Abstract: Optimistic bias means people have a tendency to think that positive evens are more likely to happen to themselves and negative events are more likely to happen to other people. There are two methods to measure optimistic bias, which are direct and indirect comparison. Feature of event and individual factors are the leading influencing factors of optimistic bias. Egocentrism and focalism are the main psychological mechanisms to engender optimistic bias. Optimistic bias has both positive and negative effect to individuals. Future research directions include: (1) developing more scientific and feasible measures; (2) examining optimistic bias on individual level; (3) studying optimistic bias combined with pessimistic bias, and (4) investigating cognitive neuroscience mechanisms of optimistic bias.

Key words: optimistic bias, unrealistic optimism, feature of events, individual factors, psychological mechanism