Age differences in the temporal locus of memory organization in children's recall

JOURNAL

OF EXPERIMENTAL

CHILD

33, 347-362 (1982)

PSYCHOLOGY

Age Differences in the Temporal Locus of Memory Organization in Children’s Recall DAVID F. BJORKLUND Florida

AND HOWARD S. HOCK

Atlantic

University

Age differences in when (i.e., at input or output) children organize information for recall were investigated in terms of a model specifying that information organized at input is more resistant to forgetting over time than information not organized at input. In Experiment 1, recall of items from categorically related and unrelated lists was assessed either immediately or after a 4-min delay. For 9-year-olds, the effect of delay was comparable for the related and unrelated lists, indicative of spontaneous organization at time of output. In contrast, 13year-olds showed a significantly smaller delay effect with related than with unrelated lists, indicative of spontaneous organization at time of input. Experiments 2 and 3 demonstrated that, for 9-year-olds, high levels of clustering in and of themselves do not eliminate effects of delayed testing characteristic of output organization, and that when 9-year-olds are biased to organize information at input, delay effects are reduced only when measures are taken to ensure that all the category labels are retrieved.

Age-related improvements in memory have typically been attributed to developmental differences in children’s tendencies to implement mnemonic strategies (see Kail & Hagen, 1977; Ornstein, 1978). Much of the developmental research has focused on age differences in the use of organizational techniques (Lange, 1978; Ornstein & Corsale, 1980; Moely, 1977), specifically on the spontaneity of children’s use of categorical information to facilitate recall. It has been shown that children under 12 years of age demonstrate little spontaneous organization in recall, although their performance can be significantly enhanced under Portions of this research were supported by a grant from the Spencer Foundation to David F. Bjorklund. Responsibility for all aspects of this research is equally shared by the two authors. We would like to thank the principals, teachers, and children of Henderson University School, Addison Mizner Elementary School, Bayview Elementary School, Jefferson Davis Middle School, and Our Lady Queen of Martyrs for their cooperation in helping us conduct this study. We would also like to thank Michael Tiburzi, Cathy Chance, Mary Thompson, and Barbara Zeman for their assistance in conducting the experiments, and Janet Hibel for her extensive pilot testing and helpful comments. Requests for reprints should be sent to David F. Bjorklund or Howard S. Hock, Department of Psychology, Florida Atlantic University, Boca Raton, FL 33431. 347 0022-0965/82/020347-16$02.00/O Copyright 8 1982 by Academic Press, Inc. All rights of reproduction in any form reserved.

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certain task and instructional conditions (e.g., Lange & Hultsch, 1970; Moely, Olson, Halwes, & Flavell, 1969). It has been argued that young children’s memory deficits can, in part, be attributed to their failure to organize information at time of item presentation, i.e., at input (e.g., Bjorklund, Ornstein, & Haig, 1977; Lange & Griffith, 1977; Moely et al., 1969). However, despite this deficit, some strategic processing may still occur for these young children. The present study investigated the possibility that young children, although failing to implement organizational strategies at time of item presentation, do engage in organizational techniques, but at time of item retrieval. More specifically, the present experiments were concerned with possible age differences in the temporal locus of organization in free recall. If category relations are noticed at time of item presentation (i.e., at input), the items in the list could be grouped according to their category identity, increasing the likelihood that category labels will be useful retrieval aids at time of output. Noticing .category relations during retrieval (i.e., at output) could also result in improved recall if children recall some items and (e.g., “dog” and “cow”), notice that they are categorically-related, use their prior knowledge of other words in their lexicon coded as “animals” to aid retrieval (e.g., “Let me think of some other animals. A horse is an animal. Was horse on the list?“). Evidence obtained by Bjorklund (1980a) suggests that when children under 12 years of age notice categorical relations, they tend to do so at time of output. Bjorklund presented 5, 8-, and 12-year-old children with sets of categorically related pictures for free recall, but prior to recall subjects were asked if they had noticed any groups of pictures that were alike or went together in some way. Five-year-olds and, to a somewhat lesser extent, &year-old children, reported significantly fewer categories than did the 12-year-olds. This suggests that the ability to notice category relations in a list of to-be-remembered items at time of input is not well established until the age of 12 years or so. Moreover, when the children were asked, after free recall, if they had noticed any additional groups of pictures that went together in any way, the 8-year-olds (but not the 5- or 12-year-olds) identified many of the categories they had previously omitted. This suggested that the 8-year-olds had discovered these categorical relations in the process of retrieving individual items. In a second study, Bjorklund (1980b) measured the latencies with which 8- and 12year-old children identified category relations in sets of to-be-remembered items. For the 12-year-olds, latencies to identify categories were comparable between subjects given standard free recall instructions (mean latency = 1.9 set) and those who had been encouraged to attend to category relations at time of item presentation (mean latency = 1.7 set). In contrast, the latencies of 8-year-olds in the standard free recall condition (mean latency = 10.8 set) were significantly longer than those

