honey hit to the brain when we shine. There is evidence that schizophrenia is associated with a dysfunctional dopamine system, which might help explain the overconfidence in their beliefs, especially beliefs in powerful religious icons. Winning boosts confidence, which increases the chances of winning again. This is a highly adaptive cycle that can lead to overconfidence. Dominic Johnson took advantage of the research on human and animal competition to explore the link between overconfidence, testosterone, and war within the context of a simulated game. Each subject played the role of a leader in a country at war with another over diamond resources. The goal of the game was to accrue the highest level of resources or defeat the neighboring country. Though war games on a computer can not capture the full reality of war, the fact is that military specialists throughout the world use simulations to prepare combatants for some of the strategic and emotional problems they will confront. Most subjects judged that they would outcompete their opponents, and this was exacerbated in males relative to females. Those who believed that they would whip their opponents actually had the worst records, suggesting that they were not only uncalibrated but that their distortion of reality led to costly outcomes. Those with the highest expectation of victory had the highest testosterone levels and were most likely to launch unprovoked attacks on their opponents. Whether in real life or in the simulated world of computer games, brimming overconfidence can lead to a distorted sense of risk and the odds of victory in war — or any competitive arena. Though this is a costly strategy, there are clear evolutionary benefits under conditions explained by Trivers and Johnson. Self-deception is favored when opponents have imperfect information about their strengths and weaknesses, and where the payoffs are high relative to the costs. Self-deception leads individuals to go for it, convincing the