The estimates of likelihood associated with the optimistic bias are based on how closely an event matches a person's overall idea of the specific event. Some researchers suggest that the representativeness heuristic is a reason for the optimistic bias: individuals tend to think in stereotypical categories rather than about their actual targets when making comparisons. For example, when drivers are asked to think about a car accident, they are more likely to associate a bad driver, rather than just the average driver. Individuals compare themselves with the negative elements that come to mind, rather than an overall accurate comparison between them and another driver. Additionally, when individuals were asked to compare themselves towards friends, they chose more vulnerable friends based on the events they were looking at. Individuals generally chose a specific friend based on whether they resemble a given example, rather than just an average friend. People find examples that relate directly to what they are asked, resulting in representativeness heuristics.