Disgust is an evolved psychological system that protects organisms from pathogens through avoidant behavior, according to a 2011 study published in the Philosophical Transactions of the Royal Society B.
The study, entitled "Disgust as an adaptive system for disease avoidance behavior," suggests that this 'behavioral immune system' is present in many species that exhibit universal features of hygienic behavior in response to the cues of possible infection.
Recently, a study investigated whether those with greater pathogen disgust sensitivity will be exposed to fewer pathogens in their local environment, and thus will suffer fewer infections.
The study "Pathogen disgust sensitivity protects against infection in a high pathogen environment" was published in the Proceedings of the National Academy of Sciences on February 15.
Disgust Functions as a Protection Against Infection
According to a press release from Washington State University, the researchers from WSU and University Colorado examined data from households of three indigenous Ecuadorian Shuar communities that were all located in the high-pathogen environment.
However, they all differ in the levels of economic development and participation in subsistence activities like hunting.
They found that communities with higher economic development who have access to clean water and foods purchased in the market benefit from the protective effect of disgust to avoid things that repulsed them.
But the case of communities that relied heavily on hunting small-scale agriculture is different. People in these communities must encounter potential pathogens to acquire food, like exposure to animal feces and contaminated water. That means they have lower levels of disgust.
"We found that people with higher levels of disgust had lower levels of inflammatory biomarkers that were indicative of having bacterial or viral infections," said Washington State University associate professor of anthropology Aaron Blackwell who is the co-author on the paper.
"While the study shows that disgust functions to protect against infection, it also showed it varies across different environments, based on how easily people can avoid certain things."
Why It Does Not Work On All Pathogens
Blackwell pointed out that the protective effect of disgust does not work for all pathogens. For example, when your job is hunting and growing your food, pathogens in the soil are hard to avoid.
Moreover, Futurity reported that disgust is also unlikely to help during the current COVID-19 pandemic because so much of the spread are asymptomatic, which means that often there are no obvious signs of the infection to trigger disgust that will make people avoid potential carriers of the virus, said co-author Theresa E. Gildner.
Governments and health agencies have increased awareness of pathogen avoidance behaviors, like frequent hand washing and social distancing. Although, this might also depend on living conditions, like having access to clean water and soap.
The researchers said they intend to continue exploring the relation of disgust to the health condition, whether it changes with age, living conditions, and exposure to sources of infection.
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