Born to be biased? Unrealistic optimism and error management theory

When individuals display cognitive biases, they are prone to developing systematically false beliefs. Evolutionary psychologists have argued that rather than being a flaw in human cognition, biases may actually be design features. In my paper, I assess the claim that unrealistic optimism is such a design feature because it is a form of error management. Proponents of this theory say that when individuals make decisions under uncertainty, it can be advantageous to err on the side of overconfidence if the potential gains through success are high and the costs of failure are low. I argue that there are a number of conceptual problems in matching the theory with the existing data. I also show that there is empirical evidence against the error management hypothesis.