Wherever there's judgement there's noise, and more than you think. In the criminal justice system, we saw variability between judges in the severity of their sentencing for equivalent crimes. In business, you may have a company where someone in hiring says, 'bring everyone in, I think they're great' and you end up with a company full of people who shouldn't be there.

I'm particularly interested in the human propensity to copy behaviours that lack any kind of knowable causal structure. This is how we learn arbitrary conventions—and I think it originates in a distinctively human way of building group identities. I describe ritual actions as causally opaque. We engage in this kind of behaviour even more enthusiastically when we're anxious about being excluded or left out.

The vast majority of people- if they can benefit from something or make some money, will look the other way. It's personal greed, without thought about the consequences.

Our brains are constantly taking shortcuts to inform us about the world and this introduces an intrinsic error which our brains are filling in. By the time we 'see' something perceptually, we're a fraction of a second behind real-time.

Even if we end up with better regulations, we'll still have 300 million guns washing around the US, and that's going to be a huge problem for decades, because guns last a long time.