Brain imaging studies have been painting an overly-simplistic picture of the how the brain works. It has even filtered into TV programming. In one episode of a popular legal drama, a character claimed to have figured out that a policeman was racist because his amygdala activated whenever he was shown pictures of black people, demonstrating his fear of them.
This simplified picture troubles many cognitive researchers, including William A. Cunningham of Ohio State University. It's true that the amygdala becomes increasingly active when people are afraid, but that's far from the whole story. The amygdala plays a much broader role in the brain's functioning than merely responding to fear.
To portray a single area of the brain as the locus of any one emotion is a vast oversimplification.
A recently published article co-authored by Dr. Cunningham reviews the published literature on the function of the amygdala. The article concludes that a major function of the amygdala is to process events that are of immediate concern to a person. Being in a scary situation is certainly an immediate concern. But so is food to a hungry person. And hungry people show increased amygdala activity when they're shown pictures of food. So do people with a high degree of empathy when they're shown pictures of other people in distress.
This is just one example of a deeper issue. People studying the brain want to find brain regions that are responsible for specific emotions. Many imaging studies, particularly fMRI (functional magnetic resonance imaging) studies, appear to show just that, finding increased or decreased activity of a brain region when people are feeling a particular emotion. But the brain isn't wired so simply, so the conclusions that can be drawn from such findings are not as cut and dried as we might like to think.
Most brain functions require extensive coordination between several different regions of the brain networking. Emotions are no exception to this rule and seem to be distributed over the entire brain. Whatever emotion you may be feeling, it's likely that many different parts of the brain are involved. To portray a single area of the brain as the locus of any one emotion is a vast oversimplification.
The amygdala is certainly involved in the fear response. But it's unlikely to be the only part of the brain that's involved.
A 2009 article discussing common errors in fMRI studies that was also co-authored by Dr. Cunningham concludes: "We recommend placing a greater emphasis on replication and meta-analysis to determine which effects are real, and less emphasis on trying to determine the final truth from individual studies."
Dr. Cunningham's article on the amygdala appears in Current Directions in Psychological Science.
Wil Cunningham, Ph.D. is an assistant professor in the Department of Psychology at Ohio State University and an Associate Scientist at the Rotman Research Institute, Baycrest Hospital, Toronto.