The communicative functions of touch in humans, nonhuman primates, and rats: a review and synthesis of the empirical research (2006)

Hertenstein, M. J., Verkamp, J. M., Kerestes, A. M. et al.

Abstract

In social situations, nonhuman primates use touch to modulate stress. Specifically, grooming relieves the stress associated with aggression, social relationships, mounting, sexual mounts, and embraces, which then, in turn, promotes the formation and maintenance of relationships. Touch, then promotes physical and emotional homeostasis. Touch among conspecifics is especially effective during times of social agitation. These tactile interactions modulate socially induced stress by directly interrupting stressful stimuli in nonhuman primates. Tactile stroking is more frequent than is picking or other forms of grooming. This may be because of its apparent calming effect. The presence of grooming reduces an animal?s heart rate and results in fewer displacement activities to reduce stress.The role of touch is central to the resolution of hostility and aggression. One of the most common strategies for nonhuman primates to resolve conflicts is through reconciliation. Touch is commonly accepted as an important postconflict strategy. Common touches in reconciliation include grooming, mounting, and clasping. Reconciliation is thought to reduce stress because it reduces the uncertainty that subsequent aggression between conspecifics will transpire.