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of &year-old subjects who had been encouraged to use a categorical strategy at input (mean latency = 2.0 set). The results indicated that the lZyear-old subjects in the standard free recall condition had noticed category relations at time of input, whereas the &year-old children did not begin to search for category relations among the to-be-remembered items until they were instructed, prior to retrieval, to do so. These experiments, therefore, provide evidence of developmental differences in when (i.e., at input or output) children notice category relations among items in a list. However, they do not provide information concerning how (or whether) the category relations serve to facilitate recall. In fact, it is not certain from these experiments whether or not children would have identified category relations in the lists if they had not been asked by the experimenters to do so. The purpose of the present study is to determine if a similar age difference in the temporal locus of organization in memory can be found in the actual recall of list items where subjects are not asked to search for category relations. The experiments reported in this study were modified versions of a paradigm initially developed by Posner and Keele (1970) to study concept formation. The rationale for their paradigm was Bartlett’s (1932) assertion that schematic information is more resistant to forgetting over time than the detailed information from which the scheme is derived. The major question addressed in their study concerned whether adult subjects come to identify concept prototypes during the initial learning of individual concept members (i.e., at input) or whether such prototype abstraction arises only during later testing (i.e., at output). Posner and Keele reasoned that if the prototype were formed during the initial acquisition of the concept, classification accuracy for the prototypical or central pattern representing the concept would be less affected by a delay between acquisition and testing than classification accuracy for the particular exemplar patterns from which the prototype was derived, If, however, the prototype were not developed until the subjects began retrieving exemplars from memory, classification accuracy for the prototype would show the same detrimental effects of delayed testing as classification accuracy for the exemplars. Their results indicated that prototypes were formed from the exemplar patterns during learning, with a l-week delay impairing subjects’ identification of the exemplars more than their identification of the prototypes. When adapted for free recall, the logic of the Posner and Keele paradigm is retained. If, on the one hand, categorical relations are noticed at time of input, the items could be grouped or linked according to their category identity, making the items less susceptible to the effects of delayed testing than items from “unrelated” lists that have no categorical relations among the items (organization effects being less likely for the latter lists). If, on the other hand, category relations are not noticed until

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time of retrieval, subjects could still use their semantic knowledge of the categories as a retrieval aid, but recall of items from the categorically related lists should show the same detrimental effects of delayed testing as recall of items from unrelated lists. That is, if it is only during retrieval that children notice category relations, they could search for items according to their category identity, but the utility of this strategy should decrease with delayed testing as the likelihood of retrieving individual items decreases (the effect of delay on the retrieval of individual items being indicated by recall performance for the unrelated lists). In the first experiment, 9- and 13-year-old children were presented with sets of categorically related or unrelated words, and asked to recall these items immediately or after a filled delay period. It was predicted that category relations would be noticed and result in items being grouped according to their category identities at input for the older children. Thus, differences in recall between immediate and delayed testing were expected to be smaller for 13-year-olds receiving the categorically related items than for 13-year-olds receiving unrelated items. In contrast, it was predicted that 9-year-olds would nol group items according to category identity at input, but rather any categorical organization that these children show would occur at output. Thus, it was expected that their memory loss as a result of delay would be comparable for both the related and unrelated items. EXPERIMENT 1 Method Subjects One hundred and twelve children, 56 from grades 3 and 4 (33 boys and 23 girls; mean age: 9 years 0 months, range: 8 years 0 months to 10 years 6 months) and 56 from grade 8 (28 boys and 28 girls; mean age: 13 years 10 months, range: 12 years 8 months to 14 years 6 months) served as subjects. The subjects were students from three public schools in Palm Beach County, Florida. They were from predominantly middleto upper-middle-class homes. Children at each age level were randomly assigned to one of two experimental conditions, balancing as closely as possible for age, sex, and school. Design The children were given two separate lists of 20 items for oral recall. One group of subjects from each age group received two categorically related lists, and another group received two lists of unrelated items. Subjects were given a single free-recall trial ‘on one list immediately following its presentation (immediate recall). For the second list, a single free-recall trial was given 4 min after item presentation (delayed recall). The order in which the immediate- and delayed-recall tasks were pre-

