Figure 1.

Task design. Left, The study phase consisted of five study blocks in which 80 faces were presented in each block. Each face was displayed for 4 s and participants made a gender judgment. Face viewpoint was either held constant across study blocks (fixed condition) or a different viewpoint was shown in each study block (variable condition). Right, Surprise memory test consisted of 80 previously studied faces and 80 nonstudied faces. Among the previously studied faces, half were shown from a repeated viewpoint and half were shown from a novel viewpoint. For faces studied from variable viewpoints, the repeated viewpoint was the same as the viewpoint used in the fifth study block. Participants made a memory judgment using a five-point recognition confidence scale (1, sure new; 5, sure old).