The Red Queen

Ridley presents the case that sexual reproduction exists as a defence against parasites, and uses that argument to explain human sexual behaviour, mate selection and the differences between the sexes. The title comes from Van Valen's hypothesis that species must keep evolving simply to maintain their relative position, which he named after the character in Carroll who runs to stay in the same place.

The core biological puzzle is that sexual reproduction halves the genetic contribution of each parent and costs enormously compared to asexual reproduction, so it requires a substantial compensating benefit. Ridley's answer, drawing on Hamilton and others, is that parasites evolve far faster than their hosts because of shorter generations, and that recombination allows hosts to produce genetically varied offspring that parasites cannot all be adapted to.

He then applies evolutionary reasoning to human behaviour, covering parental investment theory and why the sex investing more is more selective, sexual selection and the peacock problem, monogamy and its instability, the evidence around human mate preferences across cultures, and the argument that human intelligence may itself have been sexually selected.

The book is from 1993 and evolutionary psychology has been substantially contested since, both on methodology and on the interpretation of cross-cultural preference data. Ridley states positions more confidently than the evidence supports, particularly on sex differences. The parasite explanation of sex remains one of several competing hypotheses rather than a settled result. The Red Queen concept itself, that competitive advantage erodes as competitors adapt, transfers directly to business strategy.

British science writer and member of the House of Lords, former chairman of Northern Rock, writing on evolution, genomics, trade and innovation.

The Rational Optimist argues that exchange and specialisation, not individual intelligence, drive rising living standards, and assembles the long-run price and productivity evidence behind the claim. How Innovation Works applies the same method to case histories, showing invention as incremental, collective and largely detached from formal research spending.

House of Lords, Northern Rock