A comparison of imitation strategies in observational learning of action patterns

The effects of different arrangements of demonstration and imitation of modeled actions on the learning of the 26 handshapes of the American manual alphabet were investigated. A concurrent group (N =16), which imitated handshapes concurrently with their demonstration, was compared with a delayed group (N = 16), which delayed imitation until 3 handshapes had been displayed, and with a combination group (N = 16), which practiced under a combination of concurrent conditions early in acquisition and delayed conditions later in acquisition. Following acquisition, learning was assessed by means of immediate and long-term recall and recognition tests. The delayed group was superior to the concurrent group in long-term serial recall and in immediate and long-term recognition of 3-letter sequences (in nonserial order); the performance of the combination group was between those of the delayed and concurrent groups. Therefore, delaying imitation in acquisition required subjects to expend more cognitive effort to retain and produce handshapes when requested than did concurrent imitation. This was beneficial to development of task knowledge that could be relied on for postacquisition recall and recognition of handshapes.     

Effects of joint attention on long-term memory in 9-month-old infants: an event-related potentials study

Joint attention develops during the first year of life but little is known about its effects on long-term memory. We investigated whether joint attention modulates long-term memory in 9-month-old infants. Infants were familiarized with visually presented objects in either of two conditions that differed in the degree of joint attention (high versus low). EEG indicators in response to old and novel objects were probed directly after the familiarization phase (immediate recognition), and following a 1-week delay (delayed recognition). In immediate recognition, the amplitude of positive slow-wave activity was modulated by joint attention. In the delayed recognition, the amplitude of the Pb component differentiated between high and low joint attention. In addition, the positive slow-wave amplitude during immediate and delayed recognition correlated with the frequency of infants' looks to the experimenter during familiarization. Under both high- and low-joint-attention conditions, the processing of unfamiliar objects was associated with an enhanced Nc component. Our results show that the degree of joint attention modulates EEG during immediate and delayed recognition. We conclude that joint attention affects long-term memory processing in 9-month-old infants by enhancing the relevance of attended items.     

The memory is in the details: Relations between memory for the specific features of events and long-term recall during infancy

The second year of life is marked by pronounced changes in the length of time over which events are remembered. We tested whether the age-related differences are related to differences in memory for the specific features of events. In our study, 16- and 20-month-olds were tested for immediate and long-term recall of individual actions and temporal order of actions of three-step sequences in an elicited imitation paradigm as well as for forced-choice recognition of the specific feature of the props used to produce the sequences. Memory for the props was related to long-term recall of the events only for the 20-month-olds. It accounted for unique variance above and beyond the variance explained by immediate recall of the individual actions and the temporal order of actions of the sequences. The different pattern of relations in the older and younger infants seemingly reflects a developmental difference in the determinants of long-term recall over the second year of life.     

Influence of marihuana on storage and retrieval processe in memory

Following presentation and immediate free recall testing of 10 20-word lists, 48 Ss were divided into two groups, one of which received an oral dose of marihuana extract calibrated to 20 mg of Δ¹-THC and one of which received placebo. One hour later, all Ss were administered delayed recall, recognition, and order tests on the first set of words. Presentation of another set of 10 lists followed, and there were immediate recall and delayed recall, recognition, and order tests on these words. Performance of drug and placebo Ss did not differ significantly for any of the first delayed tests. However, the performance of drug Ss was poorer than that of placebo Ss on immediate recall, delayed recall, and delayed recognition of the second set of lists. We concluded that retrieval of information relevant to the occurrence or nonocurrence of an event was not affected by marihuana intoxication. Storage difficulties probably account for memory deficits due to the drug, and these difficulties appear to occur in the process of transferring information from short-term to long-term memory.     

Developments in long-term explicit memory late in the first year of life: behavioral and electrophysiological indices

Coincident with developments in the temporal-cortical explicit memory network, long-term recall abilities are newly emergent late in the first year of human life. We recorded event-related potentials (ERPs) in 9-month-olds as an index of the integrity of the neural substrate underlying a task thought to reflect explicit memory, namely, deferred imitation. ERP measures of recognition memory 1 week after unique laboratory experiences predicted whether and how much infants recalled of the experiences 1 month later. The findings further imply that memory storage and consolidation processes are a major source of variability in long-term recall memory late in the first year of life.     

