Darwin was wrong? I didn't expect to come to this conclusion while singing karaoke...

Compiled by: Gong Zixin

What does it feel like to blush?

Due to embarrassment, shyness, shame, pride, etc.

Self-conscious emotions

The face becomes hot and red uncontrollably

No wonder Darwin called blushing

“The most unique and human expression”

Why do we blush?

What are the underlying mechanisms of blushing?

To answer this question, Milica Nikolic and Disa Sauter of the University of Amsterdam in the Netherlands, in a new collaboration with Simone di Plinio of the University of Chieti, used an MRI scanner to explore the neural basis of blushing.

"Blushing is a very interesting phenomenon because we still don't know what cognitive skills are required for it to occur," explains developmental psychologist Nikolic. "There is a view in psychology going back to Darwin that we blush when we think about what other people think of us, and that this involves relatively complex cognitive skills."

Sing karaoke to detect blushing

To reveal the neural activity associated with blushing, the researchers studied blushing by observing activated brain regions in an MRI scanner while measuring cheek temperature (an indicator of blushing). The participants were female adolescents aged 16-20, a group that is particularly sensitive to social judgment. "It is well known that blushing increases during this life stage because adolescents are very sensitive to the opinions of others and fear being rejected or giving the wrong impression," said Nikolic.

To evoke the blushing response in a controlled experimental setting, participants came to the lab for two separate experiments. In the first phase, participants were asked to sing carefully selected difficult karaoke songs, and in the second phase, they watched videos of themselves singing. To make matters worse, participants were also told that an audience would watch the videos with them. Finally, the researchers showed participants videos of another participant with a similar singing level and a professional singer who was disguised as a third participant. At the same time, the participants' brain activity and physiological responses were measured.

The mechanism behind blushing

As expected, the researchers found that participants blushed more, had greater activation in the cerebellum (lobule V) and left paracentral lobe, and showed more time-locked processing to the videos in the early visual cortex when watching videos of themselves compared to watching videos of other participants. These findings suggest that blushing is associated with activation in brain regions involved in emotional arousal, suggesting that it may occur independently of higher-order social cognitive processes.

Effects of experimental conditions on brain activity and brain activity associated with cheek temperature changes

Surprisingly, there was no activation in areas traditionally thought to be associated with understanding one's own or others' mental states. "Based on this, we conclude that thinking about what others are thinking may not be a necessary condition for blushing. Blushing may be part of your automatic arousal when exposed to the environment, related to yourself," Nikolic concludes.

Blushing itself is interesting because it is universal. Some people even have a fear of blushing, such as socially anxious people. When you understand the mechanism of blushing, you can better overcome the fear of blushing.

The researchers say the next step will be to study blushing under different conditions, and to explore the phenomenon even in young children, before they develop the cognitive skills to think about what others are thinking. The findings offer new avenues for future research into self-awareness in infants and non-human animals.