PAIVIO, A., ROGERS, Z. B., & SMYTHE,P. C. Why are pictures easier to recall than words ? Psychonomic Science, 1968, 11, 137-138. POLLIO, H. R., KASSCHAU,R. A., & DENISE, H. E. Associative structure and the temporal characteristics of free recall. Journal of Experimental Psychology, 1968, 76, 190-197. POSTMAN, L. Association and performance in the analysis of verbal learning. In T. R. Dixon and D. L. Horton (Eds.), Verbal behavior and general behavior theory, Englewood Cliffs, New Jersey: Prentice-Hall, 1968.
POSTMAN, L., & ADAMS, P. A. Studies in incidental learning:VIII. The effects of contextual determination. Journal of Experimental Psychology, 1960, 59, 153-164. PUFF, C. R. Clustering as a function of the sequential organization of stimulus word lists. Journal of Verbal Learning and Verbal Behavior, 1966, 5, 503-506.
PUFF, C. R., • BOUSFIELD,W. A. Development of intertrial organization with simultaneous presentation of stimulus items. Journalof VerbalLearning and Verbal Behavior, 1967, 6, 213-215. PUFF, C. R., & HYSON,S. P. An empirical comparison of two measures of intertrial organization in free recall. Psychonomic Science, 1967, 9, 329-330. REESE, H. W. Verbal mediation as a function of age level Psychological Bulletin, 1962, 59, 502-509. ROBERTS, W. A. Alphabetic coding and individual differences in modes of organization in free recall learning. American Journal of Psychology, 1968, 81, 433-438.
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ROBINSON, J. A. Category clustering in free recall Journal of Psychology, 1966, 62, 279-285 SEGAL, M. A., & MANDLER, G. Directionality and organizational processes in paired-associate learning. Journal of Experimental Psychology, 1967, 74, 305-312. SHUELL,T. J. Clustering and organization in free recall Psychological Bulletin, 1969, in press. SLAMECKA, N. J. An examination of trace storage in free recall. Journal of Experimental Psychology, 1968, 76, 504-513. SPEAR, N. E., EKSTRAND,B. R., & UNDERWOOD,B. J. Association by contiguity. Journal of Experimental Psychology, 1964, 67, 151-161. STIMMEL, D. T., & STIMMEL, N. S. Free recall as a function of intralist similarity and order of presentation constraints. Psychological Reports, 1967, 21,541-544. TULVlNG, E. The effect of alphabetical subjective organization on memorizing unrelated words. Canadian Journal of Psychology, 1962, 16, 185191. (a) TULVING, E. Subjective organization in free recall of "unrelated" words. Psychological Review, 1962, 69, 344-354. (b) TULVING, E. Intratrial and intertrial retention: Notes towards a theory of free recall verbal learning. Psychological Review, 1964, 71, 219-237. TULVING, E. The effect of order of presentation on learning of "unrelated" words. Psychonomic Science, 1965, 3, 337-338. TULVING, E. The effects of presentation and recall of material in free-recall learning. Journal of Verbal Learning and Verbal Behavior, 1967, 6, 175-184. TULVING, E. Theoretical issues in free recall. In T. R. Dixon and D. L. Horton (Eds.), Verbal behavior and general behavior theory. Englewood Cliffs, New Jersey: Prentice-Hall, 1968. TULVING, E., McNULTY, J. A., & OZIER, M. Vividness of words and learning to learn in free-recall learning. Canadian Journal of Psychology, 1965, 19, 242,-252.
TULVING,E., & OSLER,S. Transfer effects in whole/part free-recall learning. Canadian Journal of Psycholology, 1967, 21, 253-262. TULVlNG, E., & PEARLSTONE, Z. Availability versus accessibility of information in memory for words.
Journal of Verbal Learning and Verbal Behavior, 1966, 5, 381-391.
