Imperfect Cognitions

In our everyday conception, an optimist is someone who looks at the bright side and expects good things to happen. The psychological literature distinguishes between different kinds of optimism: dispositional optimism and unrealistic optimism (also known as the optimism bias). Which of these types of optimism corresponds to our lay conception and how are they related to each other? Do these types of optimism differ in their effects?  Dispositional optimism is conceptualized as a general tendency to expect good outcomes and as a fairly stable personality trait. The optimism bias on the other hand is supposed to be a cognitive bias whereby people overestimate the likelihood of encountering specific positive events and underestimate the likelihood of encountering specific negative events. This unrealistic estimate can either be comparative or absolute. In the first case, we rate our own prospects as better than those of comparable others, in the second, we overestimate our...