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ORGANIZATION

sented was counterbalanced. Thus, the experimental design of this study was a 2 (Age: 9- vs 13-year-olds) x 2 (List Type: related vs unrelated) x 2 (Time of Testing: immediate recall vs delayed recall) x 2 (Order of Task Presentation: immediate-delayed vs delayed-immediate) factorial design, with repeated measures across the Time-of-Testing variable. Materials The four sets of items used in this experiment are presented in Table 1. Two of the 20-word lists consisted of categorically related items (four categories with five items per category); the remaining two lists were composed of words that could not be readily organized into categories or themes. The four lists were matched in terms of average Thorndike-Lorge (1944) word frequencies. As indicated above, the two ielated lists were presented to half of the subjects and the two unrelated lists were presented to the other half. Each list was presented equally often in the first and second positions of the testing order, and each was used equally often in the immediate and delayed-recall tests. Two different random presentation orders were generated for each related and unrelated list, with each order being used with equal frequency. STIMULUS

TABLE LISTS USED

I IN EXPERIMENTS

Related lists 1

Unrelated lists 2

Arm Ear Finger Foot Neck

Coat Dress Pants Shirt Shoes

Drum Fhrte Guitar Horn Piano

Desk Bed Bench Chair Couch

Barn Cabin Church House School

Comet Moon Planet Star Sun

Bear Dog Lion Pig Rabbit

Car Plane Ship Train Truck

Army Baby Block City Dime Door Egg Heart Lamp Leaf Nail News Page Pencil Radio Rain Ring Rock Salt Seed

Book Circus Clock Doll Father Fence Hammer Key Map Music Night Paper Pipe Shell Sign Soap Stairs Summer Tree Wheel

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Procedure

Subjects were tested individually in a single session, They were told that they would be presented with two lists of 20 words to remember, and were then given a six-item practice list with immediate free recall to familiarize them with the procedure. This was followed by practice trials on the Matching Familiar Figures (MFF) test (Kagan, 1965), with subjects being told that they would be asked to solve additional problems on this visual match-to-sample task sometime later in the session. The MFF was used as an interpolated activity between item presentation and recall in the delayed-recall task in order to minimize rehearsal during the delay interval. Subjects were not told that recall would be tested immediately for one list and under delayed conditions for the other. Similarly, subjects receiving the related lists were not informed of the categorical nature of the materials. Once it was clear, following the practice list, that subjects understood the task, the first list of test items was presented. The experimenter read the items at a rate of one word every 4 set, with the child repeating each word. In the immediate-recall condition, following the presentation of the last item, subjects were asked to name all of the words that they could remember in any order desired. In the delayed-recall condition, subjects were presented with the MFF test immediately after item presentation, and told to do a few of the MFF problems prior to recalling the words. After 4 min, the experimenter asked the child to recall as many of the words as he/she could. Pilot testing had indicated that a 4min interval was sufficient to produce delay effects with the unrelated lists for both age groups of children, but not so long as to result in floor effects for the 9-year-olds. In both testing conditions, once a child said that he/she could not recall any more words, or after a IO-set period in which no word was recalled, the experimenter asked the child to think of all the items that were presented. If a subject did not recall another word within the next 15-set interval, the recall trial was ended, and subjects were given the second recall task (delayed recall if immediate recall had been tested first, and vice versa). Instructions were repeated, and subjects were not told that the second task would be different in any way from the first. Results and Disucssion Recall

Subjects’ mean levels of recall are presented in Table 2. The analysis of the recall data produced significant main effects of Age, F(1, 104) = 118.79, p < .OOl, List Type, F(1, 104) = 43.11, p < .OOl, and Time of Testing, F(1, 104) = 23.98, p < .OOl. The effect of Order of Task Presentation and all interactions involving Order were not statistically

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TABLE 2 EXPERIMENT

1: MEAN RECALL AND CLUSTERING (ARC) SCORES BY AGE, LIST TYPE, AND TIME OF TESTING (CLUSTERING SCORES PRESENTED IN PARENTHESES)

