A team at the Humboldt University of Berlin set up a specially designed ‘tickling area’ and monitored the brain activity and ultrasonic squeaks of rats while they were being tickled.
What did they find?
Rats have previously been observed to give out high-pitched, laughter-like squeaks when being tickled. The Humboldt team confirmed this, finding the laughter response in the rats’ brains to be very similar to that of humans. They also found that if they were put in stressful situations, such as being under a bright light, the rats didn’t chuckle at all.
Why did they do that?
The findings may help to shed light on how negative and positive experiences are processed in the brain and ultimately affect our behaviour, the team says.