The semantic-similarity effect in children: influence of long-term knowledge on verbal short-term memory

Verbal working memory encodes phonological and semantic information differently

Working memory (WM) is often tested through immediate serial recall of word lists. Performance in such tasks is negatively influenced by phonological similarity: People more often get the order of words wrong when they are phonologically similar to each other (e.g., cat, fat, mat). This phonological-similarity effect shows that phonology plays an important role for the representation of serial order in these tasks. By contrast, semantic similarity usually does not impact performance negatively. To resolve and understand this discrepancy, we tested the effects of phonological and semantic similarity for the retention of positional information in WM. Across six experiments (all Ns = 60 young adults), we manipulated between-item semantic and phonological similarity in tasks requiring participants to form and maintain new item-context bindings in WM. Participants were asked to retrieve items from their context, or the contexts from their item. For both retrieval directions, phonological similarity impaired WM for item-context bindings across all experiments. Semantic similarity did not. These results demonstrate that WM encodes phonological and semantic information differently. We propose a WM model accounting for semantic-similarity effects in WM, in which semantic knowledge supports WM through activated long-term memory.

Effects of semantic relationship and preactivation on memory updating

Semantic relationship modulates working memory (WM) processes by promoting recall but impairing recognition. Updating is a core mechanism of WM responsible for its stability and flexibility; it allows maintenance of relevant information while removing no-longer relevant one. To our knowledge, no studies specifically investigated how WM updating may benefit from the processing of semantically related material. In the current study, two experiments were run with this aim. In Experiment 1, we found an advantage for semantically related words (vs. unrelated) regardless of their association type (i.e., taxonomic or thematic). A second experiment was run boosting semantic association through preactivation. Findings replicated those of Experiment 1 suggesting that preactivation was effective and improved semantic superiority. In sum, we demonstrated that long-term semantic associations benefitted the updating process, or more generally, overall WM function. In addition, pre-activating semantic nodes of a given word appears likely a process supporting WM and updating; thus, this may be the mechanism favoring word process and memorization in a semantically related text.

Semantic memory and reading comprehension: the relationship through adulthood and aging

Literature shows a relationship between working memory and reading comprehension during lifespan and aging. In addition, a difference between genres of text was shown: the expository text affects the already limited cognitive resources of the older adults, whereas narrative text comprehension seems to be preserved. Undoubtedly, also semantic knowledge plays a key role in reading comprehension; though, and to our knowledge, there are no studies clearly showing the relation between semantic knowledge and reading comprehension in aging. In the current study, we administered to younger adults and older adults a semantic working memory task, two word-span tasks and two reading comprehension tests (narrative and expository genre) to investigate the role of semantic knowledge during comprehension. In line with previous findings, we found that younger adults used flexibly either taxonomic or thematic knowledge, whereas the older adults mainly used thematic knowledge (better preserved from age-related decline). Originally, we found that in younger adults, thematic knowledge accounted for narrative text comprehension, whereas backward span performance accounted for expository text comprehension. On the contrary, in older adults no specific predictors were found for narrative text comprehension, whereas both thematic knowledge and education level were significant predictors of expository text comprehension. Results were discussed in the light of the possible protective role of some factors such as education level and mostly, as an instance of cognitive reserve exemplified by use of thematic knowledge as a residual ability.

The Emergence of Richly Organized Semantic Knowledge from Simple Statistics: A Synthetic Review

As adults, we draw upon our ample knowledge about the world to support such vital cognitive feats as using language, reasoning, retrieving knowledge relevant to our current goals, planning for the future, adapting to unexpected events, and navigating through the environment. Our knowledge readily supports these feats because it is not merely a collection of stored facts, but rather functions as an organized, semantic network of concepts connected by meaningful relations. How do the relations that fundamentally organize semantic concepts emerge with development? Here, we cast a spotlight on a potentially powerful but often overlooked driver of semantic organization: Rich statistical regularities that are ubiquitous in both language and visual input. In this synthetic review, we show that a driving role for statistical regularities is convergently supported by evidence from diverse fields, including computational modeling, statistical learning, and semantic development. Finally, we identify a number of key avenues of future research into how statistical regularities may drive the development of semantic organization.

