The first big psychological study of Brexit voters has found that people who voted Leave in the 2016 UK referendum share many personality traits with Trump supporters in the US, and supporters of far-right political parties in Europe. In particular, they were far more likely to have an “authoritarian” personality.

Around a third of people in western societies have authoritarian personalities. This personality type is partly determined by genes, and features a strong desire for order, obedience, conformity, and cohesion within …