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The development of the understanding of causality in infancy
INFANT BEHAVIOR AND DEVELOPMENT 6, 201-210 (1983)
The Development of the Understanding of Causality in Infancy* MIRIAM E. SEXTON University of Massachusetts Medical School Causal development was examined from a Piagetian perspective with respect to the infant's understanding of other persons as autonomous causal agents. It was predicted that the child's attempts to influence others to act would differ depending on the level of causal understanding. Fifty-four infants, ages 11, 17, and 23 months, participated in six experimental episodes in which various events were caused by the mother, by the examiner, and seemingly by neither of the persons. As predicted, infants at the fourth stage of causal development seldom turned to others to induce them to act and instead attempted to solve the problems through their own activity. By the end of the sensorimotor period infants were capable of mentally representing the cause and effect sequence and turned largely to others on the basis of their agency in causing an event to occur. The results substantiated Piagefs theory of causality during infancy and provided support for the posited relationship between the development of causality in relation to inanimate objects and the understanding of the concept of agency.
causality
Piaget
Piaget (1954) discussed development in understanding of causality as a major component in the infant's construction of reality during the sensorimotor period and described a sequence of six stages to characterize this development. Through the third stage the infant behaves as if the universe were seen not as a web of causal sequences, but as a collection of events arising in extension of her actions. During the fourth stage the necessity of spatial contact in causal action is recognized. With the fifth stage the infant begins to appreciate that her activity is limited by the effects of causes independent of herself, and she becomes only one cause among other causes. Finally, during the sixth stage, the child can mentally represent causal sequences and can recognize causes outside of her immediate perceptual field. Although Piaget's theory has been a prominent influence on developmental studies, scant research has been done regarding his ideas on the development of causal understanding in infancy. The little research that has been done has taken the form of attempts to devise scales in order to replicate Piaget's proposed sequence or to establish a relationship between development in causal understanding and some other developmental milestone. Uzgiris and Hunt (1975) devised a scale to assess * This study is based on a dissertation done under the direction of lna C. Uzgiris and submitted to the Department of Psychology at Clark University in partial fulfillment of the requirements for the Ph.D degree. Professor Uzgiris' invaluable support and guidance are gratefully acknowledged. I would also like to thank Robert Baker and Leonard Cirillo for their assistance with this project. Correspondence and requests for reprints should be sent to Miriam E. Sexton, Child Development Service, University of Massachusetts Medical School. Worcester, MA 0160.5.
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the way infants attempt to cause a reoccurrence of various physical events and concluded that there is a developmental progression in practical causal knowledge. Goulet (1974) constructed a causality scale that distinguished between behaviors regarding material causes and behaviors with respect to persons as causal agents. Using this scale he substantiated a developmental progression in causal understanding and also found that causality attributed to persons was either at a higher level or paralleled causality attributed to inanimate objects for all but two subjects in the sample. This suggests that a distinction between understanding of causal relations and of personal agency may be worth maintaining. A "frustration" situation was employed by Van Lieshout (1975) to study infants' use of other persons as causal agents but without independently assessing the infant's stage in causal development. The reactions of infants to the introduction of a barrier by their mothers between them and a toy were observed at 18 months and again at 24 months. It was found that infants either made independent efforts to reach the toy or attempted to obtain their mothers' help; moreover, the children directed less negative affect toward the toy or barrier and more positive overtures toward the mother at age 2 than at 18 months. He interpreted this result as reflecting significant changes in the child's ability to cognitively reconstruct the sequence of events involved in the barrier problem and to understand the mother's instrumental value. He argued that the older children were better able to understand that it was the mother who put the toy behind the barrier and that she would, therefore, know how to get it out. However, Van Lieshout's interpretation goes somewhat beyond the results of his study. The mother may have been used as an instrument by the 2-year-olds more frequently because of their greater experience with the mother's efficacy rather than because they better understood that she was the causal agent for setting up the barrier. The utilization of more than one agent is needed to ascertain whether the child has only a global understanding of another person as agent or whether she has the understanding of a specific person causing a particular event. In the present study, therefore, infants were shown events produced by the examiner, as well as by the mother, and, also, seemingly noncaused events. One of the goals of the present study was to trace the change in the infants' use of other persons as agents during the second year of life. Harding and Golinkoff (1979) attempted to relate infants' stage in causal development with their way of communicating a desire to the mother. The infants were exposed to two "frustration" episodes during which the mother caused events to occur that the infants could not replicate on their own. They found that only infants classified at Stage V of causal understanding used intentional vocalizations, that is, made eye contact with the mother by gesturing or looking while vocalizing. In the present study various behaviors of infants toward others as agents were examined. The expectation was that infants through the fourth stage of causal development would not treat other persons as agents because of their conviction of the necessity for self-activity in causing events to occur. In the fifth stage, when the infant begins to appreciate the autonomous causal powers of others, it was expected
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that the infants might attribute independent agency to only a few individuals, such as the mother, because of their greater concrete experience with the mother and their global understanding of causal connections. The child may appreciate the ability of others to act independently, but have little understanding of the actions of others as causes for specific events. With the beginning of representational thought during the sixth stage of development, it was expected that infants would better understand the cause and effect sequence of events and would be better able to conceptualize the involvement of a particular person in causing an event. Another goal of the present study was to examine the relationship between a child's understanding of the causes of physical events and her understanding of the agency of persons. For this purpose, several situations involving spectacles produced by inanimate objects were presented to the infants. The infants' stage of causal development with respect to inanimate objects was determined and related to their appreciation of the agency of others.