UNDERWOOD, B. J. An orientation for research on thinking. Psychological Review, 1952, 59, 209220. UNDERWOOD, B. J. Stimulus selection in verbal learning. In C. N. Cofer and B. S. Musgrave (Eds.),
Verbal behavior and learning: problems and proecesses. New York:McGraw-Hill, 1963. UNDERWOOD, B. J. False recognition produced by implicit verbal responses. Journal of Experimental Psychology, 1965, 70, 122-129. UNDERWOOD, B. J., & ERLEBACHER,A. H. Studies of coding in verbal learning. Psychological Monographs, 1965, 79, (Whole No. 606). WALLACE,W. P. Influence of test trials on the development of subjective organization in free recall. Journal of Experimental Psychology, 1969, 81, 527-535. WALLACE, W. P., & CALDERONE, R. N. Implicit responses in incidental learning. Journal of Verbal Learning and Verbal Behavior, 1969, 8, 136-142. WAUGH, N. C. Free versus serial recall. Journal of Experimental Psychology, 1961, 62, 496-502. WEINGARTNER,H. The free recall of sets of associatively related words. Journal of Verbal Learning and Verbal Behavior, 1964, 3, 6-10. WOOD, G. Higher order memory units and free recall learning. Journal of Experimental Psychology, 1969, 80, 286-288. WOOD, G., & UNDERWOOD,]3. J. Implicit responses and conceptual similarity. Journal of Verbal Learning and VerbalBehavior, 1967, 6, 1-10.
(Received August 30, 1969)
58-68 (1970)
Consistency of Emission O r d e r in Free Recall I WILLIAM P . WA LLA C E
University of Nevada, Reno, Nevada 89507 Phenomena of clustering and subjective organization in free recall were incorporated within an associative explanatory framework. Both are defined by consistency of recall orders. Recall-order consistency was assumed to reflect the organization S imposes upon material he is required to memorize. Contiguity of experience ("thinking" about items together during the experiment) was proposed as the dominant force underlying the consistency in recall order. According to the contiguity principle, items experienced together will be recalled together. The major determinants of specific contiguity relations identified were the arrangement of items during study trials by E, the arrangement of items during test trials by S, and modifications of prior input and output orders which result from rehearsal and mediating activities on the part of S. In a free-recall task Ss are presented with a list of verbal materials to study (occasionally pictures or objects are used), and after a brief interval they are asked to recall as many of these items as possible. There may be several such study and recall trials, or there may be just one study trial and one recall trial. The exceptional feature of the free-recall procedure is the license S has in ordering the items he recalls. There is a growing body of evidence which suggests that during a free-recall task Ss group items into higher-order units (Mandler, 1967; Tulving, 1968). The grouping or organizing activity enables Ss to overcome limitations on the amount of information they are capable of processing (Miller, 1956). Thus, recalling a single unit from a free-recall list may result in the "retrieval" of several specific list items. It has been assumed that this organizational process in memory is reflected by S's ordering of items during recall. The purpose of the present article is to suggest a general principle by which specific items in a free-recall list are organized into common higher-order units. It will be argued here that during the learning task contiguous experience of specific list members is respon-
sible for the development of associations; associations which determine specific unit content and consistency in ordering recall. The present emphasis is on how specific items are brought into contiguous positions. However, before describing the operation of the contiguity principle, further clarification of the term "organization in free recall" is in order. Organization in recall is inferred from two critical attributes of free-recall order: stability and identifiability. In suggesting a general use for the term organization, Mandler (1967) has stated: " A set of objects or events are said to be organized when a consistent relation among the members of the set can be specified and, specifically, when membership of the objects in subsets (groups, concepts, categories, chunks) is stable and identifiable" (p. 330). Recent research with multitrial free recall of "unrelated" words suggests that stability of recall order is sufficient to infer that organization has taken place (e.g., Tulving, 1962b, 1964). Thus, it is inferred that list items have been organized when Ss group item sduring recall according to some identifiable relations or when the same grouping of items occurs consistently across successive trials. In the present report the term organization will be used to refer to recall orders character-
i This project was s u p p o r t e d by G r a n t GB8605 from
the National Science Foundation. 58
CONSISTENCY OF RECALL ORDER
59
