Fred Carstensen writes:"Perhaps we ought to ban 'rationality' from the vocabulary of economics; it misleads because it implies something that it does not." This reminds me of Joseph Schumpeter's and F.A. Hayek's call for banning the term "capital" from "scientific usage" because they had trouble with its usage in the classical tradition to mean "funds" accumulated out of savings -- in the theory of interest. It may well be that psychologists use the term rationality differently from economists, the former meaning reasonableness of behavior. But economists use the term rationality to mean purposive behavior. Thus, as Robert Leeson has explained, the suicide bomber acts rationally, i.e., purposively -- maximizing a different sort of utility function than most other people. The failure to apply the economic meaning of rationality often leads to bad or poor analysis of other people's behavior (choices). Gunnar Myrdal, for example, argued against the applicability of "Western" economics to people of the Third World because it employs utility maximization or rational choice. This because from his travels in Asia, he found some starving Hindus who wouldn't eat a cow to stave off death. But a Hindu, who believes s/he has a soul and which would suffer eternal damnation from eating cow meat, is acting rationally: to enjoy eternal salvation. What a poor trade it would be to extend one's life for perhaps two more weeks or even a year at the expense of eternal suffering of the soul -- according to the individual's belief? When we start off from the premise that people act rationally -- purposively, not reasonably from our own points of view -- we are more inclined to study or try to understand why they do what they do. (Doug Mackenzie's post on this is quite helpful.) We are then in a better position to offer alternatives to them so they might change their life's choices, aka, behavior, rather than impose our preferences on them. The latter attitude is what leads to dictatorships. On this issue I am very much instructed by Alfred Marshall's (Principles, Bk 1, Ch. 2) explanation of what economics is about. I might also add that Ayllon and Azrin (1965) found rational behavior -- consistency of choice -- among patients in a mental asylum, which they published in the Journal of Experimental Analysis of Behavior. I have difficulty believing that some economists have a problem with rationality in economic analysis. James Ahiakpor