Personality traits that are not advantageous in some way are unlikely to be maintained over many generations of evolution.
Personality traits that are universally advantageous would not be discernible as traits, because they would become universal to everyone.
Therefore, all personality traits must also be disadvantageous in some way.
So-called "dark trait" behaviors obviously confer advantages at least in the short term. In the long run, we're all dead, but early success compounds, like interest.
Some of the luckiest psychopaths will end up at the very top, while some of the unluckiest will end up six feet under.
This is difficult to accurately capture in statistics, but the expected gain from "dark triad" traits across the whole population is probably zero.
Some personality traits haven't adapted to modern life as well as others and some have adapted extremely well. For instance most people have too much anxiety since you had to be way more careful throughout history. Now you have so much safety net everywhere so risk taking is a much more valuable trait as most people are biased against taking risks.
It is not true that traits that are not advantageous are unlikely to be maintained over many generations. For example, many genetic diseases have survived for many generations. This may happen because, for example, they correlate with some other more positive traits. Or, because of other indirect, external factors.
Great comment! High risk, high reward behavior, almost by definition, doesn't often seem too appealing when looking at the averages. We aren't the only organism that loves to gamble though, and there's a reason for that.
Personality traits that are universally advantageous would not be discernible as traits, because they would become universal to everyone.
Therefore, all personality traits must also be disadvantageous in some way.
So-called "dark trait" behaviors obviously confer advantages at least in the short term. In the long run, we're all dead, but early success compounds, like interest.
Some of the luckiest psychopaths will end up at the very top, while some of the unluckiest will end up six feet under.
This is difficult to accurately capture in statistics, but the expected gain from "dark triad" traits across the whole population is probably zero.