as applied to order of free recall states that there is a tendency to recall together items which have been experienced together. During a free-recall task, items which occur in adjacent positions during input (study trials) or previous output (recall trials) will be more likely to occur in adjacent positions during subsequent output. The probability that items will occur contiguously in recall is a function of their associative strength, which is influenced by repetitions of prior contiguous experiences ("thinking" about items together). Thus, organization in recall is viewed here as an associative process. Contiguity of experience during sequential presentation of list items (both input and output trials) leads to the development of associations responsible for the content of "organized" units. Preexperimental associations and nonassociative relations operate to determine specific contiguity experiences during the course of practice. It should be noted that the contiguity principle can allow for within- and betweencategory variability in recall order. Such variation may reflect variability in contiguity relations, and it may reflect the fact that sequential recall order provides a less than perfect index of organization in memory. The fact that Ss can modify their recall order to correspond with experimental or self instructions (e.g., Bousfield & Abramczyk, 1966; Hudson, 1968; Tulving, 1962a) or output cues (e.g., Tulving & Pearlstone, 1966) poses no special problem. On the first recall trial that such instructions or cues are provided Ss may edit their responses during recall, recording items in an order compatible with the instructions or cues. On subsequent trials the contiguity relations established by rehearsal may be expected to correspond with CONTIGUITY PRINCIPLE the suggested relations, or additional inIt has been demonstrated that associative structional sets may be adopted which would strength between two items can develop on the interfere with the development of consistent basis of the contiguous occurrence of those emission order in recall. Association by items (Keppel, 1966; Spear, Ekstrand, & contiguity is used here as a dispositional Underwood, 1964). The principle of contiguity concept (Postman, 1968). There are several
ized by stability or adherence to identifiable grouping relations. Two recall-order phenomena have been described in the literature: clustering (e.g., Bousfield, 1953) and subjective organization (e.g., Tulving, 1962b). Both are characterized by a consistency of recall order. In clustering, organization is inferred from a consistency between the grouping of items in recall and some predetermined grouping of items. In subjective organization, the consistency from which organization is inferred is between recall orders on successive recall trials. Although clustering and subjective organization are operationally distinct, it is assumed here that they reflect the operation of common processes. Clustering and subjective organization refer to recall-order phenomena which share an essential characteristic: Nonrandomness of emission order in free recall. With respect to subjective organization, nonrandomness of recall order may provide the core of an argument against an associative interpretation, since the recall list involves "unrelated" materials, and presentation procedures insure that specific sequential adjacencies do not recur during input. Similarly, demonstrations of clustering in the absence of interitem associations may be viewed as damaging to an associational position (e.g., t~oberts, 1968). One task set for the associative theorist is to account for nonrandom recall sequences in the free recall of items that are not associatively related (as determined from normative data). It is argued here that Ss actively associate items during the study and test phases of a free-recall task, and consequently items that are not associatively related prior to learning may be associated during the learning task.
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factors which may determine specific contiguous relations among items, and it should be emphasized that these factors operate during recall trials, as well as during study trials. Thus, recall order is viewed as being associatively determined, and superordinate systems (e.g., Bousfield, 1953), coding activities (e.g., Cohen, 1966), organizational rules (e.g., Pollio, Kasschau, & DeNise, 1968), etc., function such that "unitized" items are processed contiguously. No attempt is made to explain the development of pre-experimental habits responsible for specific items appearing contiguously. The application of an association principle to free-recall phenomena is not new (Corer, 1965, 1967; Deese, 1959a, 1959b, 1960). Wood (1969) referred to the development of sequential associations in describing the nature of organization in free-recall learning. Generally, interpretations of clustering in free recall have emphasized either interitem associations or higher-order memory codes (e.g., category names). Although a considerable amount of effort has been devoted to contrasting these two interpretations (e.g., Allen, Puff, & Weist, 1968; Bousfield, Steward, & Cowan, 1964; Cofer, 1966, Cofer, Bruce, & Reicher, 1966; Marshall, 1967a, 1967b), it has been argued that attempts to distinguish between associative and coding mechanisms of clustering are of little utility (Cofer, 1965; Tulving, 1968). The present extension of the contiguity principle also regards such a distinction as unnecessary. The content of memory units is viewed here as being determined by specific contiguity relations of list items, and both direct associations and "coding" activities may operate to influence the specific contiguity relations experienced. FACTORS DETERMINING CONTIGUITY RELATIONS
Nominal Input Order There are two components of the free-recall procedure during which Ss are exposed to list
