Women have evolved to "tend and befriend" when under stress, rather than to elicit the "fight or flight" response, according to a leading psychologist.
Her research findings suggest that "fight or flight" may be more specific to male stress responses than previously assumed.
The "tend and befriend" response involves increases in nurturing behaviours, such as looking after children and seeking supportive social contact with friends and family, according to findings presented yesterday to the European Health Psychology Conference at NUI Galway.
"Under stress, women secrete a 'bonding' hormone called oxytocin from the brain," explained Prof Shelley Taylor, of the University of California, Los Angeles.
"Oxytocin is produced in high quantities at childbirth and acts as a biological signal to seek out others and improve social support."
Men also secrete oxytocin, although at much lower levels than women. In addition, oestrogen, a female hormone, enhances the effect of oxytocin, rendering women much more susceptible to its effects.
Previous research had largely focused on the "fight or flight" response to stress.
"This is a very basic response which involves 'revving up' the organism, readying for action," Prof Taylor said. "It is a very individualistic response however, which does not take into account the importance of social interaction to human evolution, particularly for women. Humans have evolved as social organisms and the 'tend and befriend' system for managing stressful events makes sure we are embedded in social systems."
Social support had been demonstrated to have positive effects on health, including improved wound-healing and reduction in the impact of infectious diseases.
It even had beneficial effects on chronic conditions such as diabetes, heart disease and some cancers, according to Prof Taylor.
"Social support reduces people's physical response to stress. This is important, as prolonged activation of these stress systems can increase the risk of chronic disease. The negative effects of stress on disease are more severe when these social defence systems break down.
"There is also evidence that social support has a more direct effect on health, as well as its function in reducing stress."