METHOD Subjects The subjects were 54 infants, equally distributed among the age groups of 11, 17, and 23 months. These ages were selected on the basis of previous research which suggested that these age groups might correspond to the fourth, fifth, and sixth stages of causal development. The sample consisted of equal numbers of boys and girls in each age group. Four additional infants were seen and then excluded from the sample due to lack of cooperation during the session.
Procedure The first portion of the experimental procedure consisted of six episodes in which various events, expected to be highly salient for infants, were alternately caused by the mother, by the examiner, or seemingly by neither person. Three of these events were regarded as "facilitative," in that the toy remained accessible to the child after the event occurred. The other three episodes were regarded as "prohibitive," in that the toy became inaccessible through the use of a barrier or obstacle after the crucial event. Both types of events were included to provide a broader array than in previous studies, which focused solely on "prohibitive" episodes. In each episode the child was able to examine the toy before the critical event centering on that toy occurred. The episodes were designed so that the infants would be unable to successfully cause the event to reoccur by themselves so as to enhance the likelihood of their turning to the two adults present. To further emphasize the agent's causative role, she produced the spectacle three times, at 1 minute intervals. The mothers were instructed not to comply with any requests by the infants to reactivate the toys. During the first episode, the mother activated a battery operated singing bird. In the second episode, a rubber ball was raised outside the infant's reach. This was accomplished by suspending the ball from the ceiling by a thread which was at-
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tached to a reel located behind the experimenter's back. This enabled her to surreptitiously raise the ball by winding the thread on the reel behind her back so that neither she nor the mother appeared to cause the ball to rise. During the third episode, the examiner activated a battery operated fire engine. In the fourth episode, the mother activated a battery operated drumming bear and then placed it in the center of a playpen so that the child could see, but not reach, the toy. During the fifth episode, a pecking chicken toy was activated so that the chicken's heads bobbed up and down. This was accomplished by pulling a string connected to the chicken's heads which extended from underneath the base. The string was pulled by the examiner, while seated at a distance from the toy, so that neither person was touching the toy when activated. In the sixth episode, the examiner placed a Slinky inside a transparent Plexiglas box so that the child could see but not reach the toy. In sum, this portion of the procedure consisted of two episodes in which the mother caused an event to occur, two episodes in which the examiner caused an event to occur, and two episodes in which neither person appeared to cause the event which occurred. One half of the sample was presented with the toys as described. The remaining one half of the sample was presented with the last three toys first and the first three toys last. This procedure permitted variation in the order of toy presentation while insuring that the same agent did not cause any two consecutive events. During the second portion of the experiment the infant's level of causal development was ascertained in situations concerned with the functioning of objects. Four items selected from the existing scales (Escalona & Corman, 1968; Goulet, 1974; Uzgiris & Hunt, 1975) pertinent to the fourth through sixth stages of causal development were presented. The Oscar the Grouch toy had a long cord to which the bulb was attached; when the bulb, which was hidden underneath the table, was squeezed, Oscar jumped up from his trash can. The Donald Duck toy had buttons located on either side of the base of the toy; when the buttons were pressed, Donald jumped over the ladder. The train had a large key on the side, which, when wound, moved the train. The bottle of soap bubbles and wand were used to demonstrate how to make soap bubbles. Children's responses to these items were used to assign them to a stage of causal understanding. Not all items tapped all stages; the items were selected so that three responses were scorable for the fourth, fifth, and sixth stages. An action performed on the moving parts of a toy, such as attempting to move the train by turning the wheels, was scored as a Stage IV response. Appropriate activation of a toy was scored as a Stage V response. Searching for the hidden cause of a spectacle was scored as a Stage VI response. The criterion for assignment to a specific stage was achievement of two out of the three possible responses at a particular level.
Scoring The examiner recorded the behavior of the 54 infants. For 14 children, an independent observer located behind a one-way mirror also recorded each infant's behavior
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to establish the reliability of the scoring. For the six experimental episodes interjudge reliability was 80%. For the four causal scale items interjudge reliability was 91% for the individual items, and 93% for stage placement. Stage placement for the child, about whom there was initial discrepancy, was decided by agreement between the judges. For the six experimental episodes the infant's behaviors were scored using the following categories: showing, offering, or pointing to the toy to obtain assistance, attempts to take the mother or the experimenter to the toy or barrier, verbal requests for assistance, and crying, emotional upset, or angry behavior directed at the mother or examiner. An overture was scored anytime one of these behaviors occurred and it was noted at whom it was directed. RESULTS
The Causality Items Examination of the data revealed a distribution of infants among the fourth through sixth stages of causal development in accord with the sequence suggested by Piaget. All I 1-month-old infants gave predominantly Stage IV responses. Of the 17-monthold subjects, 3 were classified at Stage IV, 12 at Stage V, and 3 at Stage VI. Among the 23-month-old subjects, 4 gave predominantly Stage V responses and 14 gave predominantly Stage VI responses.
