Studious white, East Asian, and South Asian men are presumed to be good at maths and science, including computer science. They are shunted in that direction, encouraged by parents and teachers; once enrolled in programmes their mistakes are taken as learning opportunities rather than evidence of a lack of aptitude. Absorbing those messages boosts their confidence and assumptions about future careers, to the extent that at least some number — based on students I have mentored — worry that they may not turn out to have an aptitude for an unexpected path into law or politics.

These men are subject to positive cultural stereotypes. Those who really are good at maths and computer science flourish; those who do not in fact have a natural aptitude will still do better than they might otherwise — an environment of positive encouragement leads to hard work and good results.

I have experienced the power of expectations first hand. Early in my career as a professor, I realised that I was smarter around one colleague because he expected me to be smart. He had a brilliant mother and wife and actively mentored women, looking for talent and intelligence where others often missed it. Plenty of work environments are less positive, of course. National security discussions are still largely dominated by men who often still do not treat women as their intellectual equals. In those groups it is much, much harder to be smart — speaking to a room