If you had to list the things that scare you the most, what would your list include? Human fears run the gamutt, from the insignificant (spiders and heights) to those that haunt us in the wee hours of the night (loss of a loved one, inevitable death). Fear, like other emotions, is a visceral aspect of humanity. But it goes even deeper than that, for fear transcends the boundaries of humanness. It’s part of our evolutionary heritage.
Want to scare a chimp? Place a plastic snake next to an unsuspecting primate (humans included) and you’ll probably witness pure, unadulterated fear. That’s because the fear of snakes appears to be hardwired into many primate brains; a deep-seated phobia that may have evolved to keep us safe. Since many snakes possess the ability to kill, it seems only logical that animals that avoid a close encounter might have an evolutionary edge over the less cautious.
But where does fear reside? And what actually happens when we are scared? Like any emotion, it all begins in the brain.
Many parts of the brain are activated during the fear response. And the majority of them are located deep within; a testament to their ancient origins. Yes, our fancy cortex also plays a role in fear, but the rest of the hardware we share with other animals, since critters lacking fear would stand little chance of surviving in our dangerous world.
Here’s a quick glimpse at the brainy bits responsible for processing fear.
Our sensory cortexes interpret what we see, hear, smell, and feel. The information is whisked to the thalamus, which decides where to shuttle the data, and the hippocampus then places the data in context. The amygdala decodes the data and determines if a threat exists. And if the threat is real, the hypothalamus activates the fight or flight response, which kicks the body into high gear to respond to the situation.
Of course, these reactions happen with lightning speed and, in many cases, the body simply responds as if threatened, even if the threat turns out to be benign. It’s better to gear up than to sit back and contemplate. A momentary hesitation could spell death.
The hypothalamus activates two separate systems when it launches the “fight or flight” response. The sympathetic nervous system activates stress hormones, adrenaline and noradrenaline, which are dumped into the bloodstream. As they circulate, they increase heart rate and blood pressure, which explains the thumping in your chest that accompanies a scary jolt. At the same time, the pituitary gland gets involved by secreting a hormonal cascade that primes the body for action. Pupils dilate (to improve visual acuity), blood vessels in the skin constrict (to shunt blood to the major muscles), and muscles tense for action (which explains the goose bumps). While the essential functions are enhanced, nonessentials, such as digestion and immunity are sidelined. That way, the body can focus on the immediate threat and conserve energy in the process.
But if fear evolved to improve survival, why is it so many of us love a good scare? I admit, I’m an adrenaline junkie, much of which I blame on the years I spent as a firefighter. Once you’ve rushed headlong into a burning building, daily life can seem a bit monotonous, which probably explains my love of rollercoasters, skydiving, and scary movies.
But the reason many of us love a good scare is because the fight-or-flight response involves many neurotransmitters, namely endorphins, dopamine, and serotonin, that are also responsible for a rush of pleasure (think orgasms). That is why a momentary scare is followed by a blissful blast of relief. Once our brain realizes the fear isn’t real, our body can simply enjoy the rush, which is why screaming is often trailed by nervous giggles.
But humans can do something no other animals can: they can conjure fear. Our sophisticated brains enable us to do some amazing things. But they also come at a price, for although we are gifted with imagination, much of our imagining can evoke fear.
Fear of the future, fear of loss, fear for the ones we love… there are a million ways we torment ourselves by conjuring fear. But it is worth noting that, however much we languish in fear, it has little effect on outcome.
So keep your fear in check and save it for life’s true emergencies. The next one could be right around the corner…