It's called positive feedback bias, but its effects are largely negative. "There's nothing wrong with getting positive feedback," says Kent Harber, lead researcher of the study. But "what happens is that when the feedback is inaccurate, it doesn't provide a valid fix as to where a student is actually performing. Then they don't know where they need to best direct their efforts. It's like having a biased compass."

Furthermore, the minority students are implicitly aware that this is happening, which increases their distrust of their white teachers and fuels disinterest in schoolwork.

"When black students get positive feedback from a white, and they believe that the white is aware of their race, not only does their self esteem not get bolstered by the positive feedback -- it is actually depressed," Harber says.

In the study, 126 teachers from the New York metropolitan area were asked to edit essays supposedly written by a black, Latino, or white student. They weren't told the the student's racial demographics, but the researchers provided students' names that hinted at it (Taisha or Jarell for black students, Mark or Molly for white students). The teachers were told their comments would be delivered back to the students. In actuality, there were no students and the essays were assembled to mimic a C-grade level ability.

The researchers found that the teachers were indeed not grading the black and Latino students as critically as the white ones. This trend has been documented before, but the deeper question Harber and his colleagues were trying to answer was the source of the teacher's motivation. What compelled them to be less critical of minority students?

Political correctness is often seen as an effort to keep up appearances, but Harber's group found that something different was going on here. The teachers were trying to preserve a self image of being unbiased. The research group came to this conclusion this because the teachers didn't show bias toward the objective aspects of the essay -- the grammar or the spelling -- but rather the subjective aspects like ideas and logic. And as the paper states, "criticizing subjective features of writing raises the risk of appearing unfair because there are few established standards to justifying such criticism."



"There might be multiple causes [for positive feedback bias], but the one that seems particularly potent is a self-image concern, that the whites don't want to see themselves as prejudiced, independent of how other people see them," Harber says. "What happens, I believe, is their focus gets distracted from what are the needs of the students to what are ways that I can restore my self image."

So how can this problem be solved? Harber and his colleagues found that teachers who have greater social support at school are less likely to show a positive feedback bias toward black students. The theory is that teachers with support feel less anxious about their performance and can concentrate on being fair graders.