Figure 8
(a) The training stimulus set consists of five targets and five distractors. One group of animals received the stimulus pairs in the shown order, whereas the second group received them in reversed order to ensure that there is no effect of stimulus order. (b) All testing stimuli. The upper two rows visualize the testing targets (i.e., faces) with a different number of correct contrast features. The top five targets have 6 correct contrast features, whereas the bottom row of faces includes targets with 12 correct contrast features. The lower three rows visualize the testing distractors (i.e., non-faces), again with a different number of correct features (1, 6 and 12) corresponding to our hypotheses.
