Putting people and things into categories is something we all do. It’s a useful shortcut but reveals biases. And it plays a role in everything from ethnic violence to childhood development, as psychologist Susan Gelman explains.

The idea that girls are emotional and “boys don’t cry” is ridiculous, says the feminist and psychologist. She tells us about books that debunk the gender myths that continue to restrict and distort our lives.

Our TV screens may be full of news about war and crime, but this masks a fall in historical terms in the number of violent deaths that’s nothing short of astonishing, says Harvard psychologist Steven Pinker. He tells us how and why this happened.

Good leaders combine iron will with a dose of humility, says the founder of groundbreaking teaching charity Teach First. He traces leadership skills back to Moses, and tells us about books we can all learn from.

The acting director of the Writing Program at Boston University argues that cowardice can still be part of our ethical vocabulary, but that we must learn from history’s mistaken identification of the traumatised as cowards.