(A, D) Illustration of the experimental procedure administered to infants and the computational models in (A) Experiment 1 and (D) Experiment 2. Infants and models were habituated to one object and then tested with objects that consisted of either the same or different shape skeleton. Both types of test objects (counterbalanced order) differed in their surface forms from the habituation object. (B, E) Mean looking times for (B) Experiment 1 and (E) Experiment 2. For the habituation phase, results are shown for the first four and last four trials. For the test phase, results are shown for the two types of test objects (i.e. same and different skeletons; 3 test trials each). Error bars represent SE. (C, F) Classification performance for infants and models for (C) Experiment 1 and (F) Experiment 2. Error bars represent bootstrapped confidence intervals, and the dashed line represents chance performance.