What are Somatic Markers?

Somatic markers trigger physical reactions to emotional stimuli. The word somatic is related to the word soma, which means "of the body." When a person feels a particular emotion, a somatic marker triggers the body to select the most biologically advantageous option for the situation. Antonio Damasio, a renowned neuroscientist, became known for his somatic-marker hypothesis showing that through somatic markers, emotion is inextricably linked with rational decision making.

Somatic-Marker Hypothesis

• In his somatic-marker hypothesis, Damasio investigated people who have damaged limbic systems. The limbic system, or the prefrontal cortex of the brain, is the source of emotions and that which interprets somatic marker feedback. Although people with damaged limbic systems tested well in intelligence and language, they repeatedly made errors in judgment and behaved inappropriately in social situations. This, Damasio claimed, showed the inability of the compromised emotional mind to use somatic markers, proving his theory that rational thought and emotions are intrinsically linked.

People wiith No Limbic System Damage

• People with no damage to their limbic systems have what are considered normal, or gut, reactions to situations. If a dog bites a person, that person will remember the pain associated with the bite. When that person sees a dog again, before he or she can even think about it, the memory of the pain triggers a somatic marker, and an automatic fear of dogs will surface. The more times the subject sees a dog, the stronger the automatic trigger of the somatic marker causing fear becomes. As Damasio said, when a "negative somatic marker is linked to a particular future outcome, it becomes an alarm bell."

Prefrontal Cortex Damage

• Those with damage to the emotional center of their brains often have trouble with judgment and control of social behavior. Because somatic markers are not triggered when such a person encounters positive or negative emotions, they cannot respond appropriately, not having remembered the negative impact of a prior occasion. For instance, if someone with a damaged limbic system wants to go out to dinner, that person may not remember the outcome of experiences at certain restaurants, recall where to find the food he desires or even decide what food he desires, thereby making a rational decision of where to eat almost impossible. Damasio's theory here is that an ability to activate somatic markers when ordinary decisions arise marks the inability to decide between good and bad decisions.

Evidence of Hypothesis Validity

• Somatic markers trigger automatic reactions to situations that guide someone to reject a negative response and pursue a positive action. Damasio proved that if the part of the brain that triggers somatic markers is damaged, certain aspects of that person's judgment will be faulty. Therefore, he said, this shows an inseparable connection between emotions and rational thought.