Adult language use and infant comprehension of English: Associations with encoding and generalization across cues at 20 months

Adult-provided language shapes event memory in children who are preverbal and in those who are able to discuss the past using language. The research conducted to date, however, has not yet established whether infant language comprehension abilities moderate the extent to which preverbal infants benefit from adult-provided supportive language. The present study was conducted to address this question by examining immediate imitation and 1-week delayed generalization across cues in 20-month-old infants as a function of (a) variability in adult-provided linguistic support at encoding and test, (b) infant language comprehension abilities, and (c) their interaction. The provision of supportive adult language at encoding and test was associated with delayed generalization across cues although supportive adult language at encoding did not influence performance at immediate imitation. Infant language comprehension abilities were associated with performance at immediate imitation and delayed generalization across cues. In addition, infant language comprehension abilities moderated the extent to which infants benefited from adult-provided supportive language at encoding and test. The findings contribute to the literature by demonstrating that adult language use and infant language comprehension are independently and differentially associated with immediate imitation and 1-week delayed generalization across cues but also serve to jointly structure event memory in the second year of life.     

Forgetting curves in long-term memory: evidence for a multistage model of retention.

An experimental study with 20 normal healthy young adult subjects was performed to evaluate the interaction of type of memory tasks, type of learning modalities, and length of acquisition/recall interval. Four different tasks were employed (serial learning, paired learning, rote learning, and visuolinguistic transfer), some requiring a single trial learning modality others a multitrial learning modality. Acquisition/recall intervals were immediate, intermediate (3 min), and delayed. The experimental design allowed for the comparison of effects from five different delayed recall intervals (2, 8, 12, 24, and 48 hr). Results demonstrated a specific interaction on learning rates due to different ceiling effects for the different types of memory tasks. Forgetting rates, on the other hand, demonstrated a specific effect due to type of memory tasks and learning modalities only for differences between immediate and intermediate recall. These differences remained stable during the longer intervals and were not affected by length of interval. A multistage composition of long-term retention was suggested to explain these results, and a practical indication to build experimental procedures to study memory in the clinical field was evidenced.     

中英文对偶词呈现的空间位置对词义记忆的影响

采用即时记忆和延迟记忆任务,考察了双语信息加工对偶词呈现的空间位置对词义记忆的影响,结果表明：（1）对偶词呈现的空间位置对词义记忆存在影响,且这种影响只出现在延迟记忆中;（2）在延迟记忆任务中,变换词对呈现的空间位置,对对偶词记忆的效果要显著地优于固定空间位置条件;（3）对偶词的呈现背景不同对词对记忆没有影响。     

Reexposure breeds recall: effects of experience on 9-month-olds' ordered recall

On the basis of three experiences, 9-month-olds recall specific events after one month. We tested whether multiple experiences are necessary, or merely facilitative, of 9-month-olds' long-term recall. In two experiments, using deferred imitation, infants were exposed to multi-step sequences either one time, two times, or three times prior to a one-month delay. In Experiment 1, regardless of the number of experiences, infants did not demonstrate recall. In Experiment 2, infants were tested on and reexposed to the events after one week; recall was tested again one month later. Performance after 1 week in Experiment 2 was greater than performance after one month in Experiment 1. Moreover, presumably as a function of reexposure after one week, infants recalled the individual actions of the events one month later. Infants in the three-experience condition also evidenced ordered recall after one month. Implications for the developmental status of the neural substrate supporting long-term recall are discussed.     

Estimating the Capacity of Phonological Short-term Memory

Two methods of assessing the capacity of phonological short-term memory that minimize support from long-term memory were compared in a sample of 7- and 8-year-old children. The children were tested on immediate serial recall of words and nonwords, and on the serial recognition of sequences composed of words and nonwords. Serial recognition scores were found to be highly related to children's accuracy of recall of nonwords composed of low-probability phonotactic combinations, but were independent of the long-term memory contributions to recall estimated in the serial recall experiment. Children with high vocabulary knowledge performed significantly better than low vocabulary children on both the recall and recognition measures. It is argued that the convergence of the two techniques lends substantial validity to their use as assessments of phonological storage capacity relatively free of long-term memory influence, and that the crucial difference between children varying in vocabulary knowledge lies in this storage capacity rather than the differential availability and use of long-term knowledge.     

