Touch can soothe, create a sense of security and strengthen bonds, but depending on the context it can also cause anxiety, discomfort or a sense of threat. It can affect us both physically and emotionally.

Researchers from the Institute of Psychology of the Polish Academy of Sciences and Dresden University of Technology in Germany wanted to find out whether a similar response occurs when we are not directly involved in a situation but merely observe touch between two people.

Can watching a hug or an aggressive tug trigger a reaction in our bodies similar to what we would experience ourselves?

To investigate this, the researchers analysed data from 148 people aged 18 to 71 from almost all continents. Before the study, participants completed questionnaires covering, among other things, their tendency to avoid social touch and their awareness of signals coming from their own bodies.

They then watched short videos showing different touch situations. Some depicted positive interactions, such as holding hands or hugging, while others showed unpleasant or aggressive behaviour, including pushing and pulling.

After each video, participants rated their feelings before marking on a digital human silhouette where they had felt a physical reaction and where they had experienced an emotional reaction.

The researchers used these responses to create so-called body maps. Each location indicated by participants was converted into a numerical value and compared with the responses of other people.

The results, published in Scientific Reports, showed a clear difference between physical and emotional reactions.

Physical reactions almost exactly mirrored the location of the contact shown on screen. If a person in the video was touched on the hand, participants primarily pointed to their own hand or arm. If the touch involved a different part of the body, the location indicated on the map changed accordingly.

The maps of emotional reactions looked completely different. These were concentrated mainly in the head and chest, regardless of whether the observed touch was positive or negative.

“Emotional reactions are largely concentrated in the area of the heart and torso, where we can feel many reactions coming from the body, including stomach cramps and changes in heart rhythm. They are completely different from maps of physical sensations, i.e. those directly related to the place where touch occurs,” explains Justyna Świdrak, PhD, from the Institute of Psychology PAS, the first author of the study.

The scientists also observed differences between reactions to positive and negative situations. Positive scenes triggered stronger physical than emotional reactions, while negative scenes produced a stronger emotional response.

“In our study, we show that somatoperception follows two separate paths. On the one hand, there is a physical component: when we see touch, our nervous system somehow reproduces information about it. On the other hand, we have an emotional component that takes place slightly elsewhere,” Świdrak says.

Participants’ individual characteristics also influenced how they reacted. People who reported a greater tendency to avoid physical contact reacted much less strongly to positive forms of touch. However, this relationship was not observed in scenes depicting aggression or unpleasant contact.

In the future, mapping body reactions may help researchers better understand people with social anxiety or neuroatypical people, whose processing of touch may be impaired or different, as well as patients experiencing chronic pain and hypersensitivity to tactile stimuli.

“We can try to implement various types of interventions based on observing touch, even in people who are averse to physical contact. Some pain syndromes also include allodynia, i.e. hypersensitivity to touch. Perhaps in the future, observing touch and then gradually introducing it in a very gentle form could help desensitise to this stimulus,” Świdrak says.

Ewelina Krajczyńska-Wujec (PAP)

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