What is unrealistic optimism?

- There are a number of controversial questions regarding the nature and causes of unrealistic optimism.
- We argue that unrealistically optimistic cognitions should be considered beliefs rather than desires or hopes.
- Optimistically biased beliefs are frequently false but establishing falsity in individual cases is difficult and sometimes impossible.
- Optimistically biased beliefs are epistemically irrational because they are unwarranted and their responsiveness to counter-evidence is limited.

Here we consider the nature of unrealistic optimism and other related positive illusions. We are interested in whether cognitive states that are unrealistically optimistic are belief states, whether they are false, and whether they are epistemically irrational. We also ask to what extent unrealistically optimistic cognitive states are fixed. Based on the classic and recent empirical literature on unrealistic optimism, we offer some preliminary answers to these questions, thereby laying the foundations for answering further questions about unrealistic optimism, such as whether it has biological, psychological, or epistemic benefits.