False Consensus Effect

People tend to overestimate the extent to which other people share their opinions, behavioral inclinations, and preferences, a bias known as false consensus. In a typical study, participants might be asked whether or not they agree with a statement (e.g., “use of the death penalty is appropriate in some cases”), after which they are asked to estimate the percentage of their peers who would also endorse the statement. Investigators then compute a score that represents the difference between the estimate given by those who endorse the statement and those who do not. For example, suppose 70% of individuals in a sample endorse the death penalty (and thus 30% do not). If the 70% who endorse it estimate that 60% of their peers agree with them, ...