have shown that people who display an implicit bias have a stronger electrical response to black or other-race faces in an area of the brain known as the amygdala—a structure responsible for processing emotional stimuli and eliciting a fearful or
anxious mental state. An exaggerated amygdala response is part of what creates the sudden visceral or “gut feeling” of being scared. And that feeling of fear has additional psychological effects that
promote prejudice. It is well-established that when one feels their welfare is being threatened, they tend to become more tribal in their behavior, and additionally bolster their cultural or national worldviews, since it is those worldviews that make them feel safe. In essence, nationalism and
prejudice are knee-jerk responses to anxiety.
Fortunately, that isn’t the whole neuroscience story. In people with healthy functioning brains, the fast amygdala response activates a region of the brain known as the prefrontal cortex, which is slower and plays a regulatory role. When the fear system is triggered, prefrontral areas work to assess the situation rationally, and calm the pesky automatic system. Thanks to specific regions like the dorsolateral prefrontal cortex, and the anterior cingulate cortex, the brain exercises cognitive control, suppressing inappropriate or prejudice judgments and behavior.
The problem is, not everyone has a healthy functioning prefrontal cortex, and these people are the ones whose biases control them. They cannot reason those fearful surges away because they lack the cognitive mechanisms that normally allow people to do so.