Figure 2.

Stimulus construction. (A) Our face set was built out of a pool of 180 exemplars of different facial features. Each experimental block of 30 different faces was built from 15 exemplars of each feature. (B) We drew two combinations of these facial features with the sole constraint that across the two subsets of 15 faces, no face stimulus shared more than one facial feature with any of the other faces. In this example, within each column, faces shared the same eyes (and only this feature). Inter-eye distance was decreased in the first subset, and increased in the second subset. This procedure was repeated 12 times so that all the 180 features were used once. (C) Mean faces in the two conditions of inter-eye distance, showing that only this feature varied across the two conditions.