The Role of Co-Occurrence Statistics in Developing Semantic Knowledge

The organization of our knowledge about the world into an interconnected network of concepts linked by relations profoundly impacts many facets of cognition, including attention, memory retrieval, reasoning, and learning. It is therefore crucial to understand how organized semantic representations are acquired. The present experiment investigated the contributions of readily observable environmental statistical regularities to semantic organization in childhood. Specifically, we investigated whether co-occurrence regularities with which entities or their labels more reliably occur together than with others (a) contribute to relations between concepts independently and (b) contribute to relations between concepts belonging to the same taxonomic category. Using child-directed speech corpora to estimate reliable co-occurrences between labels for familiar items, we constructed triads consisting of a target, a related distractor, and an unrelated distractor in which targets and related distractors consistently co-occurred (e.g., sock-foot), belonged to the same taxonomic category (e.g., sock-coat), or both (e.g., sock-shoe). We used an implicit, eye-gaze measure of relations between concepts based on the degree to which children (N = 72, age 4-7 years) looked at related versus unrelated distractors when asked to look for a target. The results indicated that co-occurrence both independently contributes to relations between concepts and contributes to relations between concepts belonging to the same taxonomic category. These findings suggest that sensitivity to the regularity with which different entities co-occur in children's environments shapes the organization of semantic knowledge during development. Implications for theoretical accounts and empirical investigations of semantic organization are discussed.

Statistical regularities shape semantic organization throughout development

Our knowledge about the world is represented not merely as a collection of concepts, but as an organized lexico-semantic network in which concepts can be linked by relations, such as "taxonomic" relations between members of the same stable category (e.g., cat and sheep), or association between entities that occur together or in the same context (e.g., sock and foot). To date, accounts of the origins of semantic organization have largely overlooked how sensitivity to statistical regularities ubiquitous in the environment may play a powerful role in shaping semantic development. The goal of the present research was to investigate how associations in the form of statistical regularities with which labels for concepts co-occur in language (e.g., sock and foot) and taxonomic relatedness (e.g., sock and pajamas) shape semantic organization of 4-5-year-olds and adults. To examine these aspects of semantic organization across development, we conducted three experiments examining effects of co-occurrence and taxonomic relatedness on cued recall (Experiment 1), word-picture matching (Experiment 2), and looking dynamics in a Visual World paradigm (Experiment 3). Taken together, the results of the three experiments provide evidence that co-occurrence-based links between concepts manifest in semantic organization from early childhood onward, and are increasingly supplemented by taxonomic links. We discuss these findings in relation to theories of semantic development.

Episodic context reinstatement promotes memory retention in older but not younger elementary schoolchildren

Previous studies have shown that reinstatement of spatial and temporal background information during learning can promote memory retention in adults. However, the effect in children is unclear. In order to explore the effect of episodic context reinstatement on the memory retention of different age groups, first-grade students, third-grade students, and third-year college students studied two word lists. When the words were presented mixed together, the participants were told to either restudy the words under intentional learning conditions or make list discrimination judgements by indicating the list from which each word had originated. Results revealed that the retrieval practice based on the episodic context reinstatement paradigm showed a phased development trend in the participants compared to restudy. Episodic context reinstatement only promoted memory retention in the third-grade children and college students, but not in the first-grade children. During the early elementary school years, children do not have relatively mature episodic memory ability and cannot output memories according to context clues. Our finding suggests important guidance for the age-appropriate use of tests as instructional tools in basic education. Statement of contribution What is already known on this subject? One recent theory of retrieval-based learning is the episodic context account; it promotes memory retention by reinstate the context of a prior learning episode. Previous studies have confirmed in the adults that the episodic context reinstatement was the main reason for retrieval practice to promote memory retention through the list discrimination tasks What does this study add? This study revealed that the retrieval practice based on the episodic context reinstatement paradigm showed a phased development trend in the participants. Episodic context reinstatement only promoted memory retention in the third-grade children and college students, but not in the first-grade children, and the results support the episodic context assumption, namely that episodic context reinstatement is the key factor in memory retention. The results of this study can explain why most prior work has observed the effect of retrieval practice in the groups above grade three.

Sensitivity detection in memory recognition: interference control as index of taxonomic memory development?

We investigated how long-term memory modulates recognition accuracy performance in typically developing primary school children (aged 7 vs. 9 years). We devised a verbal working memory task where words associations were manipulated to obtain different types of semantic associations (i.e., taxonomic, thematic). Sensitivity detection measures were operationalised as difference between hits and false alarms (for both internal and external intrusions). As our main result, we found sensitivity detection for taxonomic associations was greater in older children than younger. In turn, this showed that taxonomies produce more interference in younger children, and thus, they are not able to take advantage from taxonomic associations, as older children do. These results are helpful in sketching a developmental trend of how semantic memory impacts recognition processes in memory.