Use of Agents Use of agents was assessed by the frequency of overtures to the two adults present. Preliminary analyses revealed no significant differences in frequency of overtures on the basis of sex, the order of episode presentation, or facilitative versus prohibitive episodes. Nonparametric statistics were selected for the analyses because the scores for the sample did not correspond to a normal distribution due to the large number of zero scores in the frequency of overtures for the 11-month-old group. A JonckheereTerpstra Test (Hollander & Wolfe, 1973) for the three groups showed that the frequency of overtures to other persons increased with age (z = 6.71, p < .001) and causal stage (z = 6.52, p < .001). The median frequencies of turns for the groups are presented in Table 1. Wilcoxon Matched-Pairs Signed-Ranks Tests were performed for the two oldest groups to assess whether they turned differentially to other persons. When the frequency of overtures to the mother was analyzed using the combined number of overtures to her on the two mother-caused episodes and on the two examiner-caused episodes as matched pairs, it was found that the 23-month-olds turned to the mother significantly less on the examiner-caused episodes (T = 15, p = < .01), whereas the 17-month-old group's rate of turning for assistance did not significantly differ for the two types of episodes. The magnitude of the difference between the two groups, as measured by a Mann-Whitney U Test, was also significant (U = 89.5, p < .025).
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TABLE 1 Median Frequencies of Overtures By Age and Causal Stage
Group Age 11 months 17 months 23 months Causal Stage
Median Frequency of Overtures 0.00 18.00 49.50
Stage IV
0.00
Stage V Stage VI
26.00 48.00
The frequency of overtures during the mother-caused and the seemingly noncaused episodes was also examined. When the rates of overtures on the mothercaused and the non-caused episodes were analyzed using Wilcoxon Tests, it was found that both the 23-month-olds (T = 5, p < .01) and the 17-month-olds (T = 17, p < .01) turned differentially on the basis of whether the event was caused or noncaused, with both groups turning for assistance to the mother significantly less on the non-caused episodes. The magnitude of the difference in the frequency of overtures in these two types of episodes was also significant when the two groups' scores were analyzed using a Mann-Whitney U Test (U = 93, p < .025), with the 23-month-old group turning differentially to the mother on the basis of whether an event was mother-caused or non-caused to a greater extent than the 17-month-old group. When the frequency of overtures to the examiner on the examiner-caused and the mother-caused episodes was analyzed, it was found that both the 23-month-olds (T = 0, p < .01) and the 17-month-olds (T = 3.5, p < .01) turned to the examiner significantly more on the examiner-caused episodes. The difference between the two groups in this respect was also significant (U -- 67.5, p < .01), with the 23month-old group turning differentially to the examiner on the basis of whether an event was examiner-caused or mother-caused to a greater extent. The frequency of overtures to the examiner for the examiner-caused and the apparently non-caused events was also analyzed. Wilcoxon Tests showed that both the 23-month-olds (T = 7, p < .01) and the 17-month-olds (T = 4.5, p < .01) turned to the examiner significantly less on the non-caused episodes. The difference in the magnitude of frequency between the two groups was also significant (U = 84.5, p < .01), with the 23-month-old group turning differentially to the examiner on the basis of whether an event was examiner-caused or non-caused to a greater extent. The median frequencies of overtures to the mother and to the examiner for the mother-caused, examiner-caused, and non-caused episodes are summarized in Table 2.
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TABLE 2 Median Frequencies of Overtures to the Mother and to the Examiner
Ep~ode Group
Mother-caused Episodes
Examiner-caused Episodes
Non-caused Episodes
Overtures to the Mother 17-month-old 23-month-old
8.95 19.89
4.67 8.39
3.34 6.28
Overtures to the Examiner 17-month-old 23-month-old
.78 1.45
3.17 16.39
.56 2.78
Use of Agents by Causal Stage Reanalysis of the data by causal stage rather than age revealed that the Stage IV group, similarly to the 11-month-old group, seldom turned to either of the adults for assistance during any of the episodes. However, the Stage V and Stage VI groups' frequencies of overtures were more similar to each other than when the data were analyzed by age. Both the Stage V and Stage VI infants turned to the mother more frequently on the mother-caused episodes and less frequently on the non-caused episodes, with the difference between the two groups not significant in this respect. Both groups also turned to the examiner more frequently on the examiner-caused episodes and less frequently on the non-caused episodes. The difference between the two groups on the examiner-caused episodes was significant (U = 83.5, p < .05), with the Stage VI subjects turning differentially to the examiner on the basis of her agency in causing an event to a greater extent than the Stage V subjects, whereas the difference between the two stage groups on the non-caused events was not significant. DISCUSSION The results of this study confirmed many of the initial expectations. As predicted, the frequency of overtures to others to get them to act for the infant increased dramatically with age and stage of causal development. Infants among the l lmonth-old group seldom turned to others to induce them to act. They attempted to solve the problem themselves by manipulating, shaking, or banging the toys or barriers. When this was unsuccessful in producing the desired effect, they quickly gave up and became interested in some other object in the room. The behavior of these infants was very similar to that described by Harding and Golinkoff (1979), whose Stage IV infants seldom directed vocalizations toward the mother and who
