Optimism bias or optimistic bias is a cognitive bias that causes someone to believe that they themselves are less likely to experience a negative event. It is also known as unrealistic optimism or comparative optimism.
Optimism bias is common and transcends gender, ethnicity, nationality, and age.[1] However, autistic people are less susceptible to this kind of biases.[2] Optimistic biases have also reported in other animals, such as rats and birds.[3]
Four factors can cause a person to be optimistically biased: their desired end state, their cognitive mechanisms, the information they have about themselves versus others, and overall mood.[4] The optimistic bias is seen in a number of situations. For example: people believing that they are less at risk of being a crime victim,[5] smokers believing that they are less likely to contract lung cancer or disease than other smokers, first-time bungee jumpers believing that they are less at risk of an injury than other jumpers,[6] or traders who think they are less exposed to potential losses in the markets.[7]
Although the optimism bias occurs for both positive events (such as believing oneself to be more financially successful than others) and negative events (such as being less likely to have a drinking problem), there is more research and evidence suggesting that the bias is stronger for negative events (the valence effect).[4][8] Different consequences result from these two types of events: positive events often lead to feelings of well being and self-esteem, while negative events lead to consequences involving more risk, such as engaging in risky behaviors and not taking precautionary measures for safety.[4]