Promises, Promises: A Specific Neural Signature in Dishonesty

Making and keeping promises form the basis of human cooperation and trust and likely underlie more-complex social and legal contracts and institutions. In an elegantly designed study, researchers used functional MRI to examine the neural circuitry underlying the acts of keeping and breaking promises in 34 healthy male students.

In an economic trust game, a “trustee” first decided how strongly to promise to share money with an “investor,” then waited while the investor learned of the promise and decided whether to trust him (and give him the money), and finally either kept the promise and shared the money, or broke it and retained the money. A similar game that lacked the promise stage controlled for both fairness and differences in material …