List type Related

Unrelated

9-year-olds Immediate (I) Delay (D) I-D

1.07 (.23) 4.14 (.25) 2.93 (- .02)

5.11 3.61 1.50

13-year-olds Immediate (I) Delay (D) I-D

11.57 (.59) 11.25 (.52) 0.32 (.07)

8.46 6.25 2.21

significant. The only other effects to reach significance were the Age x List Type interaction, F(1, 104) = 23.98, p < .OOl, and the Age x

List Type x Time of Testing interaction, F(1, 104) = 5.45, p < .05. The presence of this significant three-way interaction is consistent with the hypothesis that delayed testing would have differential effects on the related and unrelated materials as a function of age. For the older subjects, it was predicted that any decrement of performance on the related lists as a result of delay would be significantly less than that found for the unrelated lists. Such a pattern would be interpreted as reflecting categorical organization at time of input. In contrast, it was hypothesized for the younger children that effects of categorical relatedness between items would occur at output. It was predicted, therefore, that memory loss due to delayed testing for these children would be comparable for the related and unrelated lists. The hypothesized effects of delayed testing were assessed by computing a difference score (immediate recall minus delayed recall) for each subject. The difference between the “difference scores” (i.e., delay effects) for the related and unrelated lists was not significant for the 9-year-olds, t(54) = 1.74, p > .05, and furthermore, was in the opposite direction to that predicted for input organization. However, the difference of the differences between the related and unrelated conditions for the 13-year-olds was significant, t(54) = 2.28, p < .05. Clustering

Clustering measures were computed for both immediate and delayed recall for subjects receiving the related lists (see Table 2). The Alternative Ratio of Clustering (ARC) measure (Roenker, Thompson, & Brown, 1971) was used as an index of clustering. Perfect clustering is set at an

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ARC score of 1.0, chance clustering is set at zero, and negative values represent clustering less than expected by chance. Although the absolute levels of clustering were low for the 9-year-olds, clustering was significantly greater than chance values for both the immediate, t(27) = 2.04, p = .05, and delayed, t(27) = 2.75, p < .Ol, testing conditions. This finding confirmed the presence of an organizational effect for these young children. Clustering levels were higher and clearly above chance values for the 13-year-olds (immediate recall, t(27) = 8.76, p < .OOl; delayed recall, t(27) = 5.55, p < .Ol). The clustering data were further analyzed in an Age (2) x Time of Testing (2) x Order of Task Presentation (2) analysis of variance. The analysis yielded only a significant effect of Age, F(1, 52) = 10.07, p < .OOl, with 13-year-olds demonstrating significantly higher clustering than 9-year-olds. Although the 9-year-old children in this experiment did show greater than chance clustering, the absolute level of clustering in their recall was low. Thus, it is possible that the pattern of recall data obtained for these younger subjects could be attributed to those children who did not organize information (either at input or at output), and may not reflect organization at output, per se. That is, an alternative explanation to our output-organization hypothesis, is that delay effects are found only for children who fail to organize items, and that if organization occurs at all, it is found at input. This possibility was investigated in the present data. Based on the 9-year-olds’ mean clustering scores (average of immediate and delayed recall), recall performance was compared for the 14 children having the highest clustering scores (M = .57, SD = .20) and the 14 having the lowest clustering scores (M = - .08, SD = .27). The effect of delay on recall of items from the categorically related lists (as measured by the mean immediate recall minus delayed recall difference scores) was not significantly different between the high (mean difference = 3.14 words) and low (mean difference = 2.7 1 words) clustering groups, r(26) < 1. That is, significant delay effects are found for 9-yearolds even when levels of clustering are high, indicating that this organization was initiated at time of item retrieval. EXPERIMENT

2

The results of the first experiment provided evidence for developmental differences in the temporal locus of organization in free recall, with 13year-old children grouping items according to their category identities at time of input and 9-year-olds organizing items at time of output. Although significant effects of category relatedness on recall (related vs unrelated lists) were found for children of both ages, the levels of clustering in the related lists were relatively low for the 9-year-olds. A cuedrecall procedure was therefore introduced in this experiment to ensure high levels of clustering without affecting any strategies subjects may

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(or may not) use at time of item presentation. If 9-year-old children continue to demonstrate effects of delayed testing in cued recall, it would indicate that high levels of output organization, in and of themselves, are not sufficient to eliminate delay effects. A second purpose of this experiment was to assess the effects of giving 9-year-old children category information at time of input as well as output. Will they continue to show significant effects of delayed testing, or will they demonstrate the minimal delay effects characteristic of category grouping at time of input (as spontaneously shown by 13-year-old children)? Method Subjects