items: the study trial and the recall trial. The order that items are presented to Ss provides one source of specific contiguity experiences, and the order that items are recalled provides a second source of specific contiguity experiences. If contiguity of experience influences organization at recall, then one may expect substantial agreement between corresponding input orders and output orders, and between successive output orders. Agreement between successive output orders has been well substantiated and describes the empirical phenomenon of subjective organization (e.g., Tulving, 1962b). However, with standard free-recall procedures there is generally very little agreement between input order and output order (Asch & Ebenholtz, 1962). Asch and Ebenholtz varied input order across trials and considered only the immediately preceding input order when assessing the agreement between input order and output order. Repetitions of specific input orders across trials may be expected to strengthen sequential associations, consequently the probability that output orders will agree with input orders ought to be higher when the same input order is used on all trials, compared to the standard procedure of varying input orders across trials. Although Waugh (1961) and Stimmel and Stimmel (1967) failed to demonstrate that constant input order across trials enhanced recall, Lachman and Laughery (1968) and Jung and Skeebo (1967) reported such facilitation. Jung and Skeebo also found that output order following a constant input order changed over trials, becoming more like recall orders typical in serial learning. Mandler and Dean (1969) presented Ss with 16 word free-recall lists. They included a variety of presentation procedures, but of immediate concern here was their variation of input order. The words were presented in a constant order or in a different random order on each trial. Recall scores and subjective organization scores were enhanced following constant input order. Further, there was substantial agreement between the input order and the
CONSISTENCY OF RECALL ORDER
output order for the constant order conditions. In addition to constant input order, the agreement between input order and output order is high when the length of the free-recall list falls within the immediate memory span (e.g., Bousfield & Abramczyk, 1966; Jahnke, 1965) and when the list order approximates language structure (e.g., Deese & Kaufman, 1957; Postman & Adams, 1960). It has been argued that because the freerecall p a r a d i g m " . . , involves presentation of material completely free from any sequential redundancy, such redundancy or organization in subject's recall cannot be attributed to the input material" (Tulving, 1962b, p. 345). There is little agreement between input and output orders of unrelated words with standard freerecall procedures, but this poses a serious difficultyfor the contiguity position only if two assumptions are tenable: (a) the order that items in a free-recall list are presented to Ss faithfully reflects the sequential order in which they are processed, and (b) varyinginput orders across trials in a random fashion guarantees that sequential redundancy during input cannot be attained. In the following sections an alternative possibility will be explored, viz., that there is a discrepancy between the order in which items are presented to S (nominal input order) and the order in which presented items are processed in memory (functional input order). The implication of this possibility is that only agreement between output order and functional input order is critical to the contiguity position, and merely comparing nominal input order and output order has little relevance to an evaluation of the contiguity principle.
Functional Input Order It is not unreasonable to assume that even in a simple learning experiment human Ss may act upon their environment and alter it in some way. For example, in paired-associate learning Underwood (1963) distinguished between the nominal stimulus and the functional stimulus. That is, Ss may alter the
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stimulus term (e.g., use only the initial letter) and form an association between this modified stimulus and the response. Cooper and Pantie (1967) have made a similar distinction with respect to an S's use of study time. It is suggested here that Ss may act upon list items as they are presented during a free-recall task, thereby processing items in a sequential order not identical to the nominal presentation order. Any departure on the part of Ss from the rote, mechanical repetition of exactly what is presented to them may disrupt the nominal order of processing information. For example, it is reasonable to assume that Ss rehearse items during study trials, and further, that Ss do not necessarily rehearse items in the order that they are presented (Mechanic & Mechanic, 1967). That is, if the items check, force, body, and desert are presented in that order, an individual S may rehearse check when body appears. Thus, the nominal input order is check, force, body, desert, but the functional input order is check, force, body, check, desert. The contiguity relations assumed from the nominal input order differ from the functional contiguity relations. Ekstrand (1966) has pointed out that comparisons of stimulus recall and response recall in pairedassociate learning do not provide fair tests of associative symmetry if there is a discrepancy between the nominal stimulus and the functional stimulus. It is also true that agreement between input orders and output orders in free recall does not provide a fair test of the contiguity principle if there is a discrepancy between the nominal input order and the functional input order. Varying nominal input order across trials does not guarantee that the list is free from functional sequential redundancy. Rehearsal. Rehearsal of list items during study trials and during test trials is one major activity which may alter the nominal contiguity relations among list members. Procedures which minimize the opportunity for rehearsal. ought to slow the development of organization and lead to organization in recall which more
