While it's been said humans have nothing to fear but fear itself, it turns out there are a lot of things in our DNA that dictate what we fear. Why are certain things scary? Some things are scary because they bring us back to negative memories, while others are scary because of the physical response they illicit in our bodies. And while some phobias are downright weird, there are lots of things that are instinctively scary to humans, and for good reason. Fear is a pivotal component to everyday survival, engrained in us from our long lost ancestors. Some of these fears turn to full-blown phobias.
But there's no denying there are universally scary things in nature. Some scientists have suggested fears are passed down through DNA, meaning there are certain things we are born to fear.
Public speaking isn't just a fear of awkward high schoolers - it's a universal fear felt by people worldwide. Even people who aren't terrified of public speaking get some of the symptoms associated with the fear: butterflies in the stomach, sweating, have trouble sleeping the night before. And that's because the root of this fear is built into our DNA.
This fear comes from our amygdala - the part of our brain that regulates emotion - reacting to the emotions displayed on each and every face in the audience, picking them apart to see which, if any, people pose a genuine threat. Specific configurations of facial features can be interpreted as threatening on a primitive level. The end result is crippling stage fright that most of us have been through at some point in our lives. Our instinct when faced with a sea of faces - especially if they're unfamiliar ones - is not to continue with the presentation, but rather to win what our mind has interpreted as a staring contest. That's why some people, when faced with the reality of public speaking, simply stare blankly into the crowd. For this reason, many people will picture something bizarre, like picturing the audience in their underwear, to overcome their glossophobia.
Sudden Movements, Sounds, Or Surprises
As it turns out, you can actually be scared to death. That's because humans are hardwired to have physical reactions to being scared by sudden movements, sounds, or surprises. When we're in a normal, undisturbed state, our body is at rest, so to speak. When something occurs - a noise, someone suddenly coming into a room, feeling your surroundings move unexpectedly - it triggers our startle reflex, something we've developed as a means of survival.
This is an intense chemical reaction where adrenaline floods the body and your brain, causing a reaction. Some people love this feeling, which is why haunted houses are so popular. But some people are unable to stop the adrenaline from flowing and are left with a full-blown panic attack.
Typically, claustrophobia - or the fear of small spaces - is considered a learned phobia. But researchers are beginning to believe this fear could come from our ancestors. Whenever a human is faced with an obstacle or high-stress situation, the natural evolutionary response is known as fight or flight. This is triggered in the adrenal medulla, which sends hormones to the rest of our body that tell us to either leave the situation quickly or fight it. Claustrophobes experience anxiety in small spaces, turning on the fight or flight response. And those who are not able to quell their fear are thrown into a full-blown physical response to the fear.
Some scientists believe avoiding small spaces is an instinctual survival mechanism, and those who experience the fight or flight response in small spaces are reacting to a dormant evolutionary means of survival.
A lot of people fear blood. Some people don't fear blood, but get queasy when they see it or have it taken from them. Why is that? Science seems to suggest that people who faint or get dizzy at the sight of blood are reacting to an evolutionary fear reflex.
When some people blood, the vagus nerve that runs from the human head to the heart is triggered. It sends a signal - called a vasovagal scope - to the heart that tells it to slow down, which reduces the bloodflow to the brain. This signal happens for a lot of reasons - not eating enough, low blood sugar, lack of sleep. But why does it happen when people see blood?
From an evolutionary standpoint, visible blood typically means someone is hurt. In our hunter-and-gatherer days, this was probably a result of an animal attack. To avoid being killed by an animal (or by another human) our body shuts down and "plays dead." The vasovagal scope kicks in, telling our heart to slow down and play dead, causing us to faint. The more a person sees blood, however, the less this response kicks in, which is why doctors and nurses can stomach the sight of blood better than, say, a little kid.