Stereotype threat is a situation in which, when someone is aware of their minority status and reminded of stereotypes about one's minority group, one tends to underperform in the skill in question.
Stereotype threat is psychological jargon: that is, it is a series of findings in the psychological literature about how precisely how skill level drops when people are reminded of various stereotypes about their group. As Wikipedia says "Although decreased performance is the most recognized consequence of stereotype threat, studies have shown that it can also lead individuals to blame themselves for perceived failures, self-handicap, discount the value and validity of tests and other performance tasks, and disengage from situations and environments that are perceived as threatening."
See also
- Letting the side down, about conscious fears and decisions about not trying new skills or exhibiting them in public when they might reflect badly on all women.