The very act of acknowledging that they are African-American when given a test ignites in them thoughts of their own stereotype, which is negative regarding academics and that makes them do worse.
他们考试时承认自己是美国黑人,恰是这一行为激发了内心关于黑人的刻板印象,认为黑人学术水平不行,从而导致他们考得差。