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Many hallmarks of human intelligence including language,reasoning, and planning require us to draw upon knowledge aboutthe world in which concepts, denoted by words, are organized bymeaningful, semantic links between them (e.g., juicy-apple-pear).The goal of the present research was to investigate how theseorganized semantic networks may emerge in development fromsimple but powerful mechanisms sensitive to statistical co-occurrence regularities of word use in language. Specifically, wetested whether a mechanistic account of how co-occurrenceregularities shape semantic development accurately predicts howsemantic organization changes with development. Using asensitive, gaze-based measure of the semantic links organizingknowledge in children and adults, we observed thatdevelopmental changes in semantic organization were consistentwith a key role for statistical co-occurrence regularities.

Our knowledge of the world is an organized lexico-semanticnetwork in which concepts can be linked by relations, such as“taxonomic” relations between members of the same stablecategory (e.g., cat and sheep), or association between entitiesthat occur together or in the same context (e.g., sock andfoot). Prior research has focused on the emergence ofknowledge about taxonomic relations, whereas associationhas received little attention. The goal of the present researchwas to investigate how semantic organization development isshaped by both taxonomic relatedness and associations basedon co-occurrence between labels for concepts in language.Using a Cued Recall paradigm, we found a substantialinfluence of co-occurrence in both 4-5-year-olds and adults,whereas taxonomic relatedness only influenced adults. Theseresults demonstrate a critical and persistent influence of co-occurrence associations on semantic organization. We discussthese findings in relation to theories of semantic development.

Sensitivity to statistical co-occurrence regularities is presentfrom infancy. This sensitivity may contribute to learning inmany domains, including category learning. However, priorresearch has not examined whether everyday input conveyscategory-relevant statistical regularities. This study assessedwhether statistical regularities relevant to real-world categoriesare present in a commonly experienced source input –children’s picture books. We focused on animal categoriesbecause this is a domain in which children receive muchexposure from an early age, while simultaneously holdingpersistent misconceptions about category membership beyondpreschool years. Analysis of 80 books revealed that they: 1)Were likely to contain regularities from which individualspecies categories (e.g., “chicken”) might be learned, but 2)Were unlikely to contain regularities from which broadertaxonomic categories (e.g., “bird”) might be learned. Thesefindings point to a paucity of taxonomically-relevant statisticalregularities that may contribute to persistent taxonomicmisconceptions.

The organization of knowledge according to relations betweenconcepts is critically involved in many cognitive processes,including memory and reasoning. However, the role oflearning in shaping knowledge organization has received littledirect investigation. Therefore, the present study investigatedwhether informal learning experiences can drive rapid,substantial changes in knowledge organization in children bymeasuring the effects of a week-long Zoo summer camp versusa control camp on the degree to which 4- to 9-year-oldchildren’s knowledge about animals was organized accordingto taxonomic relations. Although taxonomic organization didnot differ at pre-test, only Zoo camp children showed increasesin taxonomic organization at post-test. These findings providenovel evidence that informal, real-life learning experiences candrive rapid knowledge organization change.