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closely follows nominal input order. Rehearsal prevention activities during study trials have been shown to depress recall (Allen, 1968; Glanzer & Meinzer, 1967) and subjective organization (Allen, 1968). Constant input order across trials, compared to varied input orders, may be expected to increase the stability of rehearsal order. The development of organization in free recall is enhanced following constant input orders (Mandler & Dean, 1969). Recall-trial activity may be an important factor in multitrial free recall. The recall trial cannot be considered as only providing measurement without contaminating future measurement (Lachman & Laughery, 1968; Tulving, 1967). When Ss are allowed to study an ordered array of words, they show a strong tendency to reproduce the words in the same order as they appeared on the study sheet (Wallace, 1969). It is reasonable to assume that Ss rehearse items in an order that corresponds with spatial location on recall sheets (e.g., in a top-to-bottom order or in a left-to-right order). The rehearsal activity serves to strengthen and develop associations between items recalled in close temporal proximity. Subjective organization is defined by consistency in ordering items across successive recall trials, thus allowing S free study of a preceding recall order ought to enhance organization scores. When conditions are arranged so that rehearsal order (spatial location on recall sheets) does not correspond to the temporal recall order, the development of organization is disrupted (Wallace, 1969). Studies of organization in free recall have given little attention to learning activities that transpire during recall trials. If rehearsal during recall trials is important to the emergegence of organized recall, then the development of organization ought to be relatively slow when the training procedure consists of repeated study trials without interspersed test trials, and it ought to be facilitated following a training procedure involving repeated test trials separated by occasional study trials. It
may be noted that this latter expectation that organization should increase across test trials not separated by a study trial represents a prediction of a discrepancy between recall and organization, since recall has been demonstrated to decline slightly across test trials not separated by a study trial (e.g., Tulving, 1967). It seems reasonable that the more time S is allowed for recall, the greater is his opportunity to review his recall, and allowing S to write his responses during recall makes it easier for him to review previous contiguous relations. The majority of studies concerned with multitrial free recall have utilized writtenrecall procedures and generally allowed Ss ample time for recall (e.g., Bousfield & Cohen, 1953; Paivio, Rogers, & Smythe, 1968; Puff & Bousfield, 1967; Puff & Hyson, 1967; Tulving, McNulty, & Ozier, 1965). There is evidence that organization develops with oral-recall methods (Mayhew, 1967; Segal & Mandler, 1967; Tulving, 1964; Tulving & Osler, 1967), but organization in recall is depressed when recall is oral and when recall duration is relatively brief (Wallace, 1969). There have been efforts to prevent Ss from studying their recall sheets by not allowing them to view previous responses (Abramczyk & Bousfield, 1967; Bousfield & Abramczyk, 1966). However, contrary to expectations based on the present contiguity orientation, Allen (1968) found that covering responses during recall had little effect on recall or organization scores, Mediating responses. The presentation of a verbal unit may elicit a variety of implicit responses (Bousfield, Whitmarsh, & Danick, 1958; Mandler, 1954), and these implicit responses may function to bring temporally disparate items into contiguous positions. Underwood (1965) presented Ss with a long series of words and asked them to indicate whether each word had appeared earlier in the series. Critical test words presented for the first time, but related to earlier list words, elicited more "false positives" (Ss reported
CONSISTENCY OF RECALL ORDER
having seen them earlier) than appropriate control words. Underwood argued that when the related words were presented early in the list, the corresponding critical test words were elicited implicitly as associational responses. Thus, each critical test word acquired some presentation frequency, which increased the difficulty of correctly identifying it as a first occurrence. The occurrence of such mediating responses provides a second way in which contiguity relations within a free-recall list may be altered from the nominal input order. For example, assume that during a study trial the word man appears early in the list. Upon the presentation of this item, S responds implicitly with woman. Assume further that the word woman actually appears later in the list, at which time S responds implicitly with man. The implicit response mechanism has placed in contiguous positions items which were separated during the study trial by several other items. In this fashion, implicit responses may directly modify nominal input contiguity relations. The mediating mechanism may also operate indirectly by initiating