One hundred and fourteen fourth-grade children (mean age: 9 years 6 months, range: 8 years 9 months to 10 years 7 months), 56 boys and 58 girls, served as subjects. Children were selected from one public school and one private school in South Florida. They were from predominantly middle- to upper-middle-class homes. The children were randomly assigned to one of three experimental groups, balanced as closely as possible by age, sex, and school. Design,

Materials,

and Procedure

Each child was presented with two 20-item lists of categorically related words that were identical to the related word lists used in Experiment 1. Subjects received one list in an immediate-recall test and one in a delayed-recall test. The order in which the immediate and delayed testing conditions and lists were presented was counterbalanced across subjects in each condition. Subjects were assigned to one of three cuing conditions. (1) Oufput Cue: Subjects in this condition were given standard free-recall instructions with list items presented in random order. However, at time of recall, they were provided with the category labels, one at a time, and were asked to recall all members from that category (e.g., “Tell me all the ANIMALS that were on the list.“). The order in which the four list categories were cued was counterbalanced over subjects. Following the request for items from the last category, subjects were asked if there were any additional words that they could remember. (2) Input/Output Cue: Children in this condition were presented the items blocked by categories and told that they could enhance their recall by trying to remember the words by category. The experimenter identified each category when the first word of that category was presented (e.g., “These next words are all FURNITURE.“). The order in which the categories were presented at input was counterbalanced across subjects. At recall, subjects were given the category labels in counterbalanced orders, as were subjects in the Output-Cue condition, with the additional

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stipulation that the last list category presented at input not be the first list category cued at recall. (3) No Cue: Subjects in this condition were presented items in random order and given standard free-recall instructions identical to those given to subjects in Experiment 1. Performance in this condition served as a baseline for assessing the effect of delay on recall performance. Results Mean recall and clustering scores are presented in Table 3. An analysis of variance of the recall data produced significant main effects of Time EXPERIMENT CONDITION

TABLE 3 2: MEAN RECALL AND CLUSTERING (ARC) SCORES OF ~-YEAR-OLDS BY CUING AND TIME-OF-TESTING (CLUSTERING SCORESPRESENTED IN PARENTHESES) Cuing condition

Input/output Immediate (I) Delay (D) I-D

No cue

Output cue

cue

6.05 (.20) 3.74 (.09) 2.31 1.11)

9.32 (.95) 7.26 (.87) 2.06 t.08)

12.42 (.97) 12.05 (.%) 0.37 (.Ol)

of Testing, F(1, 108) = 25.65, p < .OOl, and Cuing Condition, F(2, 108) = 130.72, p < .OOl. Subsequent Newman-Keuls tests (p < .05) demonstrated that subjects in the Input/Output-Cue condition recalled significantly more words than subjects in the Output-Cue condition, who, in turn, recalled significantly more words than subjects in the No-Cue condition. The effect of Order of Task Presentation (immediate-delayed vs delayed-immediate) and all interactions involving Order were not statistically significant. Also significant was the Cuing Condition x Time of Testing interaction, F(2, 108) = 3.83, p < .05. Tests of simple effects indicated that the effect of delay was significant for the No-Cue, Ffl, 108) = 36.79, p < .OOl, and Output-Cue, F(1, 108) = 28.90, p < .OOl, conditions, but not significant for the Input/Output-Cue condition, F(1, 108) < 1.’ The analysis of the clustering (ARC) scores produced only a significant effect of Cuing Condition, F(2, 108) = 94.08, p < .OOl, with subjects ’ A similar result was obtained when the data were analyzed by computing “difference scores” (immediate recall minus delayed recall) for each subject, and entering these values into a one-way analysis of variance. The differences among the three cuing conditions were significant, F(2, 111) = 3.78, p < .OS. Newman-Keuls tests (p < .OS) demonstrated that mean difference scores of subjects in the No-Cue and Output-Cue conditions were not statistically different from each other, but both were significantly greater than the scores for subjects in the Input/Output-Cue condition.

