Studies have shown that it is very difficult to eliminate the optimistic bias. Some commentators believe that trying to reduce it may encourage people to adapt to health-protective behaviors. However, research has suggested that it cannot be reduced, and that efforts to reduce it tend to lead to even more optimistically biased results. In a research study of four different tests to reduce the optimistic bias, through lists of risk factors, participants perceiving themselves as inferior to others, participants asked to think of high-risk individuals, and giving attributes of why they were at risk, all increased the bias rather than decreased it. Other studies have tried to reduce the bias through reducing distance, but overall it still remains.