ReviewThe social role of touch in humans and primates: Behavioural function and neurobiological mechanisms
Section snippets
What is grooming for?
Grooming, in primates as in most species, is all about physical touch. The actions are typically bimanual, involving sweeps with one hand interspersed with plucking movements by the other (Sparks, 1967). The plucking movements are directed at skin debris (scabs, skin flakes), spots, blemishes, and the occasional ectoparasite such as a tick or leech, or at vegetation caught in the fur. These movements have two particular characteristics: they are very rhythmic, and the plucking often involves
The social brain and the nature of primate relationships
Primates have unusually large brains for body size compared to other vertebrate groups, and over the past decade or so there has been considerable interest in why this should be. The consensus is now that the explanation lies in the complexity of primate social life. Originally proposed as the Machiavellian Intelligence Hypothesis (Byrne and Whiten, 1988), this was subsequently developed in quantitative form as the social brain hypothesis based on a demonstration that both social group and
The psychopharmacology of grooming
One of the striking behavioural features of grooming in those species that devote very substantial amounts of time to this activity is the fact that an animal who is being groomed can become so relaxed it can quite literally fall asleep. This seems to reflect the fact that social grooming has a number of physiological effects that include a reduction in the heart rate and a lowering of behavioural indices of stress (indexed as rates of scratching and yawning) (Goosen, 1981). Schino et al. (1988)
Discussion
Taken together, these findings suggest that oxytocin (but not vasopressin?) might function in a similar way to endorphins in producing a sense of calmness and contentedness. However, if so, it is far from clear what the causal sequence is here, since most of the circumstances that stimulate the production of oxytocin (mating, birth, breastfeeding, stroking) all involve mechanical stress, and are thus also likely to trigger the release of endorphins. Since neuroendocrines often operate in
References (96)
- et al.
The oxytocin antagonist 1-deamino-2-d-Tyr(Oet)-4-Thr-8-Orn oxytocin reverses the increase in the withdrawal response latency to thermal, but not mechanical stimuli following oxytocin administration or massage-like stroking in rats
Neurosci. Lett.
(1995) - et al.
Neural correlates of pair-bonding in a monogamous primate.
Brain Res.
(2007) - et al.
The VIa vasopressin receptor is necessary and sufficient for normal social recognition: a gene replacement study
Neuron
(2005) - et al.
Genes, brains and mammal social bonds
Trends Ecol. Evol.
(2005) - et al.
Maternal time budgets of gelada baboons
Anim. Behav.
(1988) Peptides in the limbic system: neurochemical codes for coordinated adaptive responses to behavioural and physiological demand
Progr. Neurobiol.
(1993)Neuropeptide families and their receptors: evolutionary perspectives
Brain Res.
(1999)Is social attachment an addictive disorder?
Physiol. Behav.
(2003)- et al.
Neuropeptides and the evolution of social behavior
Curr. Opin. Neurobiol.
(2000) - et al.
Beta-endorphin concentrations in cerebrospinal fluid of monkeys are influenced by grooming relationships
Psychoneuroendocrinology
(1989)