Relations between neural structures and children's self-derivation of new knowledge through memory integration

Differentiation of Related Events in Hippocampus Supports Memory Reinstatement in Development

Adults are capable of either differentiating or integrating similar events in memory based on which representations are optimal for a given situation. Yet how children represent related memories remains unknown. Here, children (7-10 years old) and adults formed memories for separate yet overlapping events. We then measured how successfully remembered events were represented and reinstated using fMRI. We found that children formed differentiated representations in the hippocampus-such that related events were stored as less similar to one another compared with unrelated events. Conversely, adults formed integrated representations, wherein related events were stored as more similar, including in medial prefrontal cortex. Furthermore, hippocampal differentiation among children and medial prefrontal cortex integration among adults tracked neocortical reinstatement of the specific features associated with the individual events. Together, these findings reveal that the same memory behaviors are supported by different underlying representations across development. Specifically, whereas differentiation underlies memory organization and retrieval in childhood, integration exhibits a protracted developmental trajectory.

Individual differences diminish the pretest effect under productive memory conditions

Pretesting, or asking a test question prior to the onset of learning, is a well-established means of enhancing learning. Research on pretesting has focused primarily on direct factual learning outcomes. Yet building a coherent knowledge base also depends on productive memory processes that permit going beyond the information directly given. In the specific productive process of self-derivation through memory integration, individual differences are prominent; verbal comprehension is a consistent predictor. In the current work, we integrated these research trends by testing the extent to which pretesting enhances learning through productive memory processes and the role played by individual differences in verbal comprehension. Across four within-subjects experiments, we assessed the pretest effect after accounting for variability associated with verbal comprehension. In Experiments 1-3, we assessed the productive memory process of self-derivation through memory integration. Adults were more successful on pretest trials compared to control (i.e., no pretest) trials, but this effect was no longer significant after controlling for verbal comprehension. This pattern emerged when we used stem-fact pretests (Experiment 1) and integration-fact pretests (Experiment 2) to probe self-derivation across single-sentence stimuli and replicated when we used stimuli more akin to everyday learning materials (i.e., text passages and photographs; Experiment 3). In Experiment 4, we shifted the test target from productive processes to fact recall and found the pretest effect held even after controlling for verbal comprehension. This research bridges the pretest and productive process literature to provide novel insight into ways of maximizing learning. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

Age differences in generalization, memory specificity, and their overnight fate in childhood

Memory enables generalization to new situations, and memory specificity that preserves individual episodes. This study investigated generalization, memory specificity, and their overnight fate in 141 4- to 8-year-olds (computerized memory game; 71 females, tested 2020-2021 in Germany). The results replicated age effects in generalization and memory specificity, and a contingency of generalization on object conceptual properties and interobject semantic proximity. Age effects were stronger in generalization than in memory specificity, and generalization was more closely linked to the explicit regularity knowledge in older than in younger children. After an overnight delay, older children retained more generalized and specific memories and showed greater gains but only in generalization. These findings reveal distinct age differences in generalization and memory specificity across childhood.

Distinct multivariate structural brain profiles are related to variations in short- and long-delay memory consolidation across children and young adults

From early to middle childhood, brain regions that underlie memory consolidation undergo profound maturational changes. However, there is little empirical investigation that directly relates age-related differences in brain structural measures to memory consolidation processes. The present study examined memory consolidation of intentionally studied object-location associations after one night of sleep (short delay) and after two weeks (long delay) in normally developing 5-to-7-year-old children (n = 50) and young adults (n = 39). Behavioural differences in memory retention rate were related to structural brain measures. Our results showed that children, in comparison to young adults, retained correctly learnt object-location associations less robustly over short and long delay. Moreover, using partial least squares correlation method, a unique multivariate profile comprised of specific neocortical (prefrontal, parietal, and occipital), cerebellar, and hippocampal head and subfield structures in the body was found to be associated with variation in short-delay memory retention. A different multivariate profile comprised of a reduced set of brain structures, mainly consisting of neocortical (prefrontal, parietal, and occipital), hippocampal head, and selective hippocampal subfield structures (CA1-2 and subiculum) was associated with variation in long-delay memory retention. Taken together, the results suggest that multivariate structural pattern of unique sets of brain regions are related to variations in short- and long-delay memory consolidation across children and young adults.

Determinants of elementary-school academic achievement: Component cognitive abilities and memory integration

Children are on a quest for knowledge. To achieve it, children must integrate separate but related episodes of learning. The theoretical model of memory integration posits that the process is supported by component cognitive abilities. In turn, memory integration predicts accumulation of a knowledge base. We tested this model in two studies (data collected in 2016-2018) with second (8-year-olds; n = 391; 196 female; 36% Black, 27% Hispanic/Latinx, 29% White, and 8% multiracial) and third (9-year-olds; n = 282; 148 female; 36% Black, 31% Hispanic/Latinx, 27% White, and 5% multiracial) graders. The results support the theoretical model and the role of verbal comprehension in learning new information, and also indicate that verbal comprehension alone is not sufficient to build knowledge.

