The Kissing Brain: Investigating the Neuroscience of Romance

New study uses mobile EEG to investigate real-life emotions in romantic couples.

Posted Feb 10, 2021 | Reviewed by Gary Drevitch

Think about the last situation in which you experienced an intense positive emotion.

Did it involve another person?

The answer to this question is highly likely to be “Yes." While negative emotions like sadness are often experienced when we are lonely, positive emotions often (but not always) occur while we interact with other people, like family, friends, or romantic partners. Despite this, neuroscientific studies aimed at investigating human emotions often involve people sitting in a laboratory alone while looking at pictures of emotional scenes. While this highly controlled environment has several benefits when conducting psychological experiments, it has one big drawback: Pretty much anyone can tell that looking at a picture of two people kissing is not the same as passionately kissing another person yourself.

A new study, of which I have been one of the co-authors, has just been published in the journal Scientific Reports (Packheiser et al., 2021). The scientists used advanced mobile EEG technology to record the brain waves of romantic couples while they were actually embracing each other, kissing each other, and while they listened to an emotional speech about their love prepared by a partner. The brain waves in these emotional situations were contrasted with neutral control conditions. For embracing, participants had to embrace a body pillow instead of the partner and for kissing they had to kiss their own hand. For the speech condition, participants had to listen to the weather report instead of the emotional text prepared by the partner. Altogether, these situations were much more akin to real emotional situations than looking at emotional pictures, as in many classic emotion science studies.

This new study design was made possible by advances in EEG technology. EEG stands for electroencephalogram, a technique in which participants wear caps outfitted with electrodes that indirectly measure electric activity in the brain. This way, scientists can get insights into what happens in the brain when someone is doing an experimental task. Classic stationary EEG systems could not be used in situations that involve dynamic movements like an embrace, as this would generate too much noise in the data. Newer mobile EEG systems like the one used in this study have been adapted so they can be used even for situations in which movements are involved – like most romantic interactions with a partner.

What did the results of the study show?

The EEG data showed that positive emotional situations with a partner, in particular kissing each other and listening to a romantic speech, involved stronger brain activation in the frontal part of the left hemisphere of the brain compared to a neutral control condition. This finding is in line with the so-called valence model of emotion processing in the brain which postulates that positive emotions are primarily processed by the left side of the brain. In contrast, negative emotions are primarily processed by the right side of the brain. The study is the first evidence that this classic model also applies to real-life emotional situations.

Of course, this study is only the first using this new mobile EEG technology to understand what happens in the brain when two people love each other. It can only be hoped that more research using this technology is conducted to unravel the mysteries of the brain in love.


Packheiser, J., Berretz, G., Rook, N. et al. Investigating real-life emotions in romantic couples: a mobile EEG study. Sci Rep 11, 1142 (2021).