Task sequence for Experiment 2. Observers fixated a central cross while a sequence of faces was presented randomly on an invisible, isoeccentric ring. Faces were randomly presented at 1.6, 3.9, 14.2, or 21.3 Hz, at set sizes of 4, 12, or 20. The set was followed by a test face that remained on the screen until a response was received. Numbers indicate the distance (in emotional units) each face was from the mean expression, although the sequence (mean expression) was randomized on every trial. Numbers were not visible to participants.