How Is Disgust Processed In The Brain?

There is a lot of talk about how happiness, sadness or fear is produced in our brain. But what about disgust? This essential and forgotten emotion has allowed us to survive over the years. We show you how it is processed in the brain.
How is disgust processed in the brain?

Disgust is one of the basic emotions that has helped us survive throughout our evolution. He was one of psychology’s forgotten ones. Nonetheless, we already have enough information about how the brain processes disgust. A feeling of strong aversion towards certain substances or objects, which produces the need to expel it. To keep him away. Or to reject it.

This emotion is universally considered to be one of the six basic emotions. It is identified in all cultures and in people with sensory limitations. She has a characteristic facial expression : raising of the upper lip, frowning and lowering of the corner of the lips.

In addition, it is accompanied by a drop in blood pressure, a decrease in the galvanic response of the skin and nausea. But also a decrease in heart rate, a feeling of aversion, distancing from the object, respiratory changes and characteristic vocalizations (eg “ughh! ”).

A woman overcome with disgust

Nature of disgust

It is important to keep in mind that it is the experience that shapes our brains. As a species and as an individual. So before we had a developed immune system, we had some kind of behavioral immune system.

This more basic system acted as a barrier that protected us from contact with parasites. But also other potential damage to our body.

The advantage that disgust brought us was mainly the avoidance of disease. So while there are cultural differences about what turns us off, the main triggers for this emotion are:

  • Secretions and parts of the body: feces, saliva, blood, wounds, vomiting, feet, etc.
  • Rotten food
  • Some living things like insects, worms, spiders …
  • Some characteristics of unknown or different people
  • Violation of social or moral standards

It is an innate emotion. However,  it must be taken into account that certain aspects of disgust are learned, giving rise to cultural or developmental differences. For example, children up to the age of two do not seem to feel disgust.

However, this could be explained by the fact that, until this age, they are in the care of their parents and our species is born quite immature and vulnerable. Thus, by observing the behavior of the parents, the emotion would develop.

Disgust in the brain

In order to know how the brain processes disgust, we need to take into account two basic regions: the insula and the limbic system (tonsil and hippocampus).

  • The insula receives information from sensory pathways and sends information or stimuli to other structures, such as the limbic system, ventral striatum, and orbitofrontal cortex. This region appears to be responsible for experiencing disgust, as well as recognizing expressions of disgust in other people. For example, in people with Huntington’s disease, where the insula is affected, there are changes in this emotion, and stimulation of the insula causes nausea.
  • The limbic system, and in particular the amygdala, is linked to negative emotional processing, such as fear and disgust, and to learning. In fact, recently, a group formed by members of the University of Granada and the Autonomous University of Baja California detected the specific region of the amygdala that causes the rejection of unpleasant tastes.

How does he treat it?

So far, scientific studies have linked disgust to certain areas of the brain, capturing images of the areas involved. Today, thanks to technologies such as functional magnetic resonance imaging, it is possible to observe how disgust is dynamically processed in the brain.

This is what a group of researchers in Catalonia did a year ago. To do this, 30 people were subjected to a study in which, within the resonance, six minutes of video of food and other unpleasant objects (cockroaches or men eating worms, among others) were presented.

The results showed that even 40 seconds after observing the unpleasant images, the brain continues to process this emotion. In addition, brain imaging has shown that when faced with an unpleasant scene or object, a part of the brain is activated among those indicated above. But almost half of the brain is also activated.

In terms of treatment, scientists have indicated that there are three phases:

  • The stimulus appears and the brain begins to activate defense and protection mechanisms. And this even without the person being aware of it
  • A second phase of conscious alert in which the stimulus is already consciously assessed as negative
  • A third phase of assimilation, in which the emotion of disgust is felt and causes the experience to be stored in memory. This phase can last about 26 seconds
A man about to vomit because he is in disgust

Disgust disorders

It is possible to feel an excessive disgust towards stimuli that would not be supposed to provoke it in the first place. Thus, there are several psychopathological disorders that are related or have a specific component of disgust.

One example is certain anxiety disorders, such as obsessive-compulsive neatness and order, in which there is overly concern about the spread of germs and dirt.

In some phobias, the disgust component is crucial, as in blood phobia or social phobia. As for the latter, it seems that in some cases the person feels a certain repulsion or aversion towards dealing with people. The role of disgust in eating disorders is also studied.

 

Disgust, a forgotten emotion
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