Constraints on retrieval search for episodic information in children and adults

The hypothesis that a lack of structural constraint limits children's ability to use context and category cues to search associative memory for episodic information is examined in this study. Second and fifth graders and college adults were shown word triplets at acquisition and asked to recall the final target member of each triplet in a cued recall task. The manipulations concerned sources of associative structure that could constrain retrieval search. The degree to which the members of the triplets were associated was varied, as well as the kind of association, and the kind and amount of retrieval support provided in the cue, and encoding was constrained by orienting questions or was unconstrained. The results showed that children's effective use of retrieval cues was more dependent on episodic associative structure, retrieval support, and the constrained encoding of associative information than was adults'. Differences in the associative structure of information in permanent memory seemed to contribute to the results.     

Item-specific and relational encoding effects in children's recall and recognition memory for words

This study tests the hypothesis that children's deficiency in encoding itemspecific and relational information in episodic events contributes to age differences in recall and recognition. In two experiments, grade school children and college adults were presented with word triplets varying in categorical relatedness. The processing of the item-specific and relational information in the triplets was independently manipulated. Experiment 1 assessed cued recall, and Experiment 2 assessed recognition of both the central target and incidental contextual members of each triplet. The results showed that the processing manipulations had independent and different effects on recall and recognition, on memory for the members of the different kinds of triplets, on the use of the retrieval cues, and on memory for target and incidental words. Developmental differences were found in both recall and recognition, and of both target and incidental words, that varied with triplet type and the processing manipulations and that were attributable to differences in the encoding of item-specific and relational information in the triplets. The discussion contrasts alternative accounts of children's encoding deficiency, and suggests that the distinction between automatic, age-invariant, and strategic age-sensitive encoding processes needs to be redrawn.     

Picture memory: How the action schema affects retention

When an action scene is viewed, an action schema guides the formation of an episodic representation. Within episodic memory, items of high relevance to the theme of the action schema are represented in a prototypical form closely connected to the action theme. In contrast, items of low relevance are represented in detail but their representation is unconnected to that of the action. The action schema is used as a retrieval framework for both recalling and recognizing whether or not an item was depicted in a scene (i.e., item presence), but is not used for recognition of figurative detail (i.e., item appearance). Four experiments confirmed these hypotheses. Children, aged 7- and 9-years, and adults organized pictured scenes around themes from action schemata. The appearance of high relevant items was recognized poorly, while their presence was recalled well. Memory for the presence of high relevant items surpassed that for low relevant items even when recognition of item names was assessed. Conversely, the appearance of low relevant items was recognized accurately, but memory for their presence was difficult to retrieve.     

Recognition versus recall of briefly presented visual information: a developmental study.

Five-year-olds, as compared to adults, have displayed a striking constraint on short-term recognition memory for briefly presented visual information. In the present study, a recall paradigm was also examined to test the generality of this constraint. Additionally, we examined the possibility that forced verbal report might differentially enhance children's performance. Evidence of improved performance in children would suggest that a verbal encoding strategy, used by adults only during the recognition task, is activated in children in a recall task. Though recall memory performance of young children did surpass recognition memory levels, the same was true for adults with the relative adult-child difference remaining constant across conditions. It was concluded that processes other than verbal labeling (e.g., buffer storage, organization, retrieval) are probably more responsible for age differences in immediate memory performance than labeling, per se.     

Integrated memory for objects, places, and temporal order: evidence for episodic-like memory in mice

Human episodic memory refers to the recollection of an unique past experience in terms of what happened, and where and when it happened. Factoring out the issue of conscious recollection, episodic memory, even at the behavioral level, has been difficult to demonstrate in non-human mammals. Although, it was previously shown that rodents can associate what and when or what and where information given on unique trials, it proved to be difficult to demonstrate memory for what, where, and when simultaneously in mammals, without using extensive training procedures, which might induce semantic rather than episodic memory recall. Towards the goal of an animal model of human episodic memory we designed an three-trial object exploration task in which different versions of the novelty-preference paradigm were combined to subsume (a) object recognition memory, (b) the memory for locations in which objects were explored, and (c) the temporal order memory for object presented at distinct time points. We found that mice spent more time exploring two "old familiar" objects relative to two "recent familiar" objects, reflecting memory for what and when and concomitantly directed more exploration at a spatially displaced "old familiar" object relative to a stationary "old familiar" object, reflecting memory for what and where. These results suggest that during a single test trial the mice were able to (a) recognize previously explored objects, (b) remember the location in which particular objects were previously encountered, and (c) to discriminate the relative recency in which different objects were presented. According to the currently discussed behavioral criteria for episodic-like memory in animals, our results suggest that mice are capable to form such higher order memories.     

