8 Ways Evolution Has Made You Terrified Of Everything

6. OCD: Disease

In basic terms OCD manifests as an obsessive need for order and often a pathological phobia of dirt, but this debilitating disorder probably began life as an evolutionary advantage. Instincts for disgust essentially protect us from disease, it is the forerunner for what we now call hygiene. One of the reasons why humans have managed to proliferate across the planet so successfully is because, thanks to our knowledge of hygiene, fewer of us drop dead from minor flesh wounds, fewer of us contract deadly diseases and fewer of us offer joy-rides to dangerous parasites. The need for extreme control that often manifests in OCD makes way more sense if you plonk the sufferer out in the wild. Out there, it most certainly behooves you to keep your eye on the ball and to try to exercise as much control as possible over a completely unpredictable environment. The inability to shut off to external threat in the world that goes along with OCD is actually a pretty solid survival instinct, albeit one that has morphed, changed and perhaps even been exacerbated by modern times.