The research team, based at the University of Wisconsin-Madison, asked a group of girls to take part in a stressful situation involving public speaking and maths tests. One of the reasons why female subjects were chosen was because the researchers felt that they were likely to be more accepting of physical touch than boys. After the test, the girls either received direct physical contact with their mothers, or merely talked to them on the phone. The scientists then measured the levels of the hormone cortisol, which is released in response to stress, and oxytocin, which is associated with emotional bonding and thought to reduce stress, amongst other effects.
The research revealed that oxytocin levels increased to comparable levels in the group who spoke to their mothers on the phone as compared to those who had direct physical contact. Although cortisol levels fell more rapidly in the girls who were allowed to see their mothers, there was still a very significant reduction in those who only chatted on the phone, suggesting that vocal contact alone is enough to significantly reduce stress in girls placed in stressful situations.
The research breaks new ground in the investigation of how our hormonal balance affects – and is affected by – the social relationships we form. Professor Leslie Seltzer, who led the research team, is now investigating the effects of other communication methods, such as text messaging, on oxytocin levels. She also hopes to see the research diversify into other species and states that “On the one hand, we’re curious to see if this effect is unique to humans. On the other we’re hoping researchers who study vocal communication will consider looking at oxytocin release in other animals and applying it to broader questions of social behaviour and evolutionary biology."