Generalization and the hippocampus: More than one story?

Tracking prototype and exemplar representations in the brain across learning

“…Moreover, our results aligned with those found separately across two studies, replicating the role of the VMPFC and anterior hippocampus in tracking prototype information ( Bowman and Zeithamova, 2018 ) and replicating the role of inferior prefrontal and lateral parietal cortices in tracking exemplar information ( Mack et al, 2013 ). Prior work has shown that the hippocampus and VMPFC support integration across related experiences in episodic inference tasks (for reviews, see Schlichting and Preston, 2017 ; Zeithamova and Bowman, 2020 ). We have now shown for the second time that these same regions also track prototype information during category generalization, suggesting that they may play a common role across seemingly distinct tasks.…”

“…It may be that representations form at multiple levels of specificity to promote flexibility in future decision-making because it is not always clear what aspects of current experience will become relevant ( Zeithamova and Bowman, 2020 ). Consistent with this idea, research shows that category representations can spontaneously form alongside memory for individuals, even when task instructions emphasize distinguishing between similar individuals ( Ashby et al, 2020 ).…”

“…These differing representations may emerge because they allow for flexibility in future decision-making, as abstract representations that discard details of individual items are well suited to making generalization judgments but are poorly suited to judgments that require specificity. Alternatively, prototype representations may emerge as a byproduct of retrieving category exemplars, and they may themselves be encoded via recurrent connections, becoming an increasingly robust part of the concept representation ( Hintzman, 1986 ; Koster et al, 2018 ; Zeithamova and Bowman, 2020 ). Thus, under some circumstances, both prototype and exemplar representations may be apparent within the same task.…”

Contingency of semantic generalization on episodic specificity varies across development

“…These findings align with the idea that category coherence is important for category learning and generalization. 27 Further, accurate item conceptual specificity was associated with greater generalization. Generalization benefitted from accurate memory specificity for the object identities from the individual episodes.…”

Neurocognitive modeling of latent memory processes reveals reorganization of hippocampal-cortical circuits underlying learning and efficient strategies

“…The hippocampus is thought to be particularly important for early stages of learning and memory consolidation 48,49 as well as binding of information together [49][50][51][52][53][54][55] , such as associating addends with sums in addition problems. More broadly, while the intraparietal sulcus (IPS) subdivision of the PPC has been specifically implicated in visuospatial representation and manipulation of numerical quantity in children and adults 1,42,43,[56][57][58][59][60][61] , the hippocampus has been linked to learning and memory across different cognitive domains besides mathematics 62 . Consistent with this view, functional coupling between the hippocampus and frontoparietal brain regions has been linked to the use of memory-based problem-solving strategy and training-related arithmetic performance gains in children 13,39,45,46,56,63 .…”