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in the Input/Output-Cue and Output-Cue conditions demonstrating significantly (p < .Ol) greater clustering than subjects in the No-Cue condition. Clustering for subjects in the No-Cue condition was significantly greater than chance for immediate recall t(37) = 2.17, p < .05, but not for delayed recall, t(37) < 1. As in the first experiment, delay effects (immediate recall minus delayed recall) were compared between those children in the No-Cue condition having the overall highest ARC scores (N = 19, M = .54, SD = .20) with those having the overall lowest ARC scores (N = 19, M = - .25, SD = .33). Similar to the results of Experiment 1, delay effects were comparable between the high (mean difference = 2.00 words) and low (mean difference = 2.63 words) clustering groups, t(36) < 1, indicating that what organization these children demonstrated in recall occurred at time of output. Discussion The results of this experiment show that significant effects of delayed testing are obtained when levels of recall and clustering are high (the Output-Cue condition) as well as when levels of recall and clustering are low (the No-Cue condition). In both conditions, 9-year-olds demonstrate effects of delayed testing characteristic of organizational effects occurring at time of output. That these children are capable of grouping items according to category identity at time of input, but fail to demonstrate it spontaneously, is shown by the results of the Input/Output cuing condition. In this condition 9-year-olds show the small effects of delayed testing characteristic of the input organization strategy that is spontaneously used by 13-year-olds. EXPERIMENT

3

The findings of Experiment 2 demonstrated that providing category labels as retrieval cues alone is not sufficient to reduce delay effects in recall. However, when 9-year-olds are biased to organize information at input and given the category labels as retrieval cues, minimal effects of delayed testing are found. Although providing 9-years-olds with category cues both at input and output produced a pattern of recall characteristic of input-organization, we do not know how the provision of categorical input cues, without the benefit of retrieval cues, would affect delayed recall. Previous research (e.g., Bjorklund et al., 1977; Ringel & Springer, 1980) indicates, for immediate recall, that performance for 9-year-olds given input cues only should be enhanced relative to performance in a No-Cue condition. What remains to be determined is whether organizational cues provided at input alone are sufficient to produce minimal effects of delayed testing characteristic of the spontaneous performance of older children.

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Method Subjects

Fifty-six fourth-grade children (mean age: 9 years 3 months; range: 8 years 7 months to 10 years 4 months), 24 boys and 32 girls, served as subjects. Children were selected from a nonremedial, university-sponsored summer program in South Florida, and were from predominantly middle- to upper-middle-class homes. The children were randomly assigned to one of two conditions, balanced as closely as possible by age and sex. Design, Materials,

and Procedure

Children received the same two 20-item lists of categorically related words used in Experiments 1 and 2, one for immediate testing and one for delayed testing. The order in which the immediate and delayed-testing conditions and lists were presented was counterbalanced across subjects in each condition. Children in the Input-Cue condition received items blocked by categories and were told that they could enhance their recall by thinking of the items in terms of their category membership. These “input” instructions were identical to those received by subjects in the Input/Output-Cue condition in Experiment 2. Subjects were instructed to recall the items in any order they wished (i.e., free recall), and were not given category cues at time of retrieval. Subjects in the No-Cue condition received the same random presentations and free recall instructions as in the corresponding condition of Experiment 2. Results Mean recall is presented in Table 4. As can be seen, recall for subjects given input cues was significantly greater than for subjects in the NoCue condition, F(1, 52) = 18.05, p < .Ol. However, subjects in both the Input-Cue and No-Cue conditions showed a significant decrement in recall as a result of delayed testing, F(1, 52) = 15.09, p < .Ol. The Cuing Condition x Time of Testing interaction was not significant, F(1,

EXPERIMENT CONDITION

TABLE 4 3: MEAN RECALL AND CLUSTERING (ARC) SCORES OF 9-YEAR-OLDS

Immediate (1) Delay (D) I-D

AND TIME-OF-TESTING

(CLUSTERING

BY CUING SCORES PRESENTED IN PARENTHESES)

No cue

Input cue

7.29 (.29) 5.86 (53) 1.43 (-.24)

10.47 (.92) 7.50 (.87) 2.97 (.05)

