Findings published in the journal Social Cognitive and Affective Neuroscience suggest that lonely people are less drawn to positive social cues — potentially perpetuating their loneliness. The study revealed differences in how lonely versus non-lonely people respond to images of social touch during brain stimulation.
When a person’s social needs go unmet, they feel distressed and lonely. While an unpleasant feeling, loneliness has been suggested to serve the adaptive function of motivating people to seek out social reconnection. But why, then, can loneliness become chronic for certain people?
The authors of the new study tested the theory that when loneliness persists, people may come to experience their environment as threatening. Feeling unable to rely on the environment for help, lonely people protect themselves by withdrawing from connection, perpetuating their loneliness.
“In today’s world, more and more people are suffering from loneliness,” said study author Leehe Peled-Avron of the University of Haifa. “Interestingly, despite the critical importance of human touch to social connectedness, very little was known about the way lonely people perceive social touch. We wanted to see if and how loneliness was connected to social touch – do lonely people crave touch? Or do they refrain from it? We also wanted tp explore the neural mechanisms of these connections.”
The researchers explored how lonely people respond to positive social cues by measuring their reaction time during brain stimulation of the right inferior frontal gyrus (rIFG) — an area of the brain implicated in loneliness and emotional responses to observed social touch.
A sample of 37 people who completed loneliness questionnaires was divided into a high-loneliness group and a low-loneliness group depending on their scores. Each subject participated in a computer task where they were shown 80 images that belonged to one of four categories: two humans engaging in positive social touch (e.g., hug, handshake), two humans near each other but not touching, two objects touching, and two objects near each other but not touching. For each image, participants were asked to press a key to indicate whether the image depicted humans or objects, and their reaction time was logged.
Throughout the task, the participants received transcranial direct current stimulation (tDCS) via electrodes placed on their heads. The participants took part in two different sessions where they received either anodal (excitatory) or sham (brief) stimulation in the rIFG.
The results revealed significant differences in reaction times to the social touch images during the excitatory stimulation. Participants in the less lonely group showed slower reaction times to the human touch images compared to participants in the high lonely group. These differences were not found when participants viewed inanimate objects.
In other words, lonely individuals reacted more quickly to images of human touch than less lonely individuals. This may suggest that the more lonely participants were not distracted by the emotional cue of human social touch. The authors reason that lonely people may have “activated a self-preserving state”, which steered them away from social connection so that excitation of the rIFG did not affect their reaction time to the human touch images.
Interestingly, questionnaire responses revealed that the lonely group reported less liking of positive social touch. This falls in line with the notion that lonely people enter a self-preserving state where they avoid opportunities for social connection, perpetuating their loneliness.
“We found that lonely people report less liking of social touch and are less drawn to social touch,” Peled-Avron told PsyPost. “We stimulated a part of the brain that is connected to social touch processing, and showed a difference in the reaction of lonely individuals and non-lonely individuals, which we interpret to signify that lonely individuals are less emotionally drawn to social touch. We suggest that this might explain how loneliness is perpetuated. We think this is a vicious cycle in which we are not sure which came first – loneliness or the distance kept from positive social interactions, but the two feed off one another, with lonely people avoiding positive social interactions, which in turn exacerbates their loneliness.”
The study was limited by a small sample size and the fact that the loneliness measure was designed to assess chronic loneliness rather than short-term loneliness. Future research is needed to replicate and elaborate on the findings.
“In this study we used a measure of more chronic loneliness over a prolonged period of time and it might be different to look at short term loneliness or compare the effects of long vs. short term loneliness on the responses to social interactions,” Peled-Avron said. “In addition, it could be interesting to add more measurements to explore the emotional reaction of lonely individuals to social touch, for example physiological measures such as heart rate variability.”
“We are still trying to recover from COVID as a society and it will take some time to truly understand the impact that it had on our social lives,” she added. “Both loneliness and social touch were greatly impacted by the global pandemic. This and similar studies are important for us in order to understand our post COVID social lives and in turn treat the new ailments of the post COVID world.”
The study, “Touched by loneliness—how loneliness impacts the response to observed human touch: a tDCS study”, was authored by Nira Saporta, Leehe Peled-Avron, Dirk Scheele, Jana Lieberz, René Hurlemann, and Simone G. Shamay-Tsoory.
