Cognitive scientists recognize two types of rationality: instrumental and epistemic. A simple definition of rationality is behaving in the world so that you get exactly what you most want, given the resources (physical and mental) available to you. The other aspect of rationality studied by cognitive scientists is termed epistemic rationality. This aspect of rationality concerns how well beliefs are corroborated by actual evidence. Instrumental and epistemic rationality are related.
Does emotion thwart rationality? The claim that emotion inhibits rationality is not consistent with definition of rationality in modern cognitive science. Instrumental rationality is behavior consistent with maximizing goal attainment. There is no specific psychological process at work here. Emotions may enhance instrumental rationality, or they may impede it. Emotions provide an approximation of the correct response. If more accuracy than that is required, then a more precise type of analytic cognition will be required (Stanovich, 2009) It is possible to rely too much on the emotions. We can base responses on an approximation when what is really needed is a more precise type of analytic thought. More often than not, processes of emotional regulation enhance rational thinking and behavior.
Neurology of decision making
People with damage to an area in the prefrontal cortex, the ventromedial area, are often irrational. This is because their processes of emotional regulation are deficient (integration of cognition and emotion). Emotion is one of many tools of rational thought.
An emotion may be defined as a collection of changes in the brain and other parts of the body triggered by a dedicated brain system that responds to one’s perceptions. (Damasio 1994, 1999, 2003, 2005). These changes range from modification of the internal environment and viscera that may not be perceived by an observer (e.g., endocrine activity, heart rate, micro-sweating) to changes in the musculoskeletal system that may be obvious to an observer (e.g., posture, facial expression, specific behaviors such freezing, aggression, voice variation and so on). Humans have different types of emotional experiences.
In the past 25 years, Damasio and colleagues have studied several patients with lesions of the ventromedial prefrontal (VM) cortex who showed impairments in judgment and decision-making. The case of Phineas Gage spearheaded the way for the idea that the frontal lobes were associated with judgments, decision-making, social interactions, and personality. There are reports of numerous cases of people with frontal lobe damage that show defects similar to those of Phineas Gage. (As cited from Damasio, 2005- Brickner, 1932; Welt, 1888 ).
“Patients with bilateral damage to the VM prefrontal cortex develop severe impairments in personal and social decision-making” (Damasio, 2005, p.337) . They have difficulties planning their day, as well as difficulties in various types of social activities. They do not learn from previous mistakes as reflected by perseveration of decisions that lead to negative consequences.
VM patients generally produce average scores on general neuropsychological tests, however, they have a decreased ability to express emotion and experience feelings in appropriate situations. To reiterate, they demonstrate abnormalities in decision-making. Emotions are key factors involved in the interaction between environmental conditions and decision making.
“The process of deciding advantageously is not just logical but also emotional” (Damasio, 2005, p. 368)