In the Seventies fewer than 10 per cent of musicians in major US orchestras were women. Auditioners claimed that there was a simple reason: men are better performers. Then someone had a neat idea: conduct auditions behind a curtain so that selectors are unaware of the gender of the performer. The number of women suddenly started increasing, reaching 40 per cent today.

This example reveals the power of subconscious stereotyping. Judgments often tumble out of our brains not because of evidence, but according to covert assumptions that permeate the way that we view the world. Women are often disadvantaged by this tendency. The unspoken idea that they are weaker, more fragile, less logical (and less capable of performing in orchestras) means that they are not