"Talk to the hand," growls the threat, showing what comes of listening to the hand. When the body is flushed with the alarms that ready it for conflict, the signals it sends to the brain confirm the sense of crisis. The brain is quicker to revise its response than the body, which is why it is often a good idea to separate men who have taken drink and umbrage with each other. Their brains may attend to appeals for calm, but these are swamped by the current of wrath that still swells in their bodies.
According to Robert Sapolsky, it is also why a woman will revive an argument that a man vainly imagines is behind him. Women's autonomic nervous systems, the biologist and primatologist explains, take longer to calm down.
This account is typical Sapolsky fare: brisk, unapologetically biological, and stimulating one way or another. Perhaps the most telling thing about it, though, is that although it has an air of novelty, the basic insight is due to the 19th-century psychologist William James. Its unfamiliarity suggests a long-standing reluctance to engage with "our lives as animals".
All the experts agree that nature and nurture are not either/or. All agree it's all about interaction. But for one camp, the underlying message is that evidence for inherited influences on human psychology can be disregarded, while the other camp sees heredity as the signal, and environment as the noise.
This continuing polarisation is why we need commentators like Sapolsky, and why this collection of articles is excellent value. His chief virtues are a liking for surprises, a need to know, and a sense of science as knowledge in motion. He is drawn to the findings that don't fit, rather than those that make pictures look neater. And he doesn't indulge his realism by letting it subvert his liberalism.
With each new theory, new contradictions appear. Hen birds, one theory runs, choose attractive males as mates because the latter are fit in the biological sense. Sure enough, a study found that ducklings sired by attractive mallard drakes were more likely to survive - but only because the mothers invested more in them, providing larger eggs. These ducks appear to be fashion victims. "They should know better than that," Sapolsky reflects, disappointed to find that silliness is not uniquely human.
Marek Kohn's 'A Reason for Everything' is published by FaberReuse content