The surprising result, published this week in the journal Science, suggests a new way to combat the persistent achievement gap in grades, test scores and graduation rates between black and white students, according to the researchers.
"The intervention is relatively brief, but it's powerful in a lot of ways," says Geoffrey Cohen, a social psychologist at the University of Colorado.
Cohen and his colleagues followed more than 400 seventh-grade students at a suburban public school in Connecticut. The school's population was about half black and half white.
In a series of 15-minute writing assignments, the researchers asked half of the students to complete a self-affirming exercise: to choose from a list of values -- such as relationships with friends and family, athletic ability and smarts -- and write about the value most important to them. A control group was asked to write about why the values they ranked as unimportant might matter to someone else.
In early results published in 2006, the researchers found that the exercise reduced the achievement gap between black and white students by 40 percent over one term. Researchers said the exercises benefitted low-achieving black students the most, while they appeared to have little impact on white students or already high-achieving black students.
In the new study, Cohen and his colleagues tracked the students until the end of eighth grade. They found that the benefits for low-achieving black students continued for the entire two years -- students who completed the self-affirmation exercise raised their GPA by four-tenths of a point compared to the control group. They were also less likely to need remedial work or to repeat a grade -- 5 percent as compared to 18 percent of the control group. The intervention continued to have no effect on white students and high-achieving black students.
That such a small intervention could have such big effects "surprises most people to the point that some people I know didn't believe the initial finding," says psychologist Richard Nisbett, an expert on achievement and intelligence at the University of Michigan. "But what makes it believable to me is that, as a social psychologist, I've learned that 'dinky' things sometimes have big effects."
The exercise is based on a tenet of psychological research called stereotype threat. Previous studies have found that when people are reminded of negative stereotypes about their racial, gender or other group, the stress of worrying about confirming those stereotypes can negatively affect their performance. The self-affirmation exercise, by reminding students about what is really important to them, could help reduce that stress, the researchers suggest.
And by timing the intervention to occur at a crucial period such as the beginning of middle school, Cohen says, the benefits could compound.
"Performance is recursive," he says. "If you start off at something and you're stressed and do badly, then that makes you do worse the next time. And that seems to happen a lot in middle school, where you see this downward spiral [...] By just tweaking [the students] a bit you could set them on a totally different trajectory."
But Cohen added the intervention is not a panacea to solve all students' educational woes.
"We have no illusions that this is a silver bullet," he says, "our philosophy is that the more positive forces in a child's life, the better. That includes good teachers, good homes [...] and then also psychological interventions."
He also says that there is much work to be done before the exercise can be scaled up for use in more schools. For example, the researchers want to study how the intervention would work in more racially homogenous schools, and whether it would matter if teachers knew the purpose of the exercise.
The researchers also want to better understand how, precisely, the intervention works, and what it changes about the students' academic experience.
"I think that if we could answer those kinds of questions the findings would be less mysterious, because we would know what the engines are in the school that make this intervention take off," says Valerie Purdie-Vaughns, a psychologist at Columbia University and a co-author of the study.
But Purdie-Vaughns says that as a black parent, as well as a researcher, she sees the research as crucial.
"As the parent of an African-American child, I would consider giving my child this worksheet before the first day of class," she says.