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52) = 1.84, p < .05, nor were any other effects in the analysis. Although input cuing improved recall for both immediate and delayed testing, subjects given input cues still demonstrated a significant memory loss as a result of delayed testing that was actually somewhat larger than that shown by subjects in the No-Cue condition. The delay effect found for children in the Input-Cue condition was apparently due to these subjects’ forgetting list categories over the 4-min interpolated interval. Many subjects in the Input-Cue condition commented during delayed recall that they knew there were more groups of words, but that they could not remember what the categories were. Subjects often knew how many categories they had forgotten, but, being unable to retrieve the category label, they were not able to recall individual category exemplars. This loss of category information is reflected in the mean number of categories from which subjects recalled at least one item. Children in the Input-Cue condition recalled words from significantly more categories in immediate recall (M = 3.18) than in delayed recall (M = 2.39), t(27) = 3.60, p < .Ol. In contrast, the mean number of words they recalled for each category represented in their protocols (words per category) was comparable between immediate (M = 3.31) and delayed recall (M = 3.08), t(27) = 1.27, p > .05. Inspection of the clustering scores indicated uniformly high levels of clustering for subjects in the Input-Cue condition (see Table 4). Twentytwo of 28 subjects (79%) in this condition had perfect (1 .OO) clustering in immediate recall, with 21 of 28 subjects (75%) demonstrating perfect clustering in delayed testing. The analysis of the clustering data yielded a significant main effect of Cuing Condition, F(1, 52) = 34.98, p < .OOl, and a significant Cuing Condition x Time of Testing interaction, F(1, 52) = 5.18, p < .05. Subsequent tests of simple effects demonstrated no significant differences in clustering between immediate and delayed testing in the Input-Cue condition, F(I, 52) < 1. However, clustering in delayed recall was significantly greater than that in immediate recall for subjects in the No-Cue condition, F(1, 52) = 14.66, p < .Ol. This unexpectedly high level of clustering shown by subjects in the No-Cue condition under delayed testing was still significantly less than that shown by subjects in the Input-Cue condition, F(1, 104) = 21.58, p < .OOl. As in the first two experiments, delay effects (immediate recall minus delayed recall) for subjects in the No-Cue condition were compared between children having the overall highest ARC scores (N = 14, M = .71, SD = .22) with those having the overall lowest ARC scores (N = 14, M = .lO, SD = .24). The results of this analysis replicated those of Experiments 1 and 2, with delay effects being comparable between the high (mean difference = 1.71 words) and low (mean difference = 1.14 words) clustering groups, r(26) < 1.

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Discussion The results of this experiment indicate that grouping items on the basis of category labels at input is not sufficient for 9-year-olds to demonstrate minimal effects of delayed testing. The 9-year-olds in the Input-Cue condition of this experiment demonstrated high levels of categorical clustering under both immediate and delayed testing, but had difficulty retaining, over a 4-min filled interval, the category labels by which the list items were organized. Failure to retrieve the category labels resulted in entire groups of items becoming inaccessable, reducing overall levels of performance. Thus, category labels for 9-year-olds seem to be subject to the same effects of delayed testing as individual list items. The category labels themselves constitute a short, unrelated list of items, and as indicated by the results of Experiment 1, substantial effects of delayed testing are obtained for unrelated lists. In fact, the 25% loss of category labels as a result of delay in this experiment is comparable to the loss observed for 9-year-olds given a list of 20 unrelated words in Experiment 1 (29% loss). This presents the possibility of a capacity difference between 9- and 13-year-old children in their ability to retain short lists of unrelated items or category labels over brief delay intervals. GENERAL DISCUSSION The intent of these experiments was to assess possible developmental differences in the temporal locus of organization in children’s free recall. It was hypothesized that list items organized at input are more resistant to forgetting over time than list items that are not organized at input. For the 13-year-old children in Experiment 1, categorical grouping at time of input was indicated by the relatively small memory decrement in delayed testing obtained for categorically related lists compared with the decrement obtained for lists with no categorical relations among the items. For 9-year-old children, however, the memory decrements in delayed testing were comparable for the categorically related and unrelated lists. This constituted evidence for organization occurring at time of output by showing that the likelihood of 9-year-olds noticing and using category relations during retrieval decreased with delay to about the same extent as did their likelihood of retrieving individual items (the latter being indicated by the effect of delay on the recall of items from the unrelated list). Furthermore, the amount of memory decrement as a result of delay was comparable between 9-year-olds who showed high levels of clustering and those whose clustering scores were not significantly different from chance. This finding was replicated for subjects in the No-Cue conditions in Experiments 2 and 3. These results provide evidence that many of the younger children actually were engaging in categorical organization, but at time of retrieval rather than at time of item presentation.

