Disgust (, from Latin , ) is an emotional response of rejection or revulsion to something potentially contagious or something considered offensive, distasteful or unpleasant. In The Expression of the Emotions in Man and Animals, Charles Darwin wrote that disgust is a sensation that refers to something revolting. Disgust is experienced primarily in relation to the sense of taste (either perceived or imagined), and secondarily to anything which causes a similar feeling by sense of smell, touch, or vision. Musically sensitive people may even be disgusted by the cacophony of inharmonious sounds. Research has continually proven a relationship between disgust and anxiety disorders such as arachnophobia, blood-injection-injury type phobias, and contamination fear related obsessive–compulsive disorder (also known as OCD).
Disgust is one of the basic emotions of Robert Plutchik's theory of emotions, and has been studied extensively by Paul Rozin. It invokes a characteristic facial expression, one of Paul Ekman's six universal facial expressions of emotion. Unlike the emotions of fear, anger, and sadness, disgust is associated with a decrease in heart rate.
Evolutionary significance
It is believed that the emotion of disgust has evolved as a response to offensive foods that may cause harm to the organism. A common example of this is found in human beings who show disgust reactions to mouldy milk or contaminated meat. Disgust appears to be triggered by objects or people who possess attributes that signify disease.
Self-report and behavioural studies found that disgust elicitors include: body products (feces, urine, vomit, sexual fluids, saliva, and mucus); foods (spoiled foods); animals (rats, fleas, ticks, lice, snakes, cockroaches, worms, flies, spiders, pigeons and frogs); hygiene (visible dirt and "inappropriate" acts [e.g., using an unsterilized surgical instrument]); body envelope violations (blood, gore, and mutilation); death (dead bodies and organic decay), hard diseases and disasters; visible signs of infection
The above-mentioned main disgust stimuli are similar to one another in the sense that they can all potentially transmit infections, and are the most common referenced elicitors of disgust cross-culturally. Because of this, disgust is believed to have evolved as a component of a behavioral immune system in which the body attempts to avoid disease-carrying pathogens in preference to fighting them after they have entered the body. This behavioral immune system has been found to make sweeping generalizations because "it is more costly to perceive a sick person as healthy than to perceive a healthy person as sickly". Researchers have found that sensitivity to disgust is negatively correlated to aggression because feelings of disgust typically bring about a need to withdraw while aggression results in a need to approach. This can be explained in terms of each of the types of disgust. For those especially sensitive to moral disgust, they would want to be less aggressive because they want to avoid hurting others. Those especially sensitive to pathogen disgust might be motivated by a desire to avoid the possibility of an open wound on the victim of the aggression. Those sensitive to sexual disgust must have some sexual object present to be especially avoidant of aggression. Based on these findings, disgust may be used as an emotional tool to decrease aggression in individuals. Disgust may produce specific autonomic responses, such as reduced blood pressure, lowered heart-rate and decreased skin conductance along with changes in respiratory behaviour.
Research has also found that people who are more sensitive to disgust tend to find their own in-group more attractive and tend to have more negative attitudes toward other groups. This may be explained by assuming that people begin to associate outsiders and foreigners with disease and danger while simultaneously associating health, freedom from disease, and safety with people similar to themselves.
Taking a further look into hygiene, disgust was the strongest predictor of negative attitudes toward obese individuals. A disgust reaction to obese individuals was also connected with views of moral values.
Domains of disgust
Tybur, et al., outlines three domains of disgust: pathogen disgust, which "motivates the avoidance of infectious microorganisms"; sexual disgust, "which motivates the avoidance of [dangerous] sexual partners and behaviors"; and moral disgust, which motivates people to avoid breaking social norms. Disgust may have an important role in certain forms of morality.