"The "rationality" described by rational choice theory is different from the colloquial and most philosophical uses of the word. For most people, "rationality" means "sane," "in a thoughtful clear-headed manner," or knowing and doing what's healthy in the long term. Rational choice theory uses a specific and narrower definition of "rationality" simply to mean that an individual acts as if balancing costs against benefits to arrive at action that maximizes personal advantage. For example, this may involve kissing someone, cheating on a test, buying a new dress, or committing murder. In rational choice theory, all decisions, crazy or sane, are postulated as mimicking such a "rational" [balancing costs against benefits] process.
The practitioners of strict rational choice theory never investigate the origins, nature, or validity of human motivations (why we want what we want) but instead restrict themselves to examining the expression of given and inexplicable wants in specific social or economic environments. That is, they do not examine the biological, psychological, and sociological roots that make people see the benefits encouraging them to kiss another, cheat on a test, use cocaine, or murder someone. Instead, all that is relevant are the costs of doing so—which for crimes, reflects the chance of being caught.
In rational choice theory, these costs are only extrinsic or external to the individual rather than being intrinsic or internal. That is, strict rational choice theory would not see a criminal's self-punishment by inner feelings of remorse, guilt, or shame as relevant to determining the costs of committing a crime. In general, rational choice theory does not address the role of an individual's sense of morals or ethics in decision-making. Thus, economics Nobelist Amartya Sen sees the model of people who follow rational choice model as "rational fools."
Because rational choice theory lacks understanding of consumer motivation, some economists restrict its use to understanding business behavior where goals are usually very clear. As Armen Alchian points out, competition in the market encourages businesses to maximize profits (in order to survive). Because that goal is significantly less vacuous than "maximizing utility" and the like, rational choice theory is apt."