There are at least five hormones and brain neurotransmitters, as well recently discovered neural pathways known as “mirror neurons,” that are known to regulate group and social behavior in human beings. As only 20% of human brain function has been full explored and mapped, there are probably many more biochemicals and brain circuits that regulate social interaction that have yet to be discovered. Human beings, like other primates, such as apes, monkeys and gorillas, are fundamentally social beings. Behavioral experiments consistently find that the vast majority of people function very poorly when deprived of contact with their fellow creatures. It is well established that subjecting prisoners to solitary confinement is one of the most severe and least well tolerated punishments that can be inflicted – rating far higher than beatings by guards and other inmates – and some forms of torture.
Oxytocin is the best known chemical influencing social activity, most likely because a nasal spray containing oxytocin, called Liquid Trust, is being heavily marketed by the manufacturer. At present it’s being promoted as a potential treatment to parents of children with Autism and Asperger’s Disorder. The hormone itself is associated with phenomena such as collaboration, altruism, empathy, compassion, parent-child bonding, monogamy, trust and forgiveness. Some researchers believe that oxytocin, rather than testosterone as previously believed, regulates female sex drive (contrary to popular belief female hormones such as estrogen and progesterone, which regulate ovulation and pregnancy, tend to suppress women’s sex drive).
Oxytocin was first synthesized by Vincent du Vigneaud in 1953, for which he received the Nobel Prize for Chemistry in 1955. It’s secreted by the posterior lobe of the pituitary gland and can be made synthetically. Physiologically, it promotes the secretion of breast milk and stimulates the contraction of the uterus during labor. Its structure is very closely related (differing by two amino acids) to a second pituitary hormone called vasopressin, which regulates fluid balance. However both hormones are produced – and result in emotional and behavioral effects – in both sexes.
Oxytocin has been dubbed the “bonding” hormone, primarily as a result of animal experiments, in which males become super attentive to their young following treatment with oxytocin. Oxytocin effects seem to work both ways: high oxytocin (or vasopressin) levels in human beings seem to stimulate bonding and group affiliation – whereas various group activities clearly increase oxytocin levels. And because high oxytocin/vasopressin levels are associated with subjectively pleasurable feelings – people who engage in these activities (gang banging for example) experience a distinct neurophysiological reward for doing so. And are motivated to seek out activities likely to replicate the experience.
Research shows that endorphins, which are opiate-like substances produced by the human brain (as opposed to synthetic opiates like morphine, codeine and heroin), are also increased by social and group activity (as well as by sex, vigorous exercise and creative activities). Whether increasing brain endorphins also stimulates social interaction is less well studied. Although endorphins (which are complex polypeptides) can be synthesized in the laboratory, they are extremely expensive and not as readily available. Research showing the benefits of exercise in the treatment of depression suggest that vigorous physical activity increases endorphins, which in turn elevate mood.
Neurotransmitters, such as dopamine, norepinephrine and serotonin (the same biochemicals affected by antidepressants) also appear to increase with social activity – though these effects have received even less study.
A mirror neuron is a neuron that fires when an animal observes another animal performing a specific action – as if the first animal were performing the action itself. Researchers believe that these neurons are essential in lower animals for learning new skills. Their function in human beings is less clear. It’s hypothesized mirror neurons make it possible for us to make inferences about another person’s mental state – and more importantly develop the capacity for empathy. To be continued.