A new study has said that the link between amygdala and fear, especially a fear of others unlike us, has gone too far not only in pop culture but also in psychological science.
The amygdala are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotional reactions, the amygdalae are considered part of the limbic system.
Many experiments have found that the amygdala is active when people are afraid. But it also activates at other times, for example in response to pleasant photographs and happy faces.
The misconception came from how scientists first approached studying the brain. A lot of people came to the amygdala from the study of fear, says Wil Cunningham of Ohio State University, who co-wrote the new paper with Tobias Brosch of New York University.
"It's a great emotion to study because it's very important, evolutionarily, and we know a lot about fear in animals," Cunningham said.
Almost every study of fear finds that the amygdala is active. But that doesn't mean every spark of activity in the amygdala means the person is afraid.
Instead, the amygdala seems to be doing something more subtle - processing events that are related to what a person cares about at the moment.
"When we're studying emotion, people want to find specific brain parts that are associated with different emotions," Cunningham said.
Especially in the early days of neuroscience, scientists hoped that soon it would be possible to use MRI and other brain-imaging techniques "to get under the hood and find out what people are really thinking."
A lot of the time, people really don't know, or won't say, what they're thinking, and it would be nice to be able to look at a picture of their brain and know the answer. But the brain is too complicated for that. Cunningham also thinks many scientists have gotten too attached to a rigid definition of emotions-anger, fear, sadness, happiness, and so on.
However you may feel, it seems that many different parts of the brain are involved.
"Emotion is going to be distributed across the brain," he added.
The study will be published Current Directions in Psychological Science.