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banged a toy during a frustration episode rather than handing it to their mothers as a means of obtaining help. As predicted, the 23-month-olds turned to the mother significantly more often on the mother-caused than on the examiner-caused episodes, whereas the 17-montholds turned predominantly to the mother after both types of events• The oldest group also turned differentially to the examiner on the basis of whether an event was examiner-caused or mother-caused to a significantly greater extent than the intermediate group. Thus, the oldest group appeared to have a better understanding of the examiner's agency, as it more clearly discriminated between these two types of episodes. Differing frequencies of overtures on the person-caused and seemingly noncaused episodes were also found. The 23-month-olds turned differentially to the mother and to the examiner on the basis of whether an event was person-caused or non-caused to a significantly greater extent than the 17-month-olds. Thus, the oldest group better understood when a person had caused a particular event to occur and turned less frequently to implore the mother or the examiner to act on the apparently non-caused episodes. One interesting observation was that many of the 23-month-old subjects, after once ascertaining that a problem was too difficult, refused to manipulate the toy or barrier any further and instead directed their efforts exclusively at attempting to induce the adults present to recreate the desired event. An adult's refusal to comply with the infant's requests produced increasingly vigorous and persistent overtures from many of the infants and sometimes culminated in angry outbursts, during which they cried and threw themselves on the floor. This finding was similar to that obtained by Van Lieshout (1975), who noted that the frequency of crying and expressions of anger increased with age and that infants showing frequent upset at the mother showed relatively little positive behavior toward the toy. The behavior of the oldest infants also suggests a limitation of the understanding of causal relations during the sensorimotor period. While the sixth stage marks the beginning of representational thought, the behavior of the oldest children suggests that their achievements were not yet completely dissociated from the concrete situations in which the events occurred. Thus, these infants did not appear to fully possess an abstract conceptual notion of the interchangeability of persons as agents, that is, that an event need not be reproduced by the person who initially caused it. This was reflected in their persistence in turning predominantly to the specific agent responsible for an event, despite that person's refusal to comply, rather than using both persons interchangeably. For the mother-caused episodes, only 8% of the children's overtures were directed to the examiner. For the examiner-caused episodes, the percentage was somewhat higher, with 39% of the children's overtures directed toward the mother. Taken together, these data suggest that the children at this stage continued to remain at least partially tied to the concrete cause and effect sequences involved and, therefore, directed their overtures primarily to the specific agent responsible for the event.
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The differing frequencies of overtures for the intermediate and oldest groups were not clearly identified when the data were reanalyzed by causal stage rather than age. Both groups acted more in accord with the expectations for the sixth stage. The exception was in the frequency of turns to the examiner; the Stage VI group turned to the examiner significantly more often than the Stage V group on the examiner-caused, than on the mother-caused, episodes. The results of the reanalysis of the data may perhaps be explained by examining the method employed to ascertain level of causal development. The stage of causal understanding was determined with respect to objects, and the 17-month-olds were predominantly at the fifth stage. It is possible that many of the infants in the 17-month-old group were already at the sixth stage of causal development in relation to persons while still scoring at the fifth stage in relation to objects. Piaget (1954) suggested that causality attributed to persons would precede that attributed to objects. Some support for this contention was provided by Goulet (1974), who found that person-related causality either preceded or paralleled that of object-related causality for all but two infants in his sample. The oldest age group studied by Goulet was 13 months. In his study all subjects among this age group were at the sixth stage of causal development in relation to persons, whereas only slightly more than half of the group were at the sixth stage in relation to objects. Thus, the results for the intermediate group may have been due to the age group selected, and the predicted behavior might have been more clearly observed if a younger age group had been chosen. These findings also suggest that person-related and object-related causality may follow parallel but somewhat different courses, with person-related causality more pertinent in assessing understanding of agency. Similar distinctions between person- and object-related achievements have been made with respect to other Piagetian concepts, such as object permanence (Bell, 1970). Two recent causality studies also support a similar conclusion. Carlson-Luden (1980) found that 10month-old infants demonstrated differential rates of pushing a knob which produced either a human or nonhuman event as a consequence. Similarly, Golinkoff and Harding (1980) found that infants at 16 months of age made distinctions between animates and inanimates, as measured by their behavioral and emotional responses to an incongruous event produced by an inanimate object moving unaided. Taken together, these studies suggest that a distinction should be made between personrelated and object-related causality, and that the examination of the developmental course of these two concepts is a promising area for future research. REFERENCES
Bell, S. M. The development of the concept of object as related to infant-motherattachment. Child Development, 1970,41, 292-311. Carlson-Luden, V. Infant causality: Is it the same for social and nonsocial events? In R. Golinkoff (Chair), Causality- The development of causality. Symposiumpresented at the International Conference on Infant Studies, Hartford, April 1980.
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Escalona, S. K., & Corman, H. H. Albert Einstein scales of sensori-motor development: Causality scale. Unpublished manuscript, Albert Einstein.College of Medicine, 1968. Goldberg, S., & Lewis, M. Play behavior in the year-old infant: Early sex differences. Child Development, 1969, 40, 21-31. Golinkoff, R. M., & Harding, C. G. The development of causality: The distinction between animates and inanimates. In R. Golinkoff (Chair), Causality: The development of causality. Symposium presented at the International Conference on Infant Studies, Hartford, April 1980. Goulet, J. Conception of causality and reactions to strangers. In T. Decarie (Ed.), The infant's reaction to strangers. New York: International Universities Press, 1974. Harding, C. G-, & Golinkoff, R. M. The origins of intentional vocalizations in prelinguistic infants. Child Development, 1979, 50, 33-40. Hollander, M., & Wolfe, D. A. Nonparametric statistical methods. New Yo, John Wiley and Sons, 1973. Piaget, J. The construction of reali~, in the child. New York: Basic Books, 1954. Uzgiris, I. C., & Hunt, J. McV. Assessment in infants: Ordinal scales of psychological development. Urbana, IL: University of Illinois Press, 1975. Van Lieshout, C. F. Young children's reactions to barriers placed by their mothers. Child Development, 1975, "16. 879-886.