contiguous rehearsal of list members. That is, the mediating response need not occur directly in the list, but if it links list members, and they in turn are rehearsed together, it has served to establish the contiguous occurrence of specific list members that may be temporally spaced. If the word canary appears at one position in a free-recall list and S responds implicitly with yellow and the word banana appears at some position removed from canary and S again responds implicitly with yellow, this second implicit response may lead to the implicit response (rehearsal) of canary by means of a backward association (cf., Wood & Underwood, 1967). Thus, two words may be functionally contiguous if they elicit a common implicit response. The preceding examples of direct and indirect mediating responses have utilized agsociative implicit responses. However, there
63
is no intention of restricting the present analysis to conventional associative responses. Two smudges on the memory-drum tape may serve to bring items into contiguous positions, provided that S responds appropriately to the smudge stimulus. Any conceptual basis for grouping items may be used by S, provided that the critical relationships among stimuli are recognized. It follows from the preceding arguments that concept identification is an important component of organization in free recall. Ignoring the problem of the original formation of concepts, it can be stated that variables which facilitate concept identification, and that can be translated to the free-recall situation, ought to increase the development of organization. Underwood (1952) has stated: "For the perception of relationships among stimuli the needed assumption is that the appropriate responses to these stimuli be contiguous" (p. 211). Variations in procedures expected to bring common implicit responses into closer continguity ought to enhance organization in free recall. Blocked or constrained presentation order during which all members from one category are presented, and then all members of a second category are presented, etc., has been shown to facilitate both clustering and recall, compared to random presentation orders (e.g., Cofer et al., 1966; Tulving, 1965; Weingartner, 1964). The facilitating effect on recall of presenting low-strength associates in a list decreases as the number of items intervening between the presentations increases (Glanzer, 1969). Puff (1966) demonstrated that both recall and organization increased following an increase in the number of times words immediately preceded other words from the same category. Presumably, blocked presentation order increases the likelihood that the common implicit response to related items will occur several times in close temporal proximity, although Ss receiving blocked input order also have the advantage that nominal input contiguity corresponds to the predetermined basis for organization.
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However, Puff (1966) has indicated that of the contiguity principle make such a agreement with nominal input order cannot uniprocess model general enough to incoraccount for all of the advantage of blocked porate the wide assortment of clustering input. relations. Procedures designed to facilitate or interfere In summary, mediating responses serve to with the implicit-response mechanism ought alter the functional contiguity relations among to alter organization in free recall. For example, a list of words. They do this directly if the the stronger the natural relations between list implicit response is also a list member or items and the common associative response indirectly by priming contiguous rehearsal of which links them together, the greater the list members linked by a common implicit likelihood that these items will be brought response. The implicit response does not have into contiguous relations. The amount of to be an associative response, it need only be a clustering in free recall has been shown to be common "tag" for two or more items. If S can directly related to the strength (based upon get from this tag the second time it occurs as an normative data) of common associative re- implicit response to the first item for which he sponses (e.g., Bousfield, Cohen, & Whit- used the tag, then the two items have been marsh, 1958; Bousfield & Puff, 1964; Bous- brought into contiguous positions. When field, Steward, & Cowan, 1964; Jenkins, overlapping conceptual relations among list Mink, & Russell, 1958; Matthews, Marcer, & members exist, it is expected that the most Morgan, 1964). Increasing the number of salient response tendencies will determine the trials in free recall may be expected to increase specific organizational structure observed the strength of common associative responses, (Lambert, Ignatow, & Krauthamer, 1968). it and both clustering (e.g., Bousfield & Cohen, should be noted that while the mediating1953; Robinson, 1966) and subjective organi- response mechanism extends the applicability zation (e.g., Tulving, 1962b) have been shown of an association-by-contiguity principle, it to increase across trials. It has been suggested also may weaken the principle by making it too that implicit responding does not occur general. That is, if clustering fails to occur on readily under conditions of incidental learning, some predetermined basis, such as form class and with this procedure the amount of cluster- (Cofer & Bruce, 1965; Koplin & Moates, ing in free recall appears to be reduced 1968) or common decoding rules (Underwood (Wallace & Calderone, 1969). It has also been & Erlebacher, 