Figure S1.

Behavioral effects, related to Figure 1

(A) We included an implicit hierarchical structure in the task, such that large silhouettes could often be decomposed into hierarchical building blocks. These hierarchical building blocks were never introduced explicitly but allowed for a more efficient construction of larger objects once learned.

(B) Subjects displayed a preference for such “hierarchical chunking,” such that on the second training day they used a hierarchical building block configuration to construct larger silhouettes more often than predicted by chance.

(C) Preferences for hierarchical chunking for the individual hierarchical building blocks.

(D) At the end of the experiment, subjects completed a behavioral questionnaire to indicate similarity judgments between silhouettes. We found these similarity judgments were influenced by visual similarity, namely shape (pixel) and size overlap, and also by “construction similarity,” namely by the overlap of (basic/hierarchical) building blocks (BBs) across (small/large) silhouettes.