Self-confidence also has beneficial social effects, since it signals that you are capable of winning. As a result, people tend to be more self-confident than can be rationally justified, and they’re also built to counteract those effects. For example, they are risk-averse. If you are only as confident as is rationally justified, but you are still risk averse etc., you will avoid taking actions that would benefit you.
Self-confidence also has beneficial social effects, since it signals that you are capable of winning. As a result, people tend to be more self-confident than can be rationally justified, and they’re also built to counteract those effects. For example, they are risk-averse. If you are only as confident as is rationally justified, but you are still risk averse etc., you will avoid taking actions that would benefit you.