Brief touch is different from a massage: insights from nonhuman primates

Recent findings have shown that the neurophysiological mechanisms involved in human massage and caress are similar to those involved in grooming of nonhuman primates. In contrast, little is known about the neurophysiological mechanisms of brief touch in both human and other primates. Here we review evidence for brief touch in nonhuman primates and contrast its patterns and potential functions with those better known of grooming. We show that brief touch is not an affiliative behavior as it functions to assess the competitive tendencies of unfamiliar individuals and former opponents, to test the state of a social relationship and to signal benign intent. Thus, brief touch plays an important role, complementary to that of grooming, in the regulation of social relationships.