Better than rational: Evolutionary psychology and the invisible hand

Several years ago, we attended an interdisciplinary seminar on what were purported to be biases in negotiation behavior. The economists, psychologists, and biologists present were mulling over the data when, suddenly, a prominent economist lit up. Ah, I see,' he said, is either or it's psychological. This formulation stuck in our minds, because it seemed to succinctly give voice to a tacit assumption held by many economists one that we think works to the detriment of economics, by isolating it from the relevant parts of biology, psychology, and the rest of the natural sciences. This assumption is that behavior is the state of nature, requiring no explanation. Explanations that invoke the cognitive processes…