Say you’re visiting your friend, who lives in a city. You’ve found some street parking a few blocks away, had a few drinks, and now you’ve settled into bed. Suddenly, your eyes snap open. Did you lock your car? You always lock your car when you close the door, so you probably did lock it. But you’re not going to get to sleep unless you wake your friend up, ask him for the keys so you can get back into the apartment, trudge a couple of blocks down, and click the button on your fob until you hear that reassuring beep. You might go to the car and give the handle a few tugs for good measure, just to be sure. Finally, you can settle back into sleep, but you’re tortured by dreams of somebody breaking into and stealing your car despite all this.
While some might have rested easy knowing that they have never left their car unlocked, in this hypothetical scene, you’re a highly neurotic individual. Neuroticism is one of the Big Five personality traits, and it’s characterized by an extreme sensitivity to negative stimuli (in this scenario, the imagined stimuli of having your car broken into).
Compared to the other Big Five personality traits — openness, conscientiousness, extraversion, and agreeableness — it’s easily the crummiest of the lot. Individuals high in neuroticism are prone to anxiety and worrying, anger and fear, depression, jealousy, loneliness, and pretty much every other unpleasant state of mind. As a logical consequence of all this stress, they tend to suffer from poorer mental and physical health.
Which begs the question: Why does the human personality even allow for neuroticism? Is it a mistake, the result of some genetic fluke that supercharges your wires with anxiety? Some researchers say no; neuroticism may have played an important role in our species’ ancient past.
Surviving and thriving through constant worrying
In the general population, neuroticism follows the normal distribution, meaning most people converge on a typical degree of neuroticism, with individuals scoring high or low in neuroticism becoming increasingly rarer and rarer as their scores grow more extreme. Coupled with the fact that a significant chunk of neuroticism is inherited, there is likely some evolutionary benefit to being a little neurotic.
In the environment that we evolved in, the consequences of being harmed were dire — breaking a leg from a fall, having a meal stolen by another animal, or being attacked by a predator would often result in death, and, as a consequence, the end of your genetic line. Neurotic individuals tend to interpret ambiguous stimuli as dangerous and react more quickly and strongly to negative stimuli, which would make them less likely to expose themselves to dangerous environments or to take risks. Although the modern world is fairly safe, we can still see this mechanism at play; individuals who partake in extreme and dangerous activities like, say, climbing Mount Everest, tend to score unusually low in neuroticism.
The same mechanism applies to social interaction as well. Human beings are highly social animals, and one of the hallmarks of neuroticism is self-consciousness and shyness, traits which at first blush don’t seem beneficial to a social life. Today, they certainly aren’t, but in our past, a highly neurotic individual wouldn’t be likely to cause any major waves in their group and would be very wary of engaging in a negative social interaction. Thus, ostracization would be less of a threat, and, with the support of their group, they would live longer, providing them with more chances to reproduce.
Admittedly, highly neurotic individuals are less likely to make close relationships with others. Not only that, but the personality trait is also associated with poorer mental and physical health, characteristics which would suggest that lower neuroticism should be selected for instead.
The downsides to neuroticism are well known, but there are actually some benefits to neuroticism beyond just avoiding danger. Individuals who score highly on neuroticism tend to be more competitive and to attain more academic success than their less worry-prone peers. The reason, ostensibly, is that these individuals are driven to escape negative conditions (such as poverty), driving them to achieve greater status. Furthermore, personality is a complicated thing, and many of the most negative aspects of high neuroticism can be mitigated by other factors. Some researchers speculate that traits such as high intelligence, impulse control, conscientiousness, and others may reduce neuroticism’s downsides while enhancing its upsides.
A neurotic sweet spot
Thus, it may be the case that our environment selected for a Goldilocks-level of neuroticism. Those who were overly neurotic would be at greater risk for depression, anxiety, and all the other poor mental and physical health outcomes associated with neuroticism, making them less likely to succeed and reproduce. Those with low neuroticism would needlessly expose themselves to danger and starve, get injured, or get eaten before they could reproduce. Those with just the right amount of neuroticism would avoid threats, work hard to avoid negative status, maintain their mental and physical well-being, and maximize their chance at propagating their genome.
Of course, the same selection pressures don’t apply to us today, and any highly neurotic individual is likely to curse their fearful ancestors for making themselves so damn nervous all the time. Luckily, studies have shown that neuroticism can be reduced to some degree through therapy, and mindfulness meditation has been shown to have the largest impact in terms of reducing anxiety and depression in individuals who score highly for neuroticism.
There’s also the fact that even today, outside of the wild environment in which we first evolved, there are benefits to being a little neurotic. Highly creative individuals tend to be more neurotic, and individuals who score highly for both neuroticism and conscientiousness tend to channel their anxiety into healthy behaviors, such as going to the gym or working more diligently. So, the next time you find yourself awake at night worrying about some mundane detail, just remember that it’s thanks to that worry that your ancestor didn’t get eaten by a jaguar.
This article was originally published on Big Think.
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