[Formula: see text] Developmental dyslexia: How taxonomic and thematic organization affect working memory recall

Semantic long-term memory (LTM) representations can be distinguished in two main classes: taxonomic (i.e., abstract) and thematic (i.e., concrete, experiential). In typically developing children, taxonomies are usually acquired after thematic representations. In the current study, we investigated how LTM semantic representations modulate working memory (WM) recall in children with developmental dyslexia (DD). A sample of children with DD from primary and secondary school paired with a control group for age, gender, schooling, and IQ was administered a semantic WM (SWM) dual task. Here, children had to listen to groups of lists composed of words semantically related (taxonomic, e.g., shop- drugstore-coffee; or thematic, e.g., light-heat-fire) or arbitrarily related, and afterward to recall the last words among each group. Both taxonomic and thematic organizations supported recall in the two groups of children. More specifically, data showed that in typically developing children the taxonomic organization boosted WM recall (vs. the thematic one). On the contrary, in children with DD, the taxonomic organization did not better support recall and yielded effects similar to thematic organization. In children with DD, abstract taxonomic knowledge seems to be less frequently used than thematic knowledge. Findings contribute to sketch memory functioning across different memory systems in DD.

Long-term memory effects on working memory updating development

Long-term memory (LTM) associations appear as important to cognition as single memory contents. Previous studies on updating development have focused on cognitive processes and components, whereas our investigation examines how contents, associated with different LTM strength (strong or weak), might be differentially updated at different ages. To this end, we manipulated association strength of information given at encoding, in order to focus on updating pre-existing LTM associations; specifically, associations for letters. In particular, we controlled for letters usage frequency at the sub-lexical level. We used a task where we dissociated inhibition online (i.e., RTs for updating and controlling inhibition from the same set) and offline (i.e., RTs for controlling inhibition from previously updated sets). Mixed-effect analyses were conducted and showed a substantial behavioural cost when strong associations had to be dismantled online (i.e., longer RTs), compared to weak ones; here, in primary school age children. Interestingly, this effect was independent of age; in fact, children from 7–8 to 9–10 years were comparably sensitive to the strength of LTM associations in updating. However, older children were more effective in offline inhibitory control.

Phonological and Semantic Contributions to Verbal Short-Term Memory in Young Children With Developmental Stuttering

Purpose The purpose of this study was to examine the verbal short-term memory skills of children who stutter (CWS) and children who do not stutter (CWNS) in 2 experiments, focusing on the influence of phonological and semantic similarity. Method Participants were 42 CWS and 42 CWNS between the ages of 3;0 and 5;11 (years;months). In Experiment 1, children completed the phonological similarity task, in which they listened to lists of phonologically similar and dissimilar words and then repeated them when signaled to do so. In Experiment 2, children completed another forward span task, the semantic category task, which is similar to the phonological similarity task, except that it consisted of lists of semantically homogeneous and heterogeneous words. Main dependent variables were cumulative memory span, proportion of errors by type, and speech reaction time (SRT) for correct responses. Results The CWS exhibited significantly shorter memory spans for phonologically dissimilar words and were less affected by the phonological qualities of the words than the CWNS in Experiment 1, based on the findings of both between-groups and within-group analyses. In Experiment 2, although the groups did not differ in their performance in either condition, within-group analyses revealed that the CWNS benefitted from semantic similarity, whereas the CWS did not. The between-groups difference in absolute difference scores, however, did not reach significance. The CWS produced more omissions and false alarms than the CWNS in both experiments, but the 2 groups of children were otherwise comparable in SRT, although the CWS exhibited overall faster SRT than the CWNS in Experiment 2. Conclusions Verbal short-term memory is one domain-general cognitive process in which CWS display weakness relative to typically fluent peers. These weaknesses are likely due, in part, to differences in phonological and, perhaps, semantic processing of words to aid memory.

Developmental changes in semantic knowledge organization

Semantic knowledge is a crucial aspect of higher cognition. Theoretical accounts of semantic knowledge posit that relations between concepts provide organizational structure that converts information known about individual entities into an interconnected network in which concepts can be linked by many types of relations (e.g., taxonomic, thematic). The goal of the current research was to address several methodological shortcomings of prior studies on the development of semantic organization, by using a variant of the spatial arrangement method (SpAM) to collect graded judgments of relatedness for a set of entities that can be cross-classified into either taxonomic or thematic groups. In Experiment 1, we used the cross-classify SpAM (CC-SpAM) to obtain graded relatedness judgments and derive a representation of developmental changes in the organization of semantic knowledge. In Experiment 2, we validated the findings of Experiment 1 by using a more traditional pairwise similarity judgment paradigm. Across both experiments, we found that an early recognition of links between entities that are both taxonomically and thematically related preceded an increasing recognition of links based on a single type of relation. The utility of CC-SpAM for evaluating theoretical accounts of semantic development is discussed.