In a new study published in Evolution and human behavior, researchers found that people who exhibited more nonverbal stress behaviors were rated as more sympathetic. People with more social connections were more accurate at detecting stress in others.
In all species, organisms show signs of stress that can be detected by others. From an evolutionary perspective, little is known about the adaptive advantage of showing signs of stress. Stressful behavior, also known as moving around, includes self-grooming, touching the face, scratching the head, and fidgeting with objects, all of which can help a person regulate their stress. Researchers Jamie Whitehouse and colleagues were interested in investigating whether travel behaviors are reliable indicators of stress in humans.
“We wanted to know what benefits there might be in signaling stress to others, to help explain why stress behavior has evolved in humans,” Whitehouse explained in a press release.
“If producing these behaviors 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 this behavior will likely be selected in the evolutionary process. We are a very cooperative species compared to many other animals, and this could be why behaviors that communicate weakness could evolve.”
For their study, Whitehouse and colleagues recruited 31 participants who responded to pre-task questionnaires, provided saliva samples, participated in a stress-inducing task (the Trier-Social Stress Test), provided a post-task saliva sample, and a post-task questionnaire. More than 100 other participants were recruited to act as evaluators. These participants completed the Social Network Index questionnaire to assess social connection and the Berkley expressiveness questionnaire to assess emotional expressiveness. These participants also watched 10 stimuli videos to estimate how stressed individuals were and rated how much they loved the person.
The results of this study show that self-reported stress was positively associated with the raters’ assessment of their stress. The stress ratings were positively correlated with the proportion of displacement behavior, but negatively associated with the proportion and duration of submissive behavior. People who exhibited more travel behavior were judged to be more sympathetic. Cortisol levels from the saliva samples were not associated with self-reported stress, mean stress scores, or other measures.
Displacement behavior appears to mediate the relationship between self-reported stress and mean assessments of stress. There was little difference in travel behavior and assessment between men and women; female actors, however, were rated as slightly more sympathetic.
Whitehouse and colleagues said these findings provide evidence that stress (displacement) behavior affects perceptions of how likable a person is. Their results also show that a person’s ability to accurately assess the stress level of others predicted the size of their social network. People who made more mistakes in assessing stress levels tended to have smaller social networks, and those who made fewer mistakes had larger social networks. However, raters who were most accurate reported having fewer social connections. Whitehouse and colleagues argued that being too accurate in reading the motivations of others may not be a desirable characteristic of a social partner.
Based on their findings, Whitehouse and colleagues noted that there are specific stress behaviors that raters used to determine the other person’s stress level, but the specific behavior could not be determined. This study also shows that moving behavior is a way of transmitting stress to others; however, the exact information communicated is unknown.
Whitehouse and colleagues said that moving behavior could be adaptive by allowing others to anticipate their future behavior or signaling to others that their behavior is unpredictable, since stress-related behavior is linked to risky behavior. Individuals who exhibited less travel behavior may have been rated as less stressed because the raters noticed they had more established relationships. Those who were more stressed may be rated more sympathetic because they are perceived to be more cooperative and potential social partners.
“If the individuals elicit an empathetic response from the raters, this may make them appear more sympathetic, or it may be that an honest signal of weakness may be an example of benign intent and/or willingness to participate in a cooperative rather than competitive interaction, something that could be a ‘sympathetic’ or preferred trait in a social partner,” study co-author Bridget Waller said in a press release. “This fits with the current understanding of expressiveness, which suggests that people who are more ’emotionally expressive’ ‘, being more liked by others, and having more positive social interactions.”
The study, “Signal Value of Stress Behavior,” was authored by Jamie Whitehouse, Sophie J. Milward, Matthew O. Parker, Eithne Kavanagh and Bridget M. Waller.