18 May 1981; Revised 1 February 1982 •
The Development of the Understanding of Causality in Infancy* MIRIAM E. SEXTON University of Massachusetts Medical School Causal development was examined from a Piagetian perspective with respect to the infant's understanding of other persons as autonomous causal agents. It was predicted that the child's attempts to influence others to act would differ depending on the level of causal understanding. Fifty-four infants, ages 11, 17, and 23 months, participated in six experimental episodes in which various events were caused by the mother, by the examiner, and seemingly by neither of the persons. As predicted, infants at the fourth stage of causal development seldom turned to others to induce them to act and instead attempted to solve the problems through their own activity. By the end of the sensorimotor period infants were capable of mentally representing the cause and effect sequence and turned largely to others on the basis of their agency in causing an event to occur. The results substantiated Piagefs theory of causality during infancy and provided support for the posited relationship between the development of causality in relation to inanimate objects and the understanding of the concept of agency.
causality
Piaget
Piaget (1954) discussed development in understanding of causality as a major component in the infant's construction of reality during the sensorimotor period and described a sequence of six stages to characterize this development. Through the third stage the infant behaves as if the universe were seen not as a web of causal sequences, but as a collection of events arising in extension of her actions. During the fourth stage the necessity of spatial contact in causal action is recognized. With the fifth stage the infant begins to appreciate that her activity is limited by the effects of causes independent of herself, and she becomes only one cause among other causes. Finally, during the sixth stage, the child can mentally represent causal sequences and can recognize causes outside of her immediate perceptual field. Although Piaget's theory has been a prominent influence on developmental studies, scant research has been done regarding his ideas on the development of causal understanding in infancy. The little research that has been done has taken the form of attempts to devise scales in order to replicate Piaget's proposed sequence or to establish a relationship between development in causal understanding and some other developmental milestone. Uzgiris and Hunt (1975) devised a scale to assess * This study is based on a dissertation done under the direction of lna C. Uzgiris and submitted to the Department of Psychology at Clark University in partial fulfillment of the requirements for the Ph.D degree. Professor Uzgiris' invaluable support and guidance are gratefully acknowledged. I would also like to thank Robert Baker and Leonard Cirillo for their assistance with this project. Correspondence and requests for reprints should be sent to Miriam E. Sexton, Child Development Service, University of Massachusetts Medical School. Worcester, MA 0160.5.
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the way infants attempt to cause a reoccurrence of various physical events and concluded that there is a developmental progression in practical causal knowledge. Goulet (1974) constructed a causality scale that distinguished between behaviors regarding material causes and behaviors with respect to persons as causal agents. Using this scale he substantiated a developmental progression in causal understanding and also found that causality attributed to persons was either at a higher level or paralleled causality attributed to inanimate objects for all but two subjects in the sample. This suggests that a distinction between understanding of causal relations and of personal agency may be worth maintaining. A "frustration" situation was employed by Van Lieshout (1975) to study infants' use of other persons as causal agents but without independently assessing the infant's stage in causal development. The reactions of infants to the introduction of a barrier by their mothers between them and a toy were observed at 18 months and again at 24 months. It was found that infants either made independent efforts to reach the toy or attempted to obtain their mothers' help; moreover, the children directed less negative affect toward the toy or barrier and more positive overtures toward the mother at age 2 than at 18 months. He interpreted this result as reflecting significant changes in the child's ability to cognitively reconstruct the sequence of events involved in the barrier problem and to understand the mother's instrumental value. He argued that the older children were better able to understand that it was the mother who put the toy behind the barrier and that she would, therefore, know how to get it out. However, Van Lieshout's interpretation goes somewhat beyond the results of his study. The mother may have been used as an instrument by the 2-year-olds more frequently because of their greater experience with the mother's efficacy rather than because they better understood that she was the causal agent for setting up the barrier. The utilization of more than one agent is needed to ascertain whether the child has only a global understanding of another person as agent or whether she has the understanding of a specific person causing a particular event. In the present study, therefore, infants were shown events produced by the examiner, as well as by the mother, and, also, seemingly noncaused events. One of the goals of the present study was to trace the change in the infants' use of other persons as agents during the second year of life. Harding and Golinkoff (1979) attempted to relate infants' stage in causal development with their way of communicating a desire to the mother. The infants were exposed to two "frustration" episodes during which the mother caused events to occur that the infants could not replicate on their own. They found that only infants classified at Stage V of causal understanding used intentional vocalizations, that is, made eye contact with the mother by gesturing or looking while vocalizing. In the present study various behaviors of infants toward others as agents were examined. The expectation was that infants through the fourth stage of causal development would not treat other persons as agents because of their conviction of the necessity for self-activity in causing events to occur. In the fifth stage, when the infant begins to appreciate the autonomous causal powers of others, it was expected
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that the infants might attribute independent agency to only a few individuals, such as the mother, because of their greater concrete experience with the mother and their global understanding of causal connections. The child may appreciate the ability of others to act independently, but have little understanding of the actions of others as causes for specific events. With the beginning of representational thought during the sixth stage of development, it was expected that infants would better understand the cause and effect sequence of events and would be better able to conceptualize the involvement of a particular person in causing an event. Another goal of the present study was to examine the relationship between a child's understanding of the causes of physical events and her understanding of the agency of persons. For this purpose, several situations involving spectacles produced by inanimate objects were presented to the infants. The infants' stage of causal development with respect to inanimate objects was determined and related to their appreciation of the agency of others.