Evidence that nonconscious processes are sufficient to produce false memories

Are nonconscious processes sufficient to cause false memories of a nonstudied event? To investigate this issue, we controlled and measured conscious processing in the DRM task, in which studying associates (e.g., bed, rest, awake...) causes false memories of nonstudied associates (e.g., sleep). During the study phase, subjects studied visually masked associates at extremely rapid rates, followed by immediate recall. After this initial phase, nonstudied test words were rapidly presented for perceptual identification, followed by recognition memory judgments. On the perceptual identification task, we found significant priming of nonstudied associates, relative to control words. We also found significant false recognition of these nonstudied associates, even when subjects did not recall this word at study or identify it at test, indicating that nonconscious processes can cause false recognition. These recognition effects were found immediately after studying each list of associates, but not on a delayed test that occurred after the presentation of several intervening lists. Nonconscious processes are sufficient to cause this memory illusion on immediate tests, but may be insufficient for more vivid and lasting false memories.     

Developmental differences in schema dependency for temporally ordered story events

This research project was undertaken to investigate whether temporally ordered story events would be recalled in logical sequence as opposed to presentation order by various ages and under various task conditions. A 24-hour delayed condition was used as well as immediate recall. Six-year-olds, 8-year-olds, and adults were asked to recall four narratives. Instructions given were either vague or specifically required subjects to recall events exactly as they had been presented. Following the delayed recall, a picture-sequencing task was adminstered to assess whether picture cues would enable subjects to demonstrate awareness of input order even though they had reordered events in recall. All subjects reordered more during the delayed recall than during the immediate recall. Age differences (p<0003) occurred in the ability of subjects to demonstrate verbatim memory on the picture-sequencing task. Findings suggest that in contrast to adults, once children have reordered narrative events in memory, they no longer have an alternative verbatim version available. Results also suggest a greater schema dependency in children than in adults in recall tasks.     

Recency effects in delayed recall of mouthed stimuli

Auditory presentation leads to greater recency effects in recall than does visual presentation. This phenomenon (the modality effect) is found in both free and serial recall and in both immediate and delayed recall. Silent mouthing of visually presented stimuli also leads to enhanced recency effects in immediate serial recall. Two experiments reported here extend the generality of the mouthing effect by demonstrating that enhanced recency effects of mouthed stimuli occur in delayed serial and free recall. These results are inconsistent with theories that attribute the modality effect to a purely auditory sensory memory.     

Revisiting the rise and fall of false recall: Presentation rate effects depend on retention interval

Leading theories of false memory predict that veridical and false recall of lists of semantically associated words can be dissociated by varying the presentation speed during study. Specifically, as presentation rate increases from milliseconds to seconds, veridical recall is predicted to increase monotonically while false recall is predicted to show a rapid rise and then a slow decrease-a pattern shown by McDermott and Watson (2001) in a study using immediate recall tests. In three experiments we tested the generality of the effects of rapid presentation rates on veridical and false memory. In Experiments 1 and 2 participants exhibited high levels of false recall on a delayed recall test, even for very fast stimulus onset asynchronies (SOA)-contrary to predictions from leading theories of false memory. When we switched to an immediate recall test in Experiment 3 we replicated the pattern predicted by the theories and observed by McDermott and Watson. Follow-up analyses further showed that the relative output position of false recalls is not affected by presentation rate, contrary to predictions from fuzzy trace theory. Implications for theories of false memory, including activation monitoring theory and fuzzy trace theory, are discussed.     

The dawning of a past: the emergence of long-term explicit memory in infancy.

The ability to recall information about the past is thought to emerge in the 2nd half of the 1st year of life. Although there is evidence from both cognitive neuroscience and behavioral psychology to support this hypothesis, there is little longitudinal evidence with which the question can be addressed. Infants' memory abilities were tested between the ages of 9 and 16 months using elicited and deferred imitation. Infants' memory for events was tested after delays ranging from 1 to 6 months. The results suggest that at 9 months of age, infants are able to store and retrieve representations over delays of as many as 4 weeks but not over long delays. In contrast, 10-month-olds have at their disposal a system that allows encoding and retrieval of event representations over delays of up to 6 months. These results support the idea that the system that underlies long-term ordered recall emerges near the end of the 1st year of life.     

Revisiting the rise and fall of false recall: Presentation rate effects depend on retention interval

Leading theories of false memory predict that veridical and false recall of lists of semantically associated words can be dissociated by varying the presentation speed during study. Specifically, as presentation rate increases from milliseconds to seconds, veridical recall is predicted to increase monotonically while false recall is predicted to show a rapid rise and then a slow decrease—a pattern shown by McDermott and Watson (2001) in a study using immediate recall tests. In three experiments we tested the generality of the effects of rapid presentation rates on veridical and false memory. In Experiments 1 and 2 participants exhibited high levels of false recall on a delayed recall test, even for very fast stimulus onset asynchronies (SOA)—contrary to predictions from leading theories of false memory. When we switched to an immediate recall test in Experiment 3 we replicated the pattern predicted by the theories and observed by McDermott and Watson. Follow-up analyses further showed that the relative output position of false recalls is not affected by presentation rate, contrary to predictions from fuzzy trace theory. Implications for theories of false memory, including activation monitoring theory and fuzzy trace theory, are discussed.     