1965), one may simply argue suggested that mediation is related to intellec- that the appropriate implicit responses did not tual development of Ss (e.g., Kendler, occur. We know the appropriate implicit Kendler, & Wells, 1960; Reese, 1962), and responses occurred when we observe clusteramount of clustering has been shown to be ing! However, the circle can be broken by directly related to developmental level of Ss examining clustering in cases where the critical (Bousfield, Esterson, & Whitmarsh, 1958; relationships can be dimensionalized, or in cases where variables that influence the obGerjuoy & Spitz, 1966). Bousfield and Bousfield (1966) identified 15 viousness of the basis for grouping items can be unifying characteristics found among items identified (e.g., clustering must be more grouped together in recall. These character- pronounced with high-strength associates than istics varied from simple associative relations with low-strength associates). Merely explorto more complex linguistic factors. Does the ing whether a particular relationship among existence of different characteristics relating items will provide a sufficient basis for clusterclustered items force acceptance of a multiple- ing will have little relevance to an evaluation process theory ? It is argued here that it does of the present extension of the contiguity not. The rehearsal and mediating extensions principle.
CONSISTENCY OF RECALL ORDER
ANOVERVIEW The arguments raised in the present discussion attempted to describe activities of Ss engaged in a free-recall task. The present proposal reflects the view that a description of the activities of Ss engaged in free recall will facilitate our understanding of the product of those activities, viz., organized recall. The rehearsal and mediating activities of Ss described here are influenced by characteristics of the stimulus materials and experimental procedures. It was reasoned that the rehearsal and mediating activities result in repetitions of specific contiguity experiences (specific list members are practiced together regularly). It is known that contiguity provides a sufficient basis for the development of associations. Also, it is known that associatively related items cluster in recall protocols, presumably because the recall of one associate cues or enhances the probability of the immediate recall of other list associates. Demonstrations of"nonassociative" organization in free recall are viewed here as reflecting the operation of an associative process. Recently, Slamecka (1968) presented evidence that recall is not enhanced when subsets of the list are presented as cues for Ss. Freund and Underwood (1969) demonstrated similar results with a variation in testing procedures. Such evidence may be construed as damaging to the present contiguity interpretation. However, Allen (1969) has argued that some organization must develop before one may expect facilitation from a subset of list items that serve as cues, and one needs to identify the specific organizational structure to maximize facilitation from such cues, i.e., if S organizes a list of 10 words into five pairs, maximal facilitation from cuing would result by presenting one member of each pair as a cue word. Allen demonstrated that cuing facilitated recall under conditions designed to optimize the cuing effect. The present extension of the contiguity principle has been suggested as an alternative way of viewing "organizing" behavior in free 3
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recall. Current theoretical viewpoints have been summarized in a recent review by Shuell (1969). These theoretical statements have focused on one or more of the grouping principles (e.g., category codes, direct associations, etc.) in accounting for organizational phenomena. As Shuell suggests, it does not appear that all of the relevant data can be incorporated within a single grouping principle. The present extension of the contiguity principle emphasizes that all grouping relations may accomplish the same end, viz., the contiguous experience of specific items. The advantage of such thinking is that a single mechanism can then account for grouping items in recall. Most of the existing data on organization in recall fit this contiguity model, and the model generates additional predictions. In general, procedures that enhance contiguity experiences must facilitate organization, and procedures that disrupt contiguity experiences must interfere with organization. Positive results from such research can be incorporated easily within other theoretical frameworks, provided that they acknowledge that instance contiguity is sufficient for organizational units to develop. Negative data from such research is only damaging to the contiguity view. The research reviewed in the present report is consistent with expectations from the contiguity position (with the exception of Allen's (1968) data on output viewing conditions). It would be difficult to contrast empirically the present notion with existing views. The reason for this difficulty is that most theorists may be willing to accept contiguity (as proposed here) as one mechanism of organization. The present discussion represents an attempt to describe how contiguity may be basic to a wide range of demonstrations of organized recall. It seems reasonable that the mediating and rehearsal activities described here take place during input and output phases of a free-recall task. It remains to be verified that the consistent contiguity experiences presumed to result from such activities produce organized recall.
