'Some rats don't like being tickled,' scientists newly report

Joy and rats are tickled, at a high frequency as inaudible to the human ear by increasing the 'laughter' is known . However, contrary to previous findings, 'some rats don't like being tickled,' a new research team at the University of Bristol in the United Kingdom reported.

Rat 50 kHz calls reflect graded tickling-induced positive emotion --ScienceDirect
https://www.sciencedirect.com/science/article/abs/pii/S0960982220312288

September: Rats emotional response | News and features | University of Bristol
https://www.bristol.ac.uk/news/2020/september/rats-emotion.html

Not all rats like to be tickled, scientists discover --CNET
https://www.cnet.com/news/not-all-rats-like-to-be-tickled-scientists-discover/

In 2016, biologists at Humboldt University of Germany conducted an experiment in which a thin wire was inserted into the brain of a rat and tickled while measuring the activity of neurons, demonstrating that 'rats laugh at high frequencies when tickled.' did. During this experiment, there were cases where tickled rats chased the hands of researchers in search of being tickled.

Eavesdrop on Ultrasonic Rat Giggles-YouTube


However, a research team at the University of Bristol has shown in a new experiment the existence of 'rats that don't like being tickled.' This new experiment is to 'measure the reaction by actually ticking the rat', and the research team is using the 'Affective Bias Test' to measure the effect in animal experiments such as antidepressants. The response of tickled rats was measured by the emotional evaluation standard.

As a result of this emotional bias test, it was found that 'the laughter that the rat raises when tickled accurately reflects the degree of joy of the rat.' The rats that laughed the most showed the most positive feelings for tickling, and the individuals who did not laugh were found not to enjoy tickling.

Professor Emma Robinson of the University of Bristol, who led this study, said, 'The laughter that a rat makes when it is tickled is an easy-to-measure index that accurately reflects the emotional experience of the rat. Rats that can be measured from laughter The emotions of the rat are considered to be the same except when ticking, so the laughter of the rat can improve the welfare of the rat in the laboratory. '