What grosses out a chimpanzee? The origins of disgust

Origins of disgust

Date:  November 17, 2017

Source:  Kyoto University

Chimps show increased latencies to feed, and tendencies to maintain greater distances from possible contaminants and/or outright refusals to consume food in test conditions, hinting at the origins of disgust in humans.

Chimpanzees do some pretty disgusting things.

In their natural habitats, chimpanzees are known to pick up seeds from feces and re-ingest them. In captivity, some practice coprophagy: the deliberate ingestion of feces. These behaviors usually involve their own fecal matter, or that of their closest family members. If presented with feces and other bodily fluids from others, however, that's an entirely different story.

In 2015, researchers from Kyoto University's Primate Research Institute went to the Primate Center at the 'Centre International de Recherches Médicales de Franceville' (CIRMF) in Gabon to test whether chimpanzees are grossed out by some of the same things as humans, particularly those that are sources of infectious disease.

Avoiding biological contaminants is a well-known manifestation of the adaptive system of disgust. In theory, animals evolved with this system to protect themselves from pathogens and parasites, which are often associated with media or substrates that invoke our sense of disgust. For example, bodily products are universal disgust elicitors in humans, but until now we did not know whether they also elicit similar reactions in our primate cousins.

In a new study published in Royal Society Open Science, researchers found evidence that exposure to biological contaminants -- ie feces, blood, semen -- via vision, smell, and touch, influences feeding choices even in chimpanzees.

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