If you're listening to the right bedroom jam, it might not matter if you're being caressed by a human touch or a robotic one: Both would make you blush.
To explore how we react to music and touch, scientists at the Max Planck Institute for Human Cognitive and Brain Sciences set up a series of experiments where people listened to sexy jams and were petted gently by a robot holding a small brush.
Participants listened to 40 lyricless music excerpts: 20 "rather sexy" pieces and 20 "rather non-sexy" pieces. They stuck one arm through a curtain so they couldn't see what was so tenderly stroking them. A machine on the other side turned a wheel with a brush that made contact with the sensitive underside of their forearms.
In the first two experiments, participants weren't told who—or what—was touching them, but a human assistant was present in the room and everything leading up to the experiment (entering the room, seeing brushes on a table on the other side of the curtain, the presence of the other person) led them to believe the assistant must be doing the touching.
In reality, the assistant snuck in a robot with a spinning brush to do the touching, and to keep the sensation constant across all participants. But even with a cold pile of metal and gears doing the stroking, the sexier the music, the sexier people perceived the touch as being.
For the third experiment, using a different group of people that didn't participate in the blind trials, the researchers revealed the robot as the one doing the brushing. It didn't matter, though. People were still into it, when the mood music was sexy enough. They ranked lingering touches as more sexual, and quick brushes as less so.
Lead researcher Tom Fritz told me in an email that another interesting finding of the study was how people ranked music as "sexy" or "non-sexy." Their rankings for what makes a hot song varied across individuals. A couple with the same cultural background or similar personalities might have the same turn-ons when it comes to musical tastes.
"Music seems to change our perception of touch. Certain features seem to be transferred from music to touch," Fritz said in a press release. "These results also illustrate the evolutionary relevance of music as a social technology."
It challenges the popular idea of enjoyment of music as a frivolous "auditory cheesecake," a nice but essentially useless evolution in human history. If it creates a physical reaction that leads to more successful procreation, however, it could be evolutionarily significant—even if it's a robot turning us on.
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