METHOD Subjects The subjects were 54 infants, equally distributed among the age groups of 11, 17, and 23 months. These ages were selected on the basis of previous research which suggested that these age groups might correspond to the fourth, fifth, and sixth stages of causal development. The sample consisted of equal numbers of boys and girls in each age group. Four additional infants were seen and then excluded from the sample due to lack of cooperation during the session.
Procedure The first portion of the experimental procedure consisted of six episodes in which various events, expected to be highly salient for infants, were alternately caused by the mother, by the examiner, or seemingly by neither person. Three of these events were regarded as "facilitative," in that the toy remained accessible to the child after the event occurred. The other three episodes were regarded as "prohibitive," in that the toy became inaccessible through the use of a barrier or obstacle after the crucial event. Both types of events were included to provide a broader array than in previous studies, which focused solely on "prohibitive" episodes. In each episode the child was able to examine the toy before the critical event centering on that toy occurred. The episodes were designed so that the infants would be unable to successfully cause the event to reoccur by themselves so as to enhance the likelihood of their turning to the two adults present. To further emphasize the agent's causative role, she produced the spectacle three times, at 1 minute intervals. The mothers were instructed not to comply with any requests by the infants to reactivate the toys. During the first episode, the mother activated a battery operated singing bird. In the second episode, a rubber ball was raised outside the infant's reach. This was accomplished by suspending the ball from the ceiling by a thread which was at-
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tached to a reel located behind the experimenter's back. This enabled her to surreptitiously raise the ball by winding the thread on the reel behind her back so that neither she nor the mother appeared to cause the ball to rise. During the third episode, the examiner activated a battery operated fire engine. In the fourth episode, the mother activated a battery operated drumming bear and then placed it in the center of a playpen so that the child could see, but not reach, the toy. During the fifth episode, a pecking chicken toy was activated so that the chicken's heads bobbed up and down. This was accomplished by pulling a string connected to the chicken's heads which extended from underneath the base. The string was pulled by the examiner, while seated at a distance from the toy, so that neither person was touching the toy when activated. In the sixth episode, the examiner placed a Slinky inside a transparent Plexiglas box so that the child could see but not reach the toy. In sum, this portion of the procedure consisted of two episodes in which the mother caused an event to occur, two episodes in which the examiner caused an event to occur, and two episodes in which neither person appeared to cause the event which occurred. One half of the sample was presented with the toys as described. The remaining one half of the sample was presented with the last three toys first and the first three toys last. This procedure permitted variation in the order of toy presentation while insuring that the same agent did not cause any two consecutive events. During the second portion of the experiment the infant's level of causal development was ascertained in situations concerned with the functioning of objects. Four items selected from the existing scales (Escalona & Corman, 1968; Goulet, 1974; Uzgiris & Hunt, 1975) pertinent to the fourth through sixth stages of causal development were presented. The Oscar the Grouch toy had a long cord to which the bulb was attached; when the bulb, which was hidden underneath the table, was squeezed, Oscar jumped up from his trash can. The Donald Duck toy had buttons located on either side of the base of the toy; when the buttons were pressed, Donald jumped over the ladder. The train had a large key on the side, which, when wound, moved the train. The bottle of soap bubbles and wand were used to demonstrate how to make soap bubbles. Children's responses to these items were used to assign them to a stage of causal understanding. Not all items tapped all stages; the items were selected so that three responses were scorable for the fourth, fifth, and sixth stages. An action performed on the moving parts of a toy, such as attempting to move the train by turning the wheels, was scored as a Stage IV response. Appropriate activation of a toy was scored as a Stage V response. Searching for the hidden cause of a spectacle was scored as a Stage VI response. The criterion for assignment to a specific stage was achievement of two out of the three possible responses at a particular level.
Scoring The examiner recorded the behavior of the 54 infants. For 14 children, an independent observer located behind a one-way mirror also recorded each infant's behavior
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to establish the reliability of the scoring. For the six experimental episodes interjudge reliability was 80%. For the four causal scale items interjudge reliability was 91% for the individual items, and 93% for stage placement. Stage placement for the child, about whom there was initial discrepancy, was decided by agreement between the judges. For the six experimental episodes the infant's behaviors were scored using the following categories: showing, offering, or pointing to the toy to obtain assistance, attempts to take the mother or the experimenter to the toy or barrier, verbal requests for assistance, and crying, emotional upset, or angry behavior directed at the mother or examiner. An overture was scored anytime one of these behaviors occurred and it was noted at whom it was directed. RESULTS
The Causality Items Examination of the data revealed a distribution of infants among the fourth through sixth stages of causal development in accord with the sequence suggested by Piaget. All I 1-month-old infants gave predominantly Stage IV responses. Of the 17-monthold subjects, 3 were classified at Stage IV, 12 at Stage V, and 3 at Stage VI. Among the 23-month-old subjects, 4 gave predominantly Stage V responses and 14 gave predominantly Stage VI responses.
