The Vulcanization of the Human Brain: A Neural Perspective on Interactions Between Cognition and Emotion

E motions influence our decisions. They do so in just about every walk of our lives, whether we are aware or unaware of it and whether we acknowledge it or not. In particular, I will argue that emotions may explain inconsistencies in human behavior and forms of behavior that some have deemed irrational, though such behavior may seem more sensible after a discussion of the functions that emotions serve—or may have once served in our evolutionary past. People do have the capacity to override emotional responses. This capacity relies in large measure on the most recently evolved parts of our brains that support forms of behavior that are more recognizably rational. Neuroscientists are beginning to make headway in identifying the neural mechanisms involved in both emotional responses and higher cognitive processes. This effort offers the promise of a deeper understanding of how and why emotions impact decision making, how this may contribute to behavior that appears to deviate from optimality, and how and when we are able to overcome such emotional responses. In this article I will review a series of human brain imaging studies of decisionmaking behavior. I will argue that the human brain is best understood as a confederation of mechanisms that usually act together, but at times may come into competition with one another, favoring different evaluations of similar circumstances. Modern brain imaging methods allow us to measure this competition and relate it to behavioral outcomes. I will describe examples of these processes, drawn from different domains of psychological function. These examples provide evidence that competition among different brain mechanisms can provide insight into the seemingly inconsistent or irrational responses that are of such interest to behavioral scientists. In particular, I will entertain the idea that a broad range of