Research conducted by scientists at the University of Portsmouth, in partnership with Nottingham Trent University, examined why humans show signs of stress – such as scratching, nail-biting, fidgeting, and touching their face or hair – which could demonstrate to others that they are in weakened state.
They found that, as well as being able to accurately identify when someone was stressed, people reacted more positively towards to the individuals who showed more signs of stress.
As part of the study, participants were videoed while taking part in a mock presentation and interview which they had to prepare with very short notice. The videos were presented to raters, who were asked to rate how stressed they thought the person in the video was.
Dr Jamie Whitehouse said: ‘We wanted to find out what advantages there might be in signalling stress to others, to help explain why stress behaviours have evolved in humans.
‘If producing these behaviours leads to positive social interactions from others who want to help, rather than negative social interactions from those who want to compete with you, then these behaviours are likely to be selected in the evolutionary process.
‘We are a highly cooperative species compared to many other animals, and this could be why behaviours which communicate weakness were able to evolve.’
Co-author Dr Sophie Milward from the University of Portsmouth added: ‘Our team is currently investigating whether young children also show this sensitivity.
‘By looking at childhood we can understand how difficult it is to detect stress.’