Use of Agents Use of agents was assessed by the frequency of overtures to the two adults present. Preliminary analyses revealed no significant differences in frequency of overtures on the basis of sex, the order of episode presentation, or facilitative versus prohibitive episodes. Nonparametric statistics were selected for the analyses because the scores for the sample did not correspond to a normal distribution due to the large number of zero scores in the frequency of overtures for the 11-month-old group. A JonckheereTerpstra Test (Hollander & Wolfe, 1973) for the three groups showed that the frequency of overtures to other persons increased with age (z = 6.71, p < .001) and causal stage (z = 6.52, p < .001). The median frequencies of turns for the groups are presented in Table 1. Wilcoxon Matched-Pairs Signed-Ranks Tests were performed for the two oldest groups to assess whether they turned differentially to other persons. When the frequency of overtures to the mother was analyzed using the combined number of overtures to her on the two mother-caused episodes and on the two examiner-caused episodes as matched pairs, it was found that the 23-month-olds turned to the mother significantly less on the examiner-caused episodes (T = 15, p = < .01), whereas the 17-month-old group's rate of turning for assistance did not significantly differ for the two types of episodes. The magnitude of the difference between the two groups, as measured by a Mann-Whitney U Test, was also significant (U = 89.5, p < .025).
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TABLE 1 Median Frequencies of Overtures By Age and Causal Stage
Group Age 11 months 17 months 23 months Causal Stage
Median Frequency of Overtures 0.00 18.00 49.50
Stage IV
0.00
Stage V Stage VI
26.00 48.00
The frequency of overtures during the mother-caused and the seemingly noncaused episodes was also examined. When the rates of overtures on the mothercaused and the non-caused episodes were analyzed using Wilcoxon Tests, it was found that both the 23-month-olds (T = 5, p < .01) and the 17-month-olds (T = 17, p < .01) turned differentially on the basis of whether the event was caused or noncaused, with both groups turning for assistance to the mother significantly less on the non-caused episodes. The magnitude of the difference in the frequency of overtures in these two types of episodes was also significant when the two groups' scores were analyzed using a Mann-Whitney U Test (U = 93, p < .025), with the 23-month-old group turning differentially to the mother on the basis of whether an event was mother-caused or non-caused to a greater extent than the 17-month-old group. When the frequency of overtures to the examiner on the examiner-caused and the mother-caused episodes was analyzed, it was found that both the 23-month-olds (T = 0, p < .01) and the 17-month-olds (T = 3.5, p < .01) turned to the examiner significantly more on the examiner-caused episodes. The difference between the two groups in this respect was also significant (U -- 67.5, p < .01), with the 23month-old group turning differentially to the examiner on the basis of whether an event was examiner-caused or mother-caused to a greater extent. The frequency of overtures to the examiner for the examiner-caused and the apparently non-caused events was also analyzed. Wilcoxon Tests showed that both the 23-month-olds (T = 7, p < .01) and the 17-month-olds (T = 4.5, p < .01) turned to the examiner significantly less on the non-caused episodes. The difference in the magnitude of frequency between the two groups was also significant (U = 84.5, p < .01), with the 23-month-old group turning differentially to the examiner on the basis of whether an event was examiner-caused or non-caused to a greater extent. The median frequencies of overtures to the mother and to the examiner for the mother-caused, examiner-caused, and non-caused episodes are summarized in Table 2.
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TABLE 2 Median Frequencies of Overtures to the Mother and to the Examiner
Ep~ode Group
Mother-caused Episodes
Examiner-caused Episodes
Non-caused Episodes
Overtures to the Mother 17-month-old 23-month-old
8.95 19.89
4.67 8.39
3.34 6.28
Overtures to the Examiner 17-month-old 23-month-old
.78 1.45
3.17 16.39
.56 2.78
Use of Agents by Causal Stage Reanalysis of the data by causal stage rather than age revealed that the Stage IV group, similarly to the 11-month-old group, seldom turned to either of the adults for assistance during any of the episodes. However, the Stage V and Stage VI groups' frequencies of overtures were more similar to each other than when the data were analyzed by age. Both the Stage V and Stage VI infants turned to the mother more frequently on the mother-caused episodes and less frequently on the non-caused episodes, with the difference between the two groups not significant in this respect. Both groups also turned to the examiner more frequently on the examiner-caused episodes and less frequently on the non-caused episodes. The difference between the two groups on the examiner-caused episodes was significant (U = 83.5, p < .05), with the Stage VI subjects turning differentially to the examiner on the basis of her agency in causing an event to a greater extent than the Stage V subjects, whereas the difference between the two stage groups on the non-caused events was not significant. DISCUSSION The results of this study confirmed many of the initial expectations. As predicted, the frequency of overtures to others to get them to act for the infant increased dramatically with age and stage of causal development. Infants among the l lmonth-old group seldom turned to others to induce them to act. They attempted to solve the problem themselves by manipulating, shaking, or banging the toys or barriers. When this was unsuccessful in producing the desired effect, they quickly gave up and became interested in some other object in the room. The behavior of these infants was very similar to that described by Harding and Golinkoff (1979), whose Stage IV infants seldom directed vocalizations toward the mother and who
