Neurons in the frontal lobe may be responsible for rational decision-making

You study the menu at a restaurant and decide to order the steak rather than the salmon. But when the waiter tells you about the lobster special, you decide lobster trumps steak. Without reconsidering the salmon, you place your order—all because of a trait called “transitivity.”

“Transitivity is the hallmark of rational economic choice,” says Camillo Padoa-Schioppa, a postdoctoral researcher in HMS Professor of Neurobiology John Assad’s lab. According to transitivity, if you prefer A to B and B to C, then you ought to prefer A to C. Or, if you prefer lobster to steak, and steak to salmon, then you will prefer lobster to salmon.

“People make choices by assigning values to different options. If the values are menu invariant preferences will be transitive. The activity of these neurons does not vary with the menu options, suggesting that these neurons could be responsible for transitivity,” Padoa-Schioppa explains.