This finding, I believe, tells us two important things. The first is that the poorer college performance of black students may have another source in addition to the one—lack of good preparation and, perhaps, of identification with school achievement—that is commonly understood. This additional source—the threat of being negatively stereotyped in the environment—has not been well understood. The distinction has important policy implications: different kinds of students may require different pedagogies of improvement.

The second thing is poignant: what exposes students to the pressure of stereotype threat is not weaker academic identity and skills but stronger academic identity and skills. They may have long seen themselves as good students—better than most. But led into the domain by their strengths, they pay an extra tax on their investment—vigilant worry that their future will be compromised by society's perception and treatment of their group.

This tax has a long tradition in the black community. The Jackie Robinson story is a central narrative of black life, literature, and journalism. Ebony magazine has run a page for fifty years featuring people who have broken down one or another racial barrier. Surely the academic vanguard among black college students today knows this tradition—and knows, therefore, that the thing to do, as my father told me, is to buckle down, pay whatever tax is required, and disprove the damn stereotype.

That, however, seems to be precisely what these students are trying to do. In some of our experiments we administered the test of ability by computer, so that we could see how long participants spent looking at different parts of the test questions. Black students taking the test under stereotype threat seemed to be trying too hard rather than not hard enough. They reread the questions, reread the multiple choices, rechecked their answers, more than when they were not under stereotype threat. The threat made them inefficient on a test that, like most standardized tests, is set up so that thinking long often means thinking wrong, especially on difficult items like the ones we used.

Philip Uri Treisman, an innovator in math workshops for minority students who is based at the University of Texas, saw something similar in his black calculus students at the University of California at Berkeley: they worked long hours alone but they worked inefficiently—for example, checking and rechecking their calculations against the correct answers at the back of the book, rather than focusing on the concepts involved. Of course, trying extra hard helps with some school tasks. But under stereotype threat this effort may be misdirected. Achievement at the frontier of one's skills may be furthered more by a relaxed, open concentration than by a strong desire to disprove a stereotype by not making mistakes.

Sadly, the effort that accompanies stereotype threat exacts an additional price. Led by James Blascovich, of the University of California at Santa Barbara, we found that the blood pressure of black students performing a difficult cognitive task under stereotype threat was elevated compared with that of black students not under stereotype threat or white students in either situation.

In the old song about the "steel-drivin' man," John Henry races the new steam-driven drill to see who can dig a hole faster. When the race is over, John Henry has prevailed by digging the deeper hole—only to drop dead. The social psychologist Sherman James uses the term "John Henryism" to describe a psychological syndrome that he found to be associated with hypertension in several samples of North Carolina blacks: holding too rigidly to the faith that discrimination and disadvantage can be overcome with hard work and persistence. Certainly this is the right attitude. But taken to extremes, it can backfire. A deterioration of performance under stereotype threat by the skilled, confident black students in our experiments may be rooted in John Henryism.

This last point can be disheartening. Our research, however, offers an interesting suggestion about what can be done to overcome stereotype threat and its detrimental effects. The success of black students may depend less on expectations and motivation—things that are thought to drive academic performance—than on trust that stereotypes about their group will not have a limiting effect in their school world.