Humans generally exhibit a pervasive future bias in favour of optimism. We overestimate the likelihood of success in work, relationships and financial investments. Similarly, we underestimate the probability of experiencing negative events such as, serious illness or financial ruin. The optimism bias is widely considered as one of the most reproducible, prevalent and robust cognitive biases observed in psychology and behavioural economics. The catastrophic impact of the recent economic collapse has laid this cognitive bias bare. In this introductory overview, current (...) understanding of the neural basis of the optimism bias is explored. Topics considered include: converse negative biases in depressive illnesses, the role of dopamine in optimism bias generation and modulation and evidence from functional neuroimaging studies. Research on the optimism bias has afforded us a unique window into decision-making, reward-processing and the potential for systematic irrationality in the human mind. (shrink)