Continuities and discontinuities in working memory representations of collections over ontogeny

Working memory, or the ability to maintain and manipulate information such that it can be used to guide behavior, is known to be severely capacity limited, in most circumstances, to about 3-4 objects. Both infants and adults have the ability to surpass these limits by encoding tobe-remembered items in groups or collections, exploiting statistical regularities or conceptual information to devise more efficient coding schema. Despite progress made toward understanding continuities in working memory, little is known about how changes over development interact with the ability to employ maximally efficient mnemonic data structures. Paper 1 demonstrates that although adults can encode at most three mutually exclusive collections that accrue sequentially over time, they can circumvent this limit when items overlap in features (e.g. red and blue circles and triangles) and statistical regularities are introduced among collections defined by a single visual feature (e.g. most red items are triangular and not circular). Adults’ performance suggests they are able to encode items from intersecting collections hierarchically and exploit statistical regularities among collections to reconstruct the numerosities of up to six collections in parallel, exemplifying how efficient coding can radically enhance working memory. Paper 2 demonstrates that young preschoolers can also represent three mutually exclusive collections that accrue in an intermixed fashion over time. Results show that the ability to