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. [Display omitted] •The ability to generalize knowledge to new situations improves from age 3 to age 8•Different aspects of past events promote generalization success across development•Adults, but not children, rely on context memories of past instances to generalize Do we create general knowledge by drawing on memories of specific past experiences? Children learn categories and gain knowledge at rapid rates, despite fragile episodic memory. Ngo et al. show that, although adults’ memories of specific events are related to generalizing, children form new generalizations based on prior semantic knowledge.