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Abstract

Despite considerable evidence that neural activity in monkeys reflects various aspects of face
perception, relatively little is known about monkeys’ face processing abilities. Two
characteristics of face processing observed in humans are a subordinate-level entry point,
here, the default recognition of faces at the subordinate, rather than basic, level of
categorization, and holistic effects, i.e., perception of facial displays as an integrated whole.
The present study used an adaptation paradigm to test whether untrained Rhesus macaques
display these hallmarks of face processing. In Experiments 1 and 2, macaques showed greater
rebound from adaptation to conspecific faces than to other animals at the individual or
subordinate level. In Experiment 3, exchanging only the bottom half of a monkey face
produced greater rebound in aligned than in misaligned composites, indicating that for
normal, aligned faces, the new bottom half may have influenced perception of the whole face.
Scan path analysis supported this assertion: during rebound, fixation to the unchanged eye
region was renewed, but only for aligned stimuli. These experiments show that macaques
naturally display the distinguishing characteristics of face processing seen in humans, and
provide the first clear demonstration that holistic information guides scan paths for
conspecific faces.