Haunting Hormones: The Science of Fear!


Oh, Halloween. An entire holiday dedicated to the (particularly unpleasant) emotion induced by the threat of danger, pain, harm, or watching the movie It. Yes, we are talking about fear.


(Source: Pyscho (film))

We’ve known that people develop specific fears as a result of learning since 1920, back then when ethics in science weren’t really a thing and Mr. John B. Watson made little Albert -an eight month old baby- deathly afraid of white, furry objects (including but not being limited to rats, rabbits, dogs, and balls of cotton) by making a loud noise every time he touched one. We are, in essence, conditioned to fear certain things because we learn to associate them with pain and danger.

That’s the Psychology side of it. But what about Neuroscience? A hypothesis that has been around for a while is that the amygdala, a little nugget in the middle of our brain, is the home of scary feelings. Professor Joseph E. LeDoux from New York University (also lead singer and songwriter of rock band The Amygdaloids) has been studying it for over 30 years and is now trying to debunk the idea that the amygdala is the brain’s fear center.

This interpretation came about because we found that when the amygdala is damaged, previously terrifying things start to be treated as benign. For example, snakes no longer attack potential threats after amygdala damage. The same is true of humans: when exposed to danger, activity in the amygdala increases. The amygdala is part of a neural system that detects and responds to threats. Knowing this, concluding that the amygdala produces feelings of “fear” seemed like a fairly logical jump.

However, while people with amygdala damage do respond less violently to threats, they can still feel afraid and amygdala activity does not necessarily mean that fear is experienced, as it is also active while eating, drinking, and having sex, none of which sounds particularly frightening. The conclusion that the amygdala is the brain’s fear center wrongly assumes that the feeling of “fear” and how we respond to it both come from the same place. Professor LeDoux’s research seems to only suggest the latter. Remember, correlation does not imply causation (or if you want to sound fancy, post hoc ergo propter hoc).

In fact, his research suggests that the amygdala contributes only to non-conscious aspects of fear, such as detecting threats and controlling automatic body responses that help us cope. The amygdala’s contribution is therefore a lot more mundane than people think: it detects threats and alters how our brain processes information, leading to secretion of chemicals in the brain (like norepinephrine, acetylcholine, dopamine, and serotonin) and hormones like adrenalin and cortisol, which make us more alert and able to better respond to threats. He hypothesizes that the brain then processes all of these experiences and assembles the conscious experience we know as fear. However, the role of the amygdala is limited to automatic, unconscious body responses.

Why do we feel fear? It’s not precisely what one would call an enjoyable emotion. Actually, fear is a natural response that helped keep our ancestors alive. All those chemicals and hormones create a “fight-or-flight” response: increased heart rate, sweat and faster breathing get the body ready to exert itself while escaping or defending itself. Furthermore, the feeling of fear makes us want to stay far, far away from dangerous things. Both of those things probably came in handy back when we had to fight wild animals for food and territory.

This natural high, however, is also why some people utterly adore scary movies. Professor Glenn Sparks from Purdue University explains that it has a lot to do with our brain chemistry: one of the main hormones released is dopamine, a hormone related to pleasure and rewards. Some people get more of a kick from it than others, the kind of people who also love rollercoasters, because they have fewer enzymes that help break down the dopamine and neutralize its effect. Furthermore, this is also related to the amygdala: we enjoy scary movies and haunted houses because of the flood of adrenaline, endorphins, and dopamine, but in a completely safe space. While they startle us by triggering our senses and thus generating a non-conscious response from the amygdala, our brain also has time to process the fact that they are not “real” threats and can thus reduce the feeling of fear.

Overall, you should always be suspicious of any statement that claims a single area of the brain is wholly responsible for some function, that way of thinking is a relic from a time when what we knew about brains was based on the effect of brain lesions. Nowadays, we think of functions as products of a system.

Have a very dopamine-filled (be it scary, happy, or both) Halloween!

#LuciaArce #Halloween #Fear #Biology

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