Does Controlling for Temporal Parameters Change the Levels-of-Processing Effect in Working Memory?

The distinguishability between working memory (WM) and long-term memory has been a frequent and long-lasting source of debate in the literature. One recent method of identifying the relationship between the two systems has been to consider the influence of long-term memory effects, such as the levels-of-processing (LoP) effect, in WM. However, the few studies that have examined the LoP effect in WM have shown divergent results. This study examined the LoP effect in WM by considering a theoretically meaningful methodological aspect of the LoP span task. Specifically, we fixed the presentation duration of the processing component a priori because such fixed complex span tasks have shown differences when compared to unfixed tasks in terms of recall from WM as well as the latent structure of WM. After establishing a fixed presentation rate from a pilot study, the LoP span task presented memoranda in red or blue font that were immediately followed by two processing words that matched the memoranda in terms of font color or semantic relatedness. On presentation of the processing words, participants made deep or shallow processing decisions for each of the memoranda before a cue to recall them from WM. Participants also completed delayed recall of the memoranda. Results indicated that LoP affected delayed recall, but not immediate recall from WM. These results suggest that fixing temporal parameters of the LoP span task does not moderate the null LoP effect in WM, and further indicate that WM and long-term episodic memory are dissociable on the basis of LoP effects.     

Effects of generation on immediate memory span and delayed unexpected free recall

We investigated the effects of generating words from fragments on pronunciation time, on immediate memory span, and on delayed free recall. Subjects read long words and short words aloud or generated them from strings with missing letters. Word-length and generation condition had multiplicative effects on speaking rate, as expected if each affected a separate process regulating the rate. We replicated the standard finding that span is smaller for longer words. Generation improved delayed free recall, indicating that relatively brief presentation times are adequate to produce a generation effect. Although generation improved long-term memory for the words, memory span was shorter for the words that were generated. The harmful effect of generation on span appears to be due to its slowing of speaking rate.     

Brief,pre-retrieval stress differentially influences long-term memory depending on sex and corticosteroid response

Previous work has indicated that stress generally impairs memory retrieval. However, little research has addressed discrepancies that exist in this line of work and the factors that could explain why stress can exert differential effects on retrieval processes. Therefore, we examined the influence of brief, pre-retrieval stress that was administered immediately before testing on long-term memory in males and females. Participants learned a list of 42 words varying in emotional valence and arousal. Following the learning phase, participants were given an immediate free recall test. Twenty-four hours later, participants submerged their non-dominant hand in a bath of ice cold (Stress) or warm (No Stress) water for 3 min. Immediately following this manipulation, participants’ memory for the word list was assessed via free recall and recognition tests. We observed no group differences on short-term memory. However, male participants who showed a robust cortisol response to the stress exhibited enhanced long-term recognition memory, while male participants who demonstrated a blunted cortisol response to the stress exhibited impaired long-term recall and recognition memory. These findings suggest that the effects of brief, pre-retrieval stress on long-term memory are sex-specific and mediated by corticosteroid mechanisms.     

Children's recall and recognition of sex role stereotyped and discrepant information

This research investigated the influence of differing levels of sex role stereotyped and discrepant information on immediate and delayed (one week) memory. Specifically, kindergarten and second-grade children's recall and recognition of stereotyped, moderately discrepant, and highly discrepant pictures were compared. In Study 1, a sorting procedure was utilized to determine the level of stereotyping of 34 toys. From this study 12 toys were selected as stimuli for Study 2. In Study 2, children's immediate and delayed recall and recognition was assessed. Results suggested significantly better recall of highly discrepant pictures than stereotyped or moderately discrepant pictures. In addition, immediate recall was better than delayed recall and second-grade recall was better than kindergarten recall. Similar trends emerged with the recognition task. Results were discussed with respect to the schematic processing model.This paper represents a joint collaborative effort on the part of the authors. The authors wish to thank the principals, teachers, and children who participated in the study; the child models; the student research assistants; the photographer, Martha Putt; and the statistical consultant, Joseph Kropp.