The evolution of narcissism

Christine Dell'Amore explains the value of routine overestimation:

Some experts have suggested that overconfidence can be a good thing, perhaps by boosting ambition, resolve, and other traits, creating self-fulfilling prophecies. But positive self-delusion can also lead to faulty assessments, unrealistic expectations, and hazardous decisions, according to the study—making it a mystery why overconfidence remains a key human trait despite thousands of years of natural selection, which typically weeds out harmful traits over generations.

Now, new computer simulations show that a false sense of optimism, whether when deciding to go to war or investing in a new stock, can often improve your chances of winning. "There hasn't been a good explanation for why we are overconfident, and this new model offers a kind of evolutionary logic for that," Johnson said. "It's unlikely to be an accident—we're perhaps overconfident for a good reason."