In 1995, two Stanford psychologists, Claude Steele and Joshua Aronson, demonstrated thatAfrican-American college students did worse on tests of academic ability when they were exposedbeforehand to suggestions that they were being judged according to their race. Steele and Aronsonhypothesized that this effect, which they labeled stereotype threat, might explain part of the persistentachievement gap between white and black students. In the years since, this idea has spread throughoutthe social sciences. Experimental studies have detected the negative effect of stereotype threat on awide variety of groups, including women, old people, student-athletes at Swarthmore College andEcstasy users.   Last year, a week before the Democratic National Convention, David M. Marx, an assistantprofessor of psychology at San Diego State University, was sitting at a conference with a couple ofcolleagues when talk turned to the presidential election. What would the rise of Barack Obama, theywondered, do to the stereotype threat experienced by African-Americans? Their idle contemplationquickly turned into a research project, and they quickly designed an experiment to measure what theycalled the Obama effect. At a series of moments during the 2008 campaign, Marx and his colleaguesgave tests of verbal ability to selected black and white students after first priming them to focus onracial stereotypes of academic performance.   In a paper published this year in The Journal of Experimental Social Psychology, Marx and hiscolleagues reported that there was indeed an Obama effect, though it had certain limitations. Rightafter Obama's speech in Denver accepting the Democratic nomination, for instance, the negativeeffect of stereotype threat was significantly reduced for black students -- but for only those who hadactually watched the speech. Right after the election, black students again scored better, but at anotherpoint in the campaign, there was no measurable effect on their scores.   Other scholars have doubts about the phenomenon. In a separate study published in the same issueof the journal, Joshua Aronson, one of the original Stanford psychologists, found no Obama effect atall. “As much as I believe in the power of role models,” Aronson concluded, “I suspect that thegreatest contribution Obama will make to narrowing the achievement gap will be his policies, not hispersona.”
42. Which of the following statements is true about Obama effect?
(A) More than one studies have found solid proof to Obama effect.
(B) Obama effect lasted permanently for black students after the nomination speech.
(C) The participants were told about the objectives of the experiment on Obama effect.
(D) Students who didn’t watch Obama’s nomination speech suffered from Obama effect.