Diversify your Syllabus.
Some studies show that the presence or invocation of role models from underrepresented groups reduces stereotype threat in those groups. One way to introduce philosophical role models into your classroom is by assigning authors from underrepresented groups. Keep in mind that while the traditional canon of Western philosophy is overwhelmingly written by white men, you can still teach secondary sources about the canon by philosophers from underrepresented groups and unearth work on similar topics from less well-known people. The canon itself developed under unjust conditions, so while we cannot expect history to change, we can change the way we teach it.
Include a Statement of Past Fairness on your Syllabus
As you know, assuring students that a test has shown no differences in the past can reduce or eliminate stereotype threat. You may also consider adding a statement to this effect to the syllabus. One of my law school professors, Glenn Cohen, includes such a statement on his Civil Procedure syllabus:
Gender and Performance: There is some psychological research suggesting that some women bring inaccurate self-defeating views of how well they will perform in law school, and that such attitudes can create self-fulfilling prophecies. Luckily, there is also psychological research suggesting that telling students that there are no gender differentials in performance in a class can debias them and prevent these tendencies. In every year I have taught the course there is no statistically significant difference on gender between the students who do well in the class. Consider yourself debiased. For more on the fascinating issues about gender and law school, a good starting read is my colleague Lani Guinier’s article, Lessons and Challenges of Becoming Gentlemen, 24 N.Y.U. REV. L. & SOC. CHANGE 1 (1998).