John Bohannon in Science Now: Both Genders Think Women Are Bad at Basic Math.
Study participants of both genders were divided into two groups: employers and job candidates. The job was simple: As accurately and quickly as possible, add up sets of two-digit numbers in a 4-minute math sprint. ... At the end of the experiment, the employers took the Implicit Association Test, which measures unconscious bias by forcing you to quickly group together various words.
The employers had limited information to make their hiring decisions. In some cases, they got nothing but a glance at the candidate—this revealed the candidate’s gender, of course. In other cases, the employers also had the candidate’s self-appraisal of how many problems he or she expected to be able to complete in the 4-minute period. And sometimes, after the employers made their hiring decision, they had a chance to change their minds after they were told by a researcher how the candidates had actually performed on a test run of the math sprint.
Men and women employers alike revealed their prejudice against women for a perceived lack of mathematical ability. When the only information that the employers had was a photograph of the candidate, men were twice as likely to be hired for the simple math job, no matter whether it was a man or woman doing the hiring [...]