Most texts mention at the outset that our rational choice model takes people's tastes as given. But having said that, most texts then proceed to ignore all motives other than material self-interest. It is easy to see why, because economic research has scored its most impressive gains on the strength of this portrayal of human motivation. It tells us, for example, why car pools form in the wake of gasoline price increases and why thermostats are generally set lower in apartments that have separately metered utilities. And yet, as students are keenly aware, our homo economicus caricature is patently at odds with much of what we know about human behavior.
People vote in presidential elections.
They give anonymously to public television stations and private charities. They donate bone marrow to strangers with leukemia. They endure great trouble and expense to see justice done, even when it will not undo the original injury. At great risk to themselves, they pull people from burning buildings and jump into icy rivers to rescue people who are about to drown. Soldiers throw their bodies atop live grenades to save their comrades.