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banged a toy during a frustration episode rather than handing it to their mothers as a means of obtaining help. As predicted, the 23-month-olds turned to the mother significantly more often on the mother-caused than on the examiner-caused episodes, whereas the 17-montholds turned predominantly to the mother after both types of events• The oldest group also turned differentially to the examiner on the basis of whether an event was examiner-caused or mother-caused to a significantly greater extent than the intermediate group. Thus, the oldest group appeared to have a better understanding of the examiner's agency, as it more clearly discriminated between these two types of episodes. Differing frequencies of overtures on the person-caused and seemingly noncaused episodes were also found. The 23-month-olds turned differentially to the mother and to the examiner on the basis of whether an event was person-caused or non-caused to a significantly greater extent than the 17-month-olds. Thus, the oldest group better understood when a person had caused a particular event to occur and turned less frequently to implore the mother or the examiner to act on the apparently non-caused episodes. One interesting observation was that many of the 23-month-old subjects, after once ascertaining that a problem was too difficult, refused to manipulate the toy or barrier any further and instead directed their efforts exclusively at attempting to induce the adults present to recreate the desired event. An adult's refusal to comply with the infant's requests produced increasingly vigorous and persistent overtures from many of the infants and sometimes culminated in angry outbursts, during which they cried and threw themselves on the floor. This finding was similar to that obtained by Van Lieshout (1975), who noted that the frequency of crying and expressions of anger increased with age and that infants showing frequent upset at the mother showed relatively little positive behavior toward the toy. The behavior of the oldest infants also suggests a limitation of the understanding of causal relations during the sensorimotor period. While the sixth stage marks the beginning of representational thought, the behavior of the oldest children suggests that their achievements were not yet completely dissociated from the concrete situations in which the events occurred. Thus, these infants did not appear to fully possess an abstract conceptual notion of the interchangeability of persons as agents, that is, that an event need not be reproduced by the person who initially caused it. This was reflected in their persistence in turning predominantly to the specific agent responsible for an event, despite that person's refusal to comply, rather than using both persons interchangeably. For the mother-caused episodes, only 8% of the children's overtures were directed to the examiner. For the examiner-caused episodes, the percentage was somewhat higher, with 39% of the children's overtures directed toward the mother. Taken together, these data suggest that the children at this stage continued to remain at least partially tied to the concrete cause and effect sequences involved and, therefore, directed their overtures primarily to the specific agent responsible for the event.
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The differing frequencies of overtures for the intermediate and oldest groups were not clearly identified when the data were reanalyzed by causal stage rather than age. Both groups acted more in accord with the expectations for the sixth stage. The exception was in the frequency of turns to the examiner; the Stage VI group turned to the examiner significantly more often than the Stage V group on the examiner-caused, than on the mother-caused, episodes. The results of the reanalysis of the data may perhaps be explained by examining the method employed to ascertain level of causal development. The stage of causal understanding was determined with respect to objects, and the 17-month-olds were predominantly at the fifth stage. It is possible that many of the infants in the 17-month-old group were already at the sixth stage of causal development in relation to persons while still scoring at the fifth stage in relation to objects. Piaget (1954) suggested that causality attributed to persons would precede that attributed to objects. Some support for this contention was provided by Goulet (1974), who found that person-related causality either preceded or paralleled that of object-related causality for all but two infants in his sample. The oldest age group studied by Goulet was 13 months. In his study all subjects among this age group were at the sixth stage of causal development in relation to persons, whereas only slightly more than half of the group were at the sixth stage in relation to objects. Thus, the results for the intermediate group may have been due to the age group selected, and the predicted behavior might have been more clearly observed if a younger age group had been chosen. These findings also suggest that person-related and object-related causality may follow parallel but somewhat different courses, with person-related causality more pertinent in assessing understanding of agency. Similar distinctions between person- and object-related achievements have been made with respect to other Piagetian concepts, such as object permanence (Bell, 1970). Two recent causality studies also support a similar conclusion. Carlson-Luden (1980) found that 10month-old infants demonstrated differential rates of pushing a knob which produced either a human or nonhuman event as a consequence. Similarly, Golinkoff and Harding (1980) found that infants at 16 months of age made distinctions between animates and inanimates, as measured by their behavioral and emotional responses to an incongruous event produced by an inanimate object moving unaided. Taken together, these studies suggest that a distinction should be made between personrelated and object-related causality, and that the examination of the developmental course of these two concepts is a promising area for future research. REFERENCES
Bell, S. M. The development of the concept of object as related to infant-motherattachment. Child Development, 1970,41, 292-311. Carlson-Luden, V. Infant causality: Is it the same for social and nonsocial events? In R. Golinkoff (Chair), Causality- The development of causality. Symposiumpresented at the International Conference on Infant Studies, Hartford, April 1980.
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Escalona, S. K., & Corman, H. H. Albert Einstein scales of sensori-motor development: Causality scale. Unpublished manuscript, Albert Einstein.College of Medicine, 1968. Goldberg, S., & Lewis, M. Play behavior in the year-old infant: Early sex differences. Child Development, 1969, 40, 21-31. Golinkoff, R. M., & Harding, C. G. The development of causality: The distinction between animates and inanimates. In R. Golinkoff (Chair), Causality: The development of causality. Symposium presented at the International Conference on Infant Studies, Hartford, April 1980. Goulet, J. Conception of causality and reactions to strangers. In T. Decarie (Ed.), The infant's reaction to strangers. New York: International Universities Press, 1974. Harding, C. G-, & Golinkoff, R. M. The origins of intentional vocalizations in prelinguistic infants. Child Development, 1979, 50, 33-40. Hollander, M., & Wolfe, D. A. Nonparametric statistical methods. New Yo, John Wiley and Sons, 1973. Piaget, J. The construction of reali~, in the child. New York: Basic Books, 1954. Uzgiris, I. C., & Hunt, J. McV. Assessment in infants: Ordinal scales of psychological development. Urbana, IL: University of Illinois Press, 1975. Van Lieshout, C. F. Young children's reactions to barriers placed by their mothers. Child Development, 1975, "16. 879-886.
18 May 1981; Revised 1 February 1982 •