The Disgust Reflex

Defensive Physical and Emotional reactions Are Naturally Triggered By Disgust Reflexes When Faced with Most Rotten Organic Materials

Disgust is a primal human emotion that can reflexively trigger when facing real and imagined dangers that according to studies requires less than a second based on the circumstances of an encounter. Regarding humans, the disgust mechanism uses facial expressions and social circumstances to make snap judgments in situations based on often highly superficial traits to rapidly process social and physical cues.i Disgust reactions are based upon a variety of circumstances which emerge from social encounters with other humans that extend to variances as minute as regional eating habits. Food plays a central role in several gatherings and social environments in which human interact and some disgust related behaviors are tied to the consumption and abstention of specific foods based on preference, religion, and socially developed aversion.

Researchers studying the disgust mechanism were able to illicit responses in participants using food products that were accompanied by a negative written assessment that highlights one of several methods demonstrated how emotions can be influenced. “We conducted a regression analysis to predict the number of beef chips eaten in the first behavioral task (see Table 2). The full model was statistically significant and explained 12% of the variance in the amount consumed. In this task, we made use of the fact that researchers have previously found a negative correlation between people’s food-related disgust and their consumption of meat and fish (Eickmeier et al., 2017). Participants’ food disgust sensitivity emerged as a significant predictor for the amount of meat participants ate. With increasing food disgust sensitivity, the amount consumed decreased.” However, a similar inspection which used food that participants found unpalatable offered reduced disgust reactions to the food if the person fasted before the later testing, hunger seemingly can overcome some disgust reactions.

“From an evolutionary point of view, disgust protects from transmission of infectious disease and suboptimal reproduction. It impacts our hygienic, sexual, and contact behavior.”ii Reproduction presents “the highest infectious risk of any social behavior” due to intimate situations presenting a chance for infections via “bodily fluids”, skin contact, and the opportunity for possible infecting diseases. One review of these behaviors noted that monogamous relationship strategies in part are undertaken based upon disgust sensitivity and “increasing pathogen costs that accompany each new sexual partner.” Such encounters often rest upon sensitivity levels which are based on a host of factors that includes personal hygiene to maximize chances of reproductive success. Despite significant potential dangers for proper socialization, people must develop a range of disgust reactions and moderate the strongest when dealing with “intimates” to promote survival and mental health, without such moderation the natural range of disgust can shift and promote “dysfunctional barriers” that can emerge prevent normal social interactions.

Disgust sensitivity usually serves as a protective and cognitive strategy when undertaken by most and further explains behaviors such the normal distance people observe when interacting socially with others in public. The vast majority of humans strike a balance of personal disgust preferences to include social interactions with familiar people that are naturally considered less threatening in comparison to strangers. This natural mistrust of strangers was demonstrated in one study that found personal aversion to strangers extends to even smells and being exposed to disgusting substances in which the sources are unfamiliar to an observer. Our disgust reaction to unknown “stimuli from strangers” can prove so exceedingly strong it elicits heart rate changes and increased “avoidance behavior”.iii

Mealworms are one of Hundreds of Thousands of Types of Insects that eat Rotting Materials which can Trigger disgust in Humans

The regulation of hygiene is a common triggering mechanism for disgust reactions in most people and “the source effect” extends to even to people that are just unfamiliar. “Some specific phobias and obsessive compulsive disorders are classical disgust-related disorders with a generally increased sensitivity to disgust.” These would include phobias of specific animals or substances that can transmit disease or be considered taboo or disgusting by various humans and notably “obsessive washing is related to enhanced fear of contamination, which results...in the avoidance of situations with the potential risk of contamination.” While disgust plays a role in protective measures it can become a psychological burden if left unchecked by reasonable behavior and social limitations.

Other similar reactions are formed when dealing with environmental dangers and toxic substances triggering a natural revulsion in the majority of tested subjects. “It has been shown that people who are very sensitive towards disgust and contamination are less often affected by infections...Disgust serves as a behavioral immune system is not sensitive to pathogens...Instead, disgust is directed against cues that signal that infection risk might be present whether due to its morphology” and the study further reveals that smells and visual cues reveal the expectation for potential infection. Humans exhibit stark physical defensive reactions within facial reactions as they experience disgust and once a possible source of revulsion is identified several reactions occur as part of “anti-pathogen adaptions”.iv

According to the Royal Society these adaptions are heavily influenced by parental disgust reactions which can influence the development of similar feelings in their children after five years of age. Additionally, familiarity with family members was found to reduce disgust reactions and dealing with offspring or related substances that normally were considered disgusting produced little revulsion in parents. Investigating researchers learned that disgust reactions can emerge from inherited reactions, environment, and socialization while noting that family levels of disgust were similar but parental sensitivity levels alone could not assure outcomes. The same review further states there is little evidence to support that disgust just emerges from neuroticism, parental influences, or is calibrated to the presence of infectious diseases. There likely is a host of factors that in concert produce specific disgust reflexes in humans which together influence avoidance behavior and form anti-pathogen strategies to maximize the assurance of survival. Yet the reaction when founded upon incorrect or pathological motivations can seemingly be a source of needless conflict that potentially might endanger those with overly sensitive disgust reflexes.

Sincerely,
C.A.A. Savastano

References:
i. Pierre Krolak-Salmon, Marie-Anna Henaff, Jean Isnard, Catherine Tallon-Baudry, Marc Guenot, Alain Vighetto, Oliver Bertrand, Francois Mauguiere, An attention modulated response to disgust in human ventral antererior insula, February 14, 2003, Annals of Neurobiology, doi.org/10.1002/ana.10502
ii. Maria Lenk, Gerhard Ritschel, Marion Abele, Peggy Roever, Julia Schellong, Peter Joraschky, Kerstin Weidner, Ilona Croy, The source effect as a natural function of disgust in interpersonal context and its impairment in mental disorders. Scientific Reports 9, Article 4239, March 12, 2019, https://doi.org/10.1038/s41598-019-40802-4
iii. Ibid.
iv. Joshua M. Tyber. Cagla Cinar, Annika K Karinen, and Paola Perone, Why do people vary in disgust, June 4, 2018, The Royal Society, https://doi.org/10.1098/rstb.2017.0204