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As mentioned earlier with respect to clustering, the real danger concerning a unitizing principle like the one proposed is that it is so general that it incorporates everything without the possibility of being refuted. The rehearsal and mediation extensions proposed in this report enable the associative theorist to account for data that could not be handled within the limitations set by restricting associations to pre-experimental language habits or those that may develop during the experiment from nominal input-order contiguity. While these extensions may weaken the principle, it has been argued here that the contiguity principle is falsifiable. REFERENCES ABRAMCZYK,R. R., & BOUSFIELD,W. A. Sequential ordering in repeated free recall as a function of interitem associative strength. Psychological Record, 1967, 17, 183-192. ALLEN, M. Rehearsal strategies and response cueing as determinants of organization in free recall.
Journal of Verbal Learning and Verbal Behavior, 1968, 7, 58-63. ALLEN, M. M. Cueing and retrieval in free recall. Journal of Experimental Psychology, 1969, 81, 29-35. ALLEN, M., PUFF, C. R., & WEIST, R. The effects of associative and coding processes on organization in free recall. Journal of Verbal Learning and Verbal Behavior, 1968, 7, 531-538. ASCH, S. E., & EBENHOLTZ,S. M. The process of free recall: Evidence for non-associative factors in acquisition and retention. Journal of Psychology, 1962, 54, 3-31. BOUSFIELD,A. K., & BOUSEIELD,W. A. Measurement of clustering and of sequential constancies in repeated free recall. Psychological Reports, 1966, 19, 935-942. BOUSFIELD,W. A. The occurrence of clustering in the recall of randomly arranged associates. Journal of General Psychology, 1953, 49, 229-240. BOUSFIELD, W. A., & ABRAMCZYK,R. R. Sequential ordering in repeated free recall as a function of the stimulus word list. CanadianJournalofPsychology, 1966, 20, 427-434.
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ROBINSON, J. A. Category clustering in free recall Journal of Psychology, 1966, 62, 279-285 SEGAL, M. A., & MANDLER, G. Directionality and organizational processes in paired-associate learning. Journal of Experimental Psychology, 1967, 74, 305-312. SHUELL,T. J. Clustering and organization in free recall Psychological Bulletin, 1969, in press. SLAMECKA, N. J. An examination of trace storage in free recall. Journal of Experimental Psychology, 1968, 76, 504-513. SPEAR, N. E., EKSTRAND,B. R., & UNDERWOOD,B. J. Association by contiguity. Journal of Experimental Psychology, 1964, 67, 151-161. STIMMEL, D. T., & STIMMEL, N. S. Free recall as a function of intralist similarity and order of presentation constraints. Psychological Reports, 1967, 21,541-544. TULVlNG, E. The effect of alphabetical subjective organization on memorizing unrelated words. Canadian Journal of Psychology, 1962, 16, 185191. (a) TULVING, E. Subjective organization in free recall of "unrelated" words. Psychological Review, 1962, 69, 344-354. (b) TULVING, E. Intratrial and intertrial retention: Notes towards a theory of free recall verbal learning. Psychological Review, 1964, 71, 219-237. TULVING, E. The effect of order of presentation on learning of "unrelated" words. Psychonomic Science, 1965, 3, 337-338. TULVING, E. The effects of presentation and recall of material in free-recall learning. Journal of Verbal Learning and Verbal Behavior, 1967, 6, 175-184. TULVING, E. Theoretical issues in free recall. In T. R. Dixon and D. L. Horton (Eds.), Verbal behavior and general behavior theory. Englewood Cliffs, New Jersey: Prentice-Hall, 1968. TULVING, E., McNULTY, J. A., & OZIER, M. Vividness of words and learning to learn in free-recall learning. Canadian Journal of Psychology, 1965, 19, 242,-252.
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(Received August 30, 1969)