Writing in Royal Society Open Science Eiluned Pearce and colleagues reported the results of a study on social bonding in singing and non-singing (crafts or creative writing) adult education classes over seven months. Participants were asked to rate their closeness to their group and their affect, before and after their class, at three time points (1, 3 and 7 months). The results showed that although singers and non-singers felt equally connected by the end of the study, singers experienced much faster bonding and had a significantly greater increase in closeness, even at month 1. However the increased rate of bonding in the singing group was not reflected in changes in pain threshold, a proxy measure of β-endorphin levels. The findings suggest that the capacity of singing to bond groups of relative strangers in humans may have played a role in the evolutionary success of modern humans over their early relatives.
In another paper, published in Biology Letters, Bronwyn Tarr and colleagues studied the effect of exertion and synchronous dance movements on social bonding and β-endorphin levels (measured using pain thresholds as a proxy marker). They found that both exertion and synchronous movement increased ratings of social bonding and increased pain thresholds. The effect of bonding was directed only towards fellow participants of the dance (the ‘in-group’), rather than towards the ‘out group’ despite these being known to the participants and regarded as potential friends. Dance can be both synchronous and exertive at once. The results suggest that dancing, which is widespread in human cultures, may have played a role in the evolution of human societies. Potentially, the activation of the endogenous opioid system through synchronized behaviour might also be instrumental in other social aspects of animal behaviour (e.g. the highly synchronized courtship rituals of grebes) and an area for further study.