The Neuroscience of Fear: What Happens in Your Brain When You're Afraid

What happens in our brain when we are afraid? Plus, is fear innate or learned?

Sabrina Stierwalt, PhD
5-minute read
Episode #212

I love horror movies – whether it be ghosts or monsters, gore or suspense – but I have plenty of friends who would rather do just about anything else than watch a masked man with a chainsaw. What is it that draws some people towards activities meant to scare, like horror movies or haunted houses, but makes others run screaming?

What happens in our brain when we are afraid?

Our response to scary situations is often described as our “flight-or-fight” response. In a scary situation, our body can produce adrenaline (which can lead to great feats of strength otherwise not possible under tamer circumstances) and groups of hormones called endorphins (also linked to exercise and positive mood enhancement).

A 2008 study in the Journal of Neurology also found that flooding the brain with dopamine is also linked to behaviors suggestive of fear and paranoia in rats. Since dopamine is also associated with pleasure, its release in scary situations, along with a so-called “rush” of adrenaline and endorphins can lead to an elevated mood or high. Some people enjoy this high more than others.

Most people do not actually want to live through a terrifying or traumatizing ordeal. The key difference with experiences like scary movies, haunted houses, and even roller coasters is that our brain can quickly process the threat and determine that it is not “real.” So if our senses trigger a fear response, for example if we suddenly feel the floor drop out from under us on an amusement park ride, our brain can immediately recognize that we are not in any real danger but are instead in a safe, controlled environment.

Although psychologists have not identified a “fear center” in the brain, the amygdala, nestled between the temporal lobes, appears to be involved in how we process scary situations or threats. Animals with amygdala damage are observed to be tamer and have less of a flight-or-fight response. Neural activity is also observed in the human amygdala, along with increased heart rate, when threats are introduced. Evidence for the dominant role in fear response played by the amygdala was further found in a 1995 study in the Journal of Neuroscience of a woman known as “SM” with a rare genetic disorder, Urbach-Wiethe disease, which caused her amygdala to harden and shrink. Not only could “SM” not recognize fearful expressions, she also showed no signs of fear in typically scary situations like haunted houses or when surrounded by venomous snakes.

See Also: Why Do We Like to Be Scared?

Is fear innate or learned?

Some fears are innate, like the fear that tells you not to jump off that platform, even though you know you are safely tied to a bungee cord that will keep you from hitting the ground. We depend on these fears for our survival. However, we can also be conditioned to fear things that otherwise would not be scary.


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About the Author

Sabrina Stierwalt, PhD

Dr Sabrina Stierwalt earned a Ph.D. in Astronomy & Astrophysics from Cornell University and is now a Professor of Physics at Occidental College.