“Decades of research have shown that internalizing racial stereotypes contributes to the achievement gap between black and white students. (For instance, African American students perform worse than whites on standardized tests when they are asked to fill out a form beforehand disclosing their race.)

A team of researchers wondered if the ascendance of an African American to the country’s highest office could lessen this phenomenon, so they administered a 20-question standardized test to more than 400 Americans, before the election and again right afterward.

On the first test, blacks did indeed score worse than whites overall, but on the second their scores improved so dramatically that the performance gap was erased entirely. As the New York Times reported, “the inspiring role model that Mr. Obama projected” erased the self-doubt that had hindered black performance. While this was only one study and its effects were probably temporary, it illustrates how strongly our beliefs can affect our abilities.