Injustice, dirt and bitter food cause the same reaction
Canadian psychologists have proved that aversion to injustice and bitter food have a common origin and a single physiological mechanism. Psychologists Hana Chapman and her colleagues from the University of Toronto claim that they have managed to prove that one and the other are just as disgusting. Sometimes it is said that beating the obviously weak, taking money from the poor, the sight of bloody vomit on the bed and the taste of quinine in the mouth are equally disgusting.
The work of Canadian scientists is published in the latest issue of Science. Scientists compared the reaction of facial muscles to bitter liquids, disgusting images and financial offers insulting human dignity. The reaction came out exactly the same. According to the authors of the work, among all the facial movements that they studied (their list, however, is not given in the article), there was only one truly universal sign of aversion to gorky. This is the movement of the lifting muscles of the upper lip, which, in addition to their nominal function, also wrinkle the nose and deepen the fold under it. The electrical potential generated by the contraction of this muscle was used to measure the intensity of unpleasant sensations.
Then the scientists made sure that exactly the same signal occurs when the subjects (these were already other volunteers) are shown any disgusting images – open wounds, dirty toilet bowls, nasty insects and other things. The result was the same muscle contraction and the same values of electromyography (measurement of the electrical potential on the muscles). But for just sad, but not disgusting images – photos of homeless people, road accidents, terminally ill and lost people – the reaction was negative, but without lifting the upper lip. So the community of disgust from bitter and from sewage can be considered proven, Canadian psychologists are sure.
And then came the turn of the most important test – aversion to the morally unacceptable. As the latter, scientists have chosen injustice, having modeled it in the standard psychological game "Ultimatum". The result was still the same: a clear correlation between the potential on levator labii and the level of disgust, which also correlated perfectly with the "unfairness" of the offer.
Hence, Chapman and her colleagues draw their main conclusion: morally unacceptable actions "cause the same disgust as carriers of diseases and unpleasant taste." Not quite so, psychologists Paul Rozin and his colleagues from the University of the American State of Pennsylvania note in the commentary accompanying Chapman's article. The work of Canadians shows only that the three stimuli studied (bitter taste, uncleanness and injustice) cause the same response.
Maybe impurity and injustice are processed by the brain separately and just trigger the same reaction – the same one that automatically provokes a bitter taste. Or maybe the body has adapted the same evaluation system for processing moral stimuli as for hygienic stimuli. The latter option looks more plausible considering that the same organism has adapted a single system of reaction to all three types of stimuli – oral, hygienic and moral. Their external manifestations are indistinguishable – there are no questions for Chapman here.