When it comes to ideology, dictionaries seem to go out of the window. They talk soberly about systems of belief and schemes of ideas, without reference to the content or character of such schemes. But in public conversation, ‘ideology’ typically means a system of belief that the speaker regards as misguided or undesirable. Leor Zmigrod, a scientist who studies how political thought operates at the level of neural circuitry, shares this perception. After exploring the history of the concept, she sets out an understanding of ideology as dogma originating in cognitive inflexibility. In The Ideological Brain, she lays out a vision for ‘a mind that is ideology-free’.

Zmigrod places herself in a tradition of thinkers seeking to identify psychological factors behind dogmatic and intolerant political attitudes. The landmark study in this field is The Authoritarian Personality, a book published in the aftermath of the Second World War. It is most strongly associated with its first-named author, Theodor Adorno, but Zmigrod highlights the contribution made by the second-named author, Else Frenkel-Brunswik. She describes Frenkel-Brunswik’s studies of children’s political beliefs with imaginative sympathy, and discusses the resonances with her own investigations.

One of these investigations looked at the psychology of Brexit through a series of tests requiring people to sort cards according to criteria such as colour and shape. The rules for sorting the cards changed from one exercise to the next and the subjects’ ability to cope with rule changes