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The results of Experiment 2 provided additional evidence consistent with this interpretation, indicating that when 9-year-old subjects are provided with category cues at time of output only, recall is enhanced, but significant delay effects are still obtained. The results of Experiment 3 indicated that organization at input in and of itself is not sufficient to eliminate delay effects in recall. Nine-year-old children biased to organize at input demonstrated enhanced levels of recall and clustering, but nevertheless showed a significant reduction in recall as a result of delay. Further inspection of these subjects’ data indicated that the recall decrement was due to children forgetting some of the list categories over delay. There appears to be an expense to organizing list items by category labels at input, in that if category labels are “lost” subjects are unable to retrieve the individual items organized on the basis of the category term. Thus, in addition to differences in spontaneous grouping of items at time of input, differences in the ability to retain short lists of “unrelated” information over brief delay periods may also be responsible for performance differences between 9- and 13-year-old children tested in these experiments. Only when children group items by category labels at input and have access to the category labels over the delay interval, as the 9-year-olds in the Input/Output-Cue condition in Experiment 2 and the 13-year-olds in Experiment 1, are levels of recall high and comparable for immediate and delayed testing. In conclusion, the results of these experiments suggest age differences in the spontaneous processing of categorical information for recall and a dichotomy in operations occurring during the initial presentation of information (i.e., at input) and operations occurring during retrieval (i.e., at output). Although it is speculative, these data are consistent with the position that, whereas 13-year-olds likely enter the memory task with the intent to implement some organizational strategy, 9-year-olds may “discover” a strategy only as a result of retrieving individual items. That is, categorical relations may be discovered while a child is in the process of recalling individual items, with subsequent recall being organized according to these groupings. REFERENCES Bartlett, F. C. Remembering: A study in experimental rind social psychology. Cambridge: Cambridge Univ. Press, 1932. Bjorklund, D. F. Children’s identification of category relations in lists presented for recall. Journal of Genetic Psychology, 1980, 136, 45-53. (a) Bjorklund, D. F. Developmental differences in the timing of children’s awareness of category relations in free recall. International Journal ofBehavioral Development, 1980, 3, 61-70. (b) Bjorklund, D. F., Omstein, P. A., & Haig, J. R. Development of organization and recall: Training in the use of organizational techniques. Developmental Psychology, 1977, 13, 175-183.

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Kagan, J. Impulsive and reflective children: Significance of conceptual tempo. In J. D. Krumholtz (Ed.), Learning and the educational process. Chicago: Rand McNally, 1965. Kail, R. V., Jr., & Hagen, J. W. (Eds.), Perspectives on the development of memory and cognition. Hillsdale, N.J.: Erlbaum, 1977. Lange, G. Organization-related processes in children’s recall. In P. A. Ornstein (Ed.), Memory development in children. Hillsdale, N.J.: Erlbaum, 1978. Lange, G., & Griffith, S. B. The locus of organizational failures in children’s recall. Child Development,

1977, 48, 1498-1502.

Lange, G. W., & Huhsch, D. F. The development of free classification and free recall in children. Developmental Psychology, 1970, 3, 408. Moely, B. E. Organizational factors in the development of memory. In R. V. Kail, Jr., & J. W. Hagen (Eds.), Perspectives on the development of memory and cognition. Hi&dale, N.J.: Erlbaum, 1977. Moely, B. E., Olson, F. A., Halwes, T. G., & Flavell, J. H. Production deficiency in young children’s clustered recall. Developmental Psychology, 1969, 1, 26-34. Ornstein, P. A. (Ed.). Memory development in children. Hillsdale, N.J.: Erlbaum, 1978. Ornstein, P. A., & Corsale, K. Organizational factors in children’s memory. In C. R. Puff (Ed.). Organization, structure, and memory. New York: Academic Press, 1980. Posner, M. I., & Keele, S. W. Retention of abstract ideas. Journal of Experimental Psychology,

1970, 83, 304-308.

Ringel, B. A., & Springer, C. J. On knowing how well one is remembering: The persistence of strategy use during transfer. Journal of Experimental Child Psychology, 1980, 29, 322-333. Roenker, D. L., Thompson, C. P.. & Brown, S. C. Comparison of measures for the estimation of clustering in free recall. Psychological Bulletin, 1971, 75, 45-48. Thorndike, E. L., & Lorge, I. The teacher’s word book of 30,000 words. New York: Teachers College, Columbia University, Bureau of Publications, 1944. RECEIVED:

March 24, 1981;

REVISED:

July 9. 1981.