Unfit or weak people react sooner to sounds of approaching danger than strong, healthy people. Unfit or weak people react sooner to sounds of approaching danger than strong, healthy people. This may be an evolutionary adaptation to allow them a larger margin of safety, says a new study. Test subjects listened to a sophisticated sound system that mimicked an approaching object, at the College of Wooster in Ohio, US. The ‘virtual object’ sounded like a motorcycle passing on a highway, approaching the subject at 15 m/s and then whizzing past them. The subjects were asked to hit a key when they thought the sound was right in front of them. Fitness was measured by two variables: heart rate after a bout of moderate cardiovascular exercise, and muscular power, measured by the strength of their hand grips. Almost everyone underestimated the time of arrival, hitting the key before the sound actually arrived. But people who were less physically fit hit the key sooner than those who were more fit, “It’s beneficial [for the weaker] to react sooner rather than later,” said the scientist leading the study. “The cost of responding too early is far less than the potentially fatal cost of responding too late.” The difference was less than a second. Nevertheless, this systematic perceptual error might provide a selective advantage. Perceptual bias might be a behavioural adaptation shaped by evolