Tottering toddlers make surprisingly good coaches for robot football players . A team trained to mimic how infants walk comprehensively beat others trained on geometric walking patterns.

Children learning to walk look clumsy, but their meandering, start-stop stumbling exposes them to a wide variety of walking behaviour. Developmental psychologists from New York University wanted to investigate whether this variability aids learning or is an unhelpful side-effect, but that’s hard to test because long-term observation of everyday walking behaviour …