A meta-analysis of the relation between hippocampal volume and memory ability in typically developing children and adolescents

Memory is supported by a network of brain regions, with the hippocampus serving a critical role in this cognitive process. Previous meta-analyses on the association between hippocampal structure and memory have largely focused on adults. Multiple studies have since suggested that hippocampal volume is related to memory performance in children and adolescents; however, the strength and direction of this relation varies across reports, and thus, remains unclear. To further understand this brain-behavior relation, we conducted a meta-analysis to investigate the association between hippocampal volume (assessed as total volume) and memory during typical development. Across 25 studies and 61 memory outcomes with 1357 participants, results showed a small, but significant, positive association between total hippocampal volume and memory performance. Estimates of the variability across studies in the relation between total volume and memory were not explained by differences in memory task type (delayed vs. immediate; relational vs. nonrelational), participant age range, or the method of normalization of hippocampal volumes. Overall, findings suggest that larger total hippocampal volume relates to better memory performance in children and adolescents and that this relation is similar across the memory types and age ranges assessed. To facilitate enhanced generalization across studies in the future, we discuss considerations for the field moving forward.

Developmental differences in memory reactivation relate to encoding and inference in the human brain

Despite the fact that children can draw on their memories to make novel inferences, it is unknown whether they do so through the same neural mechanisms as adults. We measured memory reinstatement as participants aged 7-30 years learned new, related information. While adults brought memories to mind throughout learning, adolescents did so only transiently, and children not at all. Analysis of trial-wise variability in reactivation showed that discrepant neural mechanisms-and in particular, what we interpret as suppression of interfering memories during learning in early adolescence-are nevertheless beneficial for later inference at each developmental stage. These results suggest that while adults build integrated memories well-suited to informing inference directly, children and adolescents instead must rely on separate memories to be individually referenced at the time of inference decisions.

We Know More Than We Ever Learned: Processes Involved in the Accumulation of World Knowledge

Accumulating information and knowledge is a major task of development. A common assumption is that we build our storehouse of world knowledge, our semantic memory, through direct experience. Although direct experience is involved, to explain fully how we know all that we know, we also must consider processes that allow for integration of information learned in separate yet related episodes of direct learning, as well as inferential processes that operate over integrated representations and permit productive extension of knowledge. In this article, I describe the self-derivation through integration paradigm my colleagues and I developed to model these processes. Using this paradigm, we charted individual and developmental variability throughout childhood and in young adults. Several findings support the contention that the self-derivation through integration paradigm provides a valid model for how we build semantic knowledge, including the observations that performance on the task correlates with and predicts individuals' world knowledge and academic success.

Developmental differences in reactivation underlying self-derivation of new knowledge through memory integration

Self-derivation of novel facts through integration of memory content is fundamental to acquiring new knowledge and a means of building a semantic knowledge base. It involves combining memory content acquired across separate episodes of learning to generate new knowledge that was not explicitly taught in either episode. To self-derive, one needs to reactivate earlier learned memory content upon exposure to related content and then integrate the learning episodes. Previous research found developmental differences in the conditions under which integration occurs. Adults spontaneously integrate whereas 7- to 9-year-old children seemingly integrate only upon direct tests that verbally prompt for integration. Yet it is unclear whether children engage in the preliminary process of reactivation prior to the direct tests. To address this gap in the current research, we developed an eye-tracking paradigm and tested whether adults and 7- to 9-year-old children engage in the process of reactivation prior to direct tests. The direct tests verbally prompted for integration of memory content requiring self-derivation through both open-ended and forced-choice formats. Both adults and children engaged in reactivation prior to the direct tests. The extent of their reactivation predicted their performance on the direct tests. However, adults showed stronger evidence of reactivation and performed better than children on the direct tests. This work contributes to understandings of developmental differences in the underlying processes involved in the development of new knowledge.

Contingency of semantic generalization on episodic specificity varies across development

Semantic memory-general knowledge of ideas and concepts-includes generalization processes that support inference. Episodic memory, on the other hand, preserves the specificity of individual events by binding together unique combinations of elements from an episode and relies on pattern separation to distinguish similar experiences. These two memory systems play complementary roles, supporting different mnemonic goals, but the nature and extent of their interdependence is unclear.1,2 Some models suggest that new information is encoded initially as hippocampus-dependent episodic memory and then, either through repetition or gist extraction, becomes semantic over time.3,4 These models also posit a neocortical route to semantic memory acquisition exists that can bypass the hippocampus.3 Both proposed routes are slow learning mechanisms, yet generalization can occur rapidly. Recent models suggest that fast generalization relies, in part, on the retrieval of individual but related episodes.5,6 Such episodic memory gating mechanisms render fast generalization contingent on the memory specificity of instances, a pattern that has been observed in adults.7,8 None of these models take into account the observation that generalization and episodic specificity have asynchronous developmental profiles, with generalization emerging years before episodic memory.9,10 We ask two questions about generalized and specific memory during early childhood: first, is rapid generalization contingent on remembering specific past memories? And second, does the strength or nature of this contingency differ across development? We found that the interdependence of generalization and episodic memory varies across development: generalization success in adults, but not in children, was contingent on context binding.

