Oh my god, is that like Billy? Your heart skips a beat, your face starts to turn red, and you quickly pull out your phone to mask that you’ve seen him. Oh wait, I guess that’s just someone else with a black back pack. Never mind. The reason for such an intense physical reaction to this situation, and many other behaviors that seem to have no actual purpose in today’s society are discussed in a recent Slate article by Rob Dunn.
Though today we live in a relatively peaceful time, where the human species is clearly the dominant one, this was not always the case. In the Environment of Evolutionary Adaption (EEA), our ancestors the Homo Sapiens faced the very real danger of becoming the prey of another animal. We were hunted by a variety of species including: cats, eagles, snakes, wolves, lions, tigers, bears (oh my!), and possible even giant, predatory kangaroos. It is postulated that the reason that we were such a popular snack was that our hairlessness made us easier to digest.
Those who developed traits that allowed them to avoid being eaten were the ones that survived and reproduced, causing these traits to be selected for over time. One of the main mechanisms that we developed involves our sympathetic nervous system, or a fight-or-flight response. This system causes us to react quickly to any sight or sound that signals danger (or possible predation). As soon as we hear a twig break or movement in our peripheral vision that seems threatening our heart speeds up, we have increased blood flow to our muscles, and increased air to the lungs. All of these things are meant to allow you the ability to either stay and fight, or run, effectively.
Today, we have solved the constant danger of predation by moving into houses and cities, and by virtue of our ancestors causing many of the most dangerous predators. Evolution is an extraordinarily slow process, though, thus we still experience this jumpiness in our daily lives. It seems unreasonable for us to have this same intense fight-or-flight reaction when we see Billy, think we may be late, or feel like we may be reprimanded at work. These are simply remnants of our previous danger of predation, but they are causing serious problems for people today (hence the large market for pills like Valium and Xanax).
Anxiety is not the only issue that we as humans have today that was adaptive during the EEA. Dunn goes on to describe the different ways that interactions of our ancestors with parasites, pathogens, and possible even fruits have caused us to adapt in certain ways that may no longer be beneficial. It has become generally accepted in the field of psychology that our bodies are not ideal for the environment that we currently live in, and that this is the reason for many of our current pathologies. This evolutionary lens then becomes important to understanding many of the problems we have today – anxiety, depression, prejudice – all of which have been linked to adaptations in the EEA. Evolution has not stopped, though, and though it moves slowly in comparison to how rapidly our world has shifted from small groups of hunter-gatherers to large cities and a global mindset, it will continue to interact with the way that we adaptively (or maladaptively) interact with our environment.