Somatic Marker Hypothesis - Research Background

Research Background

In economic theory, there is a tendency to model human decision-making as being devoid of emotions, involving only logical reasoning based on cost-benefit calculations. Such theories assume that individuals have the time, knowledge and information processing power to make optimal decisions. In contrast to this idealization, the somatic marker hypothesis proposes that emotions play a critical role in the ability to make fast, rational decisions in complex and uncertain situations.

Patients with frontal lobe damage (e.g., Phineas Gage) provided the first evidence that the frontal lobes were associated with decision-making and social conduct. Frontal lobe damage, particularly to the VMPFC, results in impaired abilities to organize and plan behavior, learn from previous mistakes, and behave in a socially appropriate manner. Patients with damage to the VMPFC develop severe impairments in both personal and social decision-making that can result in choosing unsuitable friends, partners, and activities. In fact, these patients appear to lack concern for other individuals, which resembles a mild form of sociopathy. Surprisingly, patients with VMPFC damage have normal intellect in terms of working memory, attention, and language comprehension and expression.

VMPFC patients also have difficulty expressing and experiencing appropriate emotions. This led Antonio Damasio to hypothesize that decision-making deficits following VMPFC damage result from the inability to use emotions to help guide future behavior based on past experiences. This damage prevents rapid emotional signaling to bias behaviors toward appropriate responses to simplify the process. Consequently, VMPFC damage forces those afflicted to rely on slow and laborious cost-benefit analyses for every given choice situation, which degrades accuracy and response-time.