Before we make a decision we assess the possible outcome and incentive value of the choice available to us. In this assessment we use both rational thinking (cognitive process) and emotions. Traditionally decision making is considered as part of rational thinking and motions are not regarded as part of rational thought. But recent researches have clearly demonstrated that emotions influence human judgment and decision making in important ways.
An emotional state can shift an individual away from a decision that might ordinarily be made. When people are in a good mood, they try to maintain the pleasant emotional state by avoiding negative thoughts which causes unpleasantness. This kind of mood maintenance can adversely affect aversion of undesirable outcomes. An individual usually try to avoid loss when he/she is in a positive mood and trying to maintain it. Thus tendency for risk aversion is heightened in positive mood.
Fear can also affect our judgments by heightening risk aversion. Professor Baruch Fischhoff, department of Social and Decision Sciences, Howard Heinz University and his associates Slovic, Lichenstein, Reid, and Combs studied attitudes held about the risks and benefits of different technologies in society. It turned out that judgments about safety of a technology were affected by emotional factors. For example, nuclear power is feared by people in part because the radioactive waste from the technology must be stored for thousands of years in a safe way that prevents contamination of our water and air. It is also feared because the technology can be used to build nuclear weapons with devastating power. The disasters occurred in some nuclear power plants have added to the fear factor of the people. The dread that people feel about nuclear technology causes them to be much more risk aversive than the actual probability of a nuclear accident would warrant. These are the examples of emotions affecting decision making at the conscious level. But there are instances at which the emotions affect decision making in covert or unconscious ways.
Somatic marker hypothesis
|Ventromedial Prefrontal Cortex (red)|
When we face complex and conflicting situations we are unable to decide on the basis of rational thinking only. According to Antonio Damasio, the neuroscience researcher in University of Southern California, somatic markers help us decide in such complex and conflicting situations. This new theory in the cognitive neuroscience is called somatic marker hypothesis. The hypothesis holds that we experience sensations arising from the internal organs. These sensations are called visceral feelings. The visceral feelings guide our decisions based on the anticipated pain or pleasure of the outcomes of the decisions. These visceral feelings are called somatic markers. The signals producing somatic markers are generated in the ventromedial part of the prefrontal cortex (VMPFC) of cerebrum of the brain.
|Brain Stem in green|
In complex and conflicting situations this part of the brain gets activated, signals are sent to internal organs through the brain stem or the “stalk” of the brain and spinal cord and the individual experience visceral feelings which bias the cognitive process of decision making covertly or unconsciously. The somatic markers also influence the decision making overtly or consciously by sending signals to the cortical centers engaged in cognitive process. Damasio proposes that somatic markers direct attention towards more advantageous options, simplifying decision making process. The amygdala, a nucleus in the brain which acts as a hub of emotional reactions is also an essential part of somatic marker system. Therefore damage to the amygdala or the VMPFC would disrupt the action of the somatic markers.
Man learns unconsciously from experiences
The somatic markers are developed during the previous experiences of failures and associated negative emotions such as depression and anxiety. These emotions had created some subtle visceral feelings or sensations arising from the internal organs. The same sensations are produced during complex and conflicting situations. In such situations the somatic markers come into actions and visceral sensations are produced which guide the individual to a quick decision.
According to economic theory, human decision-making is devoid of emotions and involves logical reasoning based on costs-benefit calculations alone. This theory assumes that individuals have unlimited time, knowledge and information processing power and can therefore make perfect decisions. In contrast to economic theory, the somatic marker hypothesis proposes that emotions play a critical role in our ability to make fast, rational decisions in complex and uncertain situations.
Patients with frontal lobe damage 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. Pheneas Gage (1823 – 1860) was an example. He was an American railroad construction foreman now remembered for his improbable survival of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe, and for that injury's reported effects on his personality and behavior – effects so profound that friends saw him as "no longer Gage".
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.
Neurological mechanism producing somatic marker
Emotions, as defined by Damasio, are changes in both body and brain states in response to different stimuli. Physiological changes (e.g., muscle tone, heart rate, endocrine release, posture, facial expression, etc.) occur in the body and are relayed to the brain where they are transformed into an emotion that tells the individual something about the stimulus that they have encountered. Over time, emotions and their corresponding bodily change(s) become associated with particular situations and their past outcomes.
When making decisions in the future, these physiological signals (or ‘somatic markers’) and its evoked emotion are consciously or unconsciously associated with their past outcomes and bias decision-making towards certain behaviors while avoiding others. For instance, when a somatic marker associated with a positive outcome is perceived, the person may feel happy and motivate the individual to pursue that behavior. When a somatic marker associated with the negative outcome is perceived, the person may feel sad and act as an internal alarm to warn the individual to avoid a course of action. These situation-specific somatic states based on, and reinforced by, past experiences help to guide behavior in favor of more advantageous choices and therefore are adaptive.