Habitual sleep is associated with both source memory and hippocampal subfield volume during early childhood

Previous research has established important developmental changes in sleep and memory during early childhood. These changes have been linked separately to brain development, yet few studies have explored their interrelations during this developmental period. The goal of this report was to explore these associations in 200 (100 female) typically developing 4- to 8-year-old children. We examined whether habitual sleep patterns (24-h sleep duration, nap status) were related to children’s performance on a source memory task and hippocampal subfield volumes. Results revealed that, across all participants, after controlling for age, habitual sleep duration was positively related to source memory performance. In addition, in younger (4–6 years, n = 67), but not older (6–8 years, n = 70) children, habitual sleep duration was related to hippocampal head subfield volume (CA2-4/DG). Moreover, within younger children, volume of hippocampal subfields varied as a function of nap status; children who were still napping (n = 28) had larger CA1 volumes in the body compared to children who had transitioned out of napping (n = 39). Together, these findings are consistent with the hypothesis that habitually napping children may have more immature cognitive networks, as indexed by hippocampal integrity. Furthermore, these results shed additional light on why sleep is important during early childhood, a period of substantial brain development.

Self-derivation through memory integration: A model for accumulation of semantic knowledge

Semantic knowledge accumulates through explicit means and productive processes (e.g., analogy). These means work in concert when information explicitly acquired in separate episodes is integrated, and the integrated representation is used to self-derive new knowledge. We tested whether (a) self-derivation through memory integration extends beyond general information to science content, (b) self-derived information is retained, and (c) details of explicit learning episodes are retained. Testing was in second-grade classrooms (children 7-9 years). Children self-derived new knowledge; performance did not differ for general knowledge (Experiment 1) and science curriculum facts (Experiment 2). In Experiment 1, children retained self-derived knowledge over one week. In Experiment 2, children remembered details of the learning episodes that gave rise to self-derived knowledge; performance suggests that memory integration is dependent on explicit prompts. The findings support nomination of self-derivation through memory integration as a model for accumulation of semantic knowledge and inform the processes involved.

Developmental differences in temporal schema acquisition impact reasoning decisions

Schemas capture patterns across multiple experiences, accumulating information about common event structures that guide decision making in new contexts. Schemas are an important principle of leading theories of cognitive development; yet, we know little about how children and adolescents form schemas and use schematic knowledge to guide decisions. Here, we show that the ability to acquire schematic knowledge based on the temporal regularities of events increases during childhood and adolescence. Furthermore, we show that temporally mediated schematic knowledge biases reasoning decisions in an age-dependent manner. Participants with greater temporal schematic knowledge were more likely to infer that temporally related items shared other, non-temporal properties, with adults showing the greatest relationship between schema knowledge and reasoning choices. These data indicate that the mechanisms underlying schema formation and expression are not fully developed until adulthood and may reflect the ongoing maturation of hippocampus and prefrontal cortex through adolescence.

Self-derivation through memory integration under low surface similarity conditions: The case of multiple languages

A primary objective of development is to build a knowledge base. To accumulate knowledge over time and experiences, learners must engage in productive processes, going beyond what is explicitly given to generate new knowledge. Although these processes are important to accumulating knowledge, they are also easily disrupted. Individuals often depend on surface-level similarities, such as visual features, to recognize the relation between learning episodes. When the surface-level similarity is low, performance on tasks that depend on productive processes, such as self-derivation through integration of new knowledge, suffers. The major purpose of the current research was to examine whether presentation of related information in different languages poses a challenge to memory integration and self-derivation due to low levels of surface similarity between episodes of learning through different languages. In Study 1, 62 children (Grade 2; mean age = 8 years 1 month) listened to story passages containing novel facts that could be integrated to self-derive new knowledge. Related passages were presented either through the same language or through two different languages (cross-language condition; Spanish and English). There were no significant differences between presentation conditions. In Study 2, 100 children (Grades 3 and 4; mean age = 9.7 years) heard novel facts in single sentences, again presented in either a same-language or cross-language condition. Whereas third-grade cross-language performance suffered compared with same-language English controls, fourth-grade performance did not. Results suggest that in addition to language proficiency, rich contextual support and experience in a bilingual environment facilitate cross-language integration.