Love is still something ‘magical’. But researchers have now succeeded in scientifically substantiating mutual attraction.

Choosing the person you want to spend the rest of your life with is based on a gut feeling; a so-called ‘click’. With one you feel it, with the other you don’t. But how does this sense of romantic connection actually come about? Although love is often described as something ‘magical’, psychologist Eliska Prochazkova of the Leiden Institute for Brain and Recognition a bold move. Because she looked in a new study, published in the journal Nature, whether it is possible to predict mutual attraction during blind dates.

gut feeling

It is quite difficult to substantiate why you feel a romantic click with someone. Often it has to do with a ‘gut feeling’. “This is often expressed as a sensation in the body,” Eliska Prochazkova told “This kind of attraction is hard to regulate, fake or put into words. But it seems to be an important factor that overrides rational decisions when it comes to partner choice.” The researchers hypothesized that people’s physiology must be the best way to measure that “sensation in the body.” “Instead of looking at the level of arousal (how fast your heart beats) when you’re with someone, we thought how your physiology ‘clicks’ (matches) with another person is a better predictor of attraction,” says Prochazkova . “And that’s exactly what we found.”


To unravel the mystery of the mutual attraction, the researchers built “dating cabins” at various events where they asked single young people on a blind date. A total of 140 young people took part in the experiment, who were given a randomly assigned date. Both subjects were given ‘eye-tracking glasses’ that registered their eye movements. Other devices measured skin conductance – or the sweat on your fingers – and heart rate.

Facial expression

You may think that mutual attraction is best read in visible, external cues, such as facial expressions or a knowing look. But the opposite turns out to be the case. “Women in the study made extensive use of these signals in the form of gestures and laughter,” explains Prochazkova. “Men stare more at women; they look longer at the faces, eyes and body. But none of these signals predicted how much someone is attracted to someone else.”


What can you read about mutual attraction? Sweat and heart rate, the researchers conclude. Because the study shows that in people who do see each other, the heart rate and skin conduction synchronize. According to the researchers, it explains why we feel a romantic click with some people and not with others. “We found that on dates who were attracted to each other, the heartbeat synchronized,” says Prochazkova. “If one person’s heart rate rose, the date’s heart rate also rose. And if the heart rate decreased, it also decreased in the other person. The skin conductance followed a similar pattern. Apparently, the attraction between dating partners grows when synchronization takes place at this deeper level.”

Micro expressions

What causes that synchronization? “Scientists are still not 100 percent sure how this synchronization occurs,” Prochazkova says. “But it happens in multiple contexts. For example, mother and child also synchronize the heart rate during skin-to-skin contact and when they play together. Taking over the heartbeat and skin conduction of the other is probably caused by micro-expressions. These are very small signals that are not visible to the naked eye. These can be, for example, small blinks of the eyes, blushing or dilation of the pupil. Although you don’t consciously register these subtle changes, your brain and body do process these micro-expressions, synchronizing the heartbeat and skin conduction. Because you perceive these changes internally, you feel that the other understands you and you get a good feeling.”

Can it be predicted?

So is it possible to predict mutual attraction? The answer seems yes. And not through the facial expressions or facial expressions, but through the synchronization of sweat and heartbeat. A discovery that, according to Prochazkova, is easy to explain. “While people often smile or smile to be polite, people can’t easily control their heart rate or sweat response,” she explains. “This helped us establish the correlation of more sincere exchanges.” This study is therefore the first to show that the ability to synchronize with a partner on a physiological level is an important predictor of sexual attraction during first encounters.


An interesting question is whether the mystery of the romantic click has actually been unraveled. Because does synchronization of the heartbeat and skin conduction first actually take place and then mutual attraction arise? Or is it the other way around: do you first find someone attractive and only then synchronize skin conductance and heart rate? According to Prochazkova, that is not yet fully known. “While the direction between physiological synchrony and attraction is unclear (synchronization can cause attraction or vice versa), we speculate that the ability to synchronize with other people may allow us to embody the affective experiences of others,” she tells us when asked. . “When people perceive another person’s blush or pupil dilation, their own homeostatic reflexes can also be activated. In this way, people can align emotionally and physiologically. It means that one’s ‘gut feeling’ can be defined as estimating the probability of a favorable or unfavorable outcome based on somatic experiences.”

All in all, the researchers are one step closer to understanding romantic attraction. Because the findings indicate that internal signals, such as heart rate and skin conductance, play an important role. “Critically, the results imply that the physiological state of two people can synchronize with mutual attunement,” says Prochazkova. “During these moments, a shared mental state can allow for the feeling of a ‘click’ and attraction.” So it seems that we are now beginning to better understand when and how a romantic click occurs. Will scientists ever be able to fully explain the ‘magic’ behind romantic love? Time will tell.