Developmental differences in recall and recognition: The relationship between rehearsal and memory as test expectation changes

An overt rehearsal procedure was used to study the relationship between children's rehearsal strategies and their memory performance under different conditions of test expectation. Previous work has shown that developmental differences in rehearsal content affect recall performance. This study was designed to address the question of why active rehearsal content results in superior recall performance. The equivalence of recognition-memory performance for third- (age 9) and sixthgraders (age 12) suggests that developmental differences in recall are due to the effects of rehearsal content on item retrieval from permanent memory. In addition, the data indicate that third- and sixth-graders can differentiate between expected recall and recognition tests and, with the exception of the sixth-grade boys, use this information to modify their rehearsal content. These differences in rehearsal content, as a function of the type of test expected, corresponded to changes in recall performance.     

Episodic Indexing: A Model of Memory for Attention Events

People often remember what they attend to in the world. Such memory can be cast as a kind of mental catalog or index of attended objects. To investigate how such an index is acquired and used, protocol data were collected from a programmer who scrolled to off-screen objects from time to time as she worked. These protocol data were modeled using Soar, which constrains how the index is constructed. In the model, an index entry is an episodic trace encoded during attention. The trace associates the attention event with a time symbol denoting the event's occurrence. Later, the model can ask itself whether it saw that object by calling to mind an image of the attention event. If this image retrieves a time symbol, then the model infers that the object exists and can reason about bringing the object back into view. Episodic indexing is a theory of these encoding and retrieval processes. It posits that information about attention events is encoded automatically, but that retrieval requires effort and knowledge. Episodic indexing is congruent with a range of results on episodic and temporal codes and recognition and recall processes. It incorporates source monitoring (Johnson, Hashtroudi, & Lindsay, 1993) and is a simple and pervasive form of long-term working memory (Ericsson & Kintsch, 1995).     

Cued recall from image and sentence memory: a shift from episodic to identical elements representation

The applicability of the identical elements (IE) model of arithmetic fact retrieval (T. C. Rickard, A. F. Healy, & L. E. Bourne, 1994) to cued recall from episodic (image and sentence) memory was explored in 3 transfer experiments. In agreement with results from arithmetic, speedup following even minimal practice recalling a missing word from an episodically bound word triplet did not transfer positively to other cued recall items involving the same triplet. The shape of the learning curve further supported a shift from episode-based to IE-based recall, extending some models of skill learning to cued recall practice. In contrast with previous findings, these results indicate that a form of representation that is independent of the original episodic memory underlies cued-recall performance following minimal practice.     

Episodic encoding and recognition of pictures and words: role of the human medial temporal lobes

In the present PET study, we examined brain activity related to processing of pictures and printed words in episodic memory. Our goal was to determine how the perceptual format of objects (verbal versus pictorial) is reflected in the neural organization of episodic memory for common objects. We investigated this issue in relation to encoding and recognition with a particular focus on medial temporal-lobe (MTL) structures. At encoding, participants saw pictures of objects or their written names and were asked to make semantic judgments. At recognition, participants made yes-no recognition judgments in four different conditions. In two conditions, target items were pictures of objects; these objects had originally been encoded either in picture or in word format. In two other conditions, target items were words; they also denoted objects originally encoded either as pictures or as words. Our data show that right MTL structures are differentially involved in picture processing during encoding and recognition. A posterior MTL region showed higher activation in response to the presentation of pictures than of words across all conditions. During encoding, this region may be involved in setting up a representation of the perceptual information that comprises the picture. At recognition, it may play a role in guiding retrieval processes based on the perceptual input, i.e. the retrieval cue. Another more anterior right MTL region was found to be differentially involved in recognition of objects that had been encoded as pictures, irrespective of whether the retrieval cue provided was pictorial or verbal in nature; this region may be involved in accessing stored pictorial representations. Our results suggest that left MTL structures contribute to picture processing only during encoding. Some regions in the left MTL showed an involvement in semantic encoding that was picture specific; others showed a task-specific involvement across pictures and words. Together, our results provide evidence that the involvement of some but not all MTL regions in episodic encoding and recognition is format specific.     

Associative recognition processes are modulated by the semantic unitizability of memoranda

Although memory of episodic associations is generally considered to be recollective in nature, it has been suggested that when stimuli are experienced as a unit, familiarity processes might contribute to their subsequent associative recognition. To investigate the effect of semantic relatedness during episodic encoding on the processes of retrieval of associative information, we had participants interactively encode pairs of object pictures, vertically arranged so as to suggest a functional or configural relationship between them. Half the pairs were independently judged to be of related objects (e.g., a lamp over a table) and half of unrelated objects (e.g., a key-ring over an apple). At test, participants discriminated between intact, recombined, and new pairs while event related potentials (ERPs) were recorded. In an early ERP marker of retrieval success generally associated with familiarity processes, differences related to associative memory only emerged for related pairs, while differences associated with item memory emerged for both related and unrelated pairs. In contrast, in a later ERP effect associated with recollection, differences related to associative memory emerged for both related and unrelated pairs. These findings may indicate that retrieval of episodic associations formed between two semantically related visual stimuli can be supported by familiarity-related processes.     

