For years, psychologists have observed that people routinely overestimate their abilities, said study leader Dominic Johnson, an evolutionary biologist at the University of Edinburgh in Scotland.

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…

UPPER DARBY, Pa. – A pizzeria owner with mice problems he blamed on competitors tried to sabotage two rival shops by dumping mice in them Monday, authorities in suburban Philadelphia said…