Developmental differences in remembering sentences after integrative or selective semantic processing

Fifth graders (age: 10 years) and college undergraduates performed one of four different semantic orienting activities on a series of agent-action-object sentences. Afterwards all subjects received a memory test combining recognition for whole sentences with cued recall for component agents, actions, and objects. Overall levels of both recall and recognition varied with the orienting activities. Relative recallability of agents, actions, and objects varied with orienting activity as well. Recognition performance improved with grade level but recall did not. The interaction between type of memory test and grade level was taken to indicate that organization of material in memory increases during adolescence even when the total amount of material stored does not.     

Modeling memory and perception

I present a framework for modeling memory, retrieval, perception, and their interactions. Recent versions of the models were inspired by Bayesian induction: We chose models that make optimal decisions conditioned on a memory/perceptual system with inherently noisy storage and retrieval. The resultant models are, fortunately, largely consistent with my models dating back to the 1960s, and are therefore natural successors. My recent articles have presented simplified models in order to focus on particular applications. This article takes a larger perspective and places the individual models in a more global framework. I will discuss (1) the storage of episodic traces, the accumulation of these into knowledge (e.g., lexical/semantic traces in the case of words), and the changes in knowledge caused by learning; (2) the retrieval of information from episodic memory and from general knowledge; (3) decisions concerning storage, retrieval, and responding. Examples of applications include episodic recognition and cued and free recall, perceptual identification (naming, yes–no and forced‐choice), lexical decision, and long‐term and short‐term priming.     

Category specificity in normal episodic learning: applications to object recognition and category-specific agnosia

Studies of patients with category-specific agnosia (CSA) have given rise to multiple theories of object recognition, most of which assume the existence of a stable, abstract semantic memory system. We applied an episodic view of memory to questions raised by CSA in a series of studies examining normal observers' recall of newly learned attributes of familiar objects. Subjects first learned to associate arbitrarily assigned colors or textures to objects in a training phase, and then attempted to report the newly learned attribute of each object in a recall task. Our subjects' pattern of recall errors was similar both quantitatively and qualitatively to the identification deficits among patients with CSA for biological objects. Furthermore, errors tended to reflect conceptually and structurally based confusions. We suggest that object identification involves recruitment and integration of information across distributed episodic memories and that this process is susceptible to interference from objects that are structurally similar and conceptually related.     

Involuntary memory and the development of retrieval skills in young children

An incidental memory paradigm was used to study involuntary encoding processes and voluntary retrieval strategies in children's memory. Preschool (mean age: 4 years, 4 months) and kindergarten (mean age: 5 years, 10 months) children sorted pictures according to their color or category membership, and then received either a recall test (Experiment 1) or a recognition test (Experiment 2). Better retention of category- than color-sorted items was observed for kindergarten children in free recall, preschool and kindergarten children in cued recall, and neither group in recognition. These results were interpreted in terms of the retrieval strategies used by children in each of the memory tasks. The importance of distinguishing between voluntary and involuntary memory processes, and between acquisition and retrieval, in studies of depth-of-processing was emphasized. Developmental differences in performance appear to derive primarily from the role of voluntary search strategies in retrieval, rather than from age differences in involuntary encoding processes.     

Retrieval of Episodic Information From Memory: Comparisons Among 3- and 4-Year-Olds, 7- and 8-Year-Olds,and Adults

Young children's and adults' recall of episodic information was explored in 4 experiments. The task required participants to recall a target noun presented as the last item of a 4-noun string of related (either categorically or thematically) or unrelated words. Providing all 3 preceding nouns or a subset of them cued recall. Experiment 1 found that 7- and 8-year-old children's recall was better with pictures as opposed to text, and children showed performance equal to adults with thematically related pictorial stimuli. Using pictorial stimuli, Experiment 2 showed that the number of cues present at retrieval affected 7- and 8-year-olds' recall. Experiments 3 and 4 tested recall of episodic information in 3- and 4-year-olds using pictorial stimuli. The results suggested that young children also have access to episodic information in memory and the number of cues present at retrieval influenced recall. The findings are discussed in the context of children's memory for events.     

Episodic and semantic memory in bilingual and monolingual children

Although bilinguality has been reported to confer advantages upon children with respect to various cognitive abilities, much less is known about the relation between memory and bilinguality. In this study, 60 (30 girls and 30 boys) bilingual and 60 (30 girls and 30 boys) monolingual children in three age groups (mean ages 8.5, 10.5 and 12.5 years) were compared on episodic memory and semantic memory tasks. Episodic memory was assessed using subject-performed tasks (with real or imaginary objects) and verbal tasks, with retrieval by both free recall and cued recall. Semantic memory was assessed by word fluency tests. Positive effects of bilingualism were found on both episodic memory and semantic memory at all age levels. These findings suggest that bilingual children integrate and/or organize the information of two languages, and so bilingualism creates advantages in terms of cognitive abilities (including memory). Some sex differences were also found in episodic memory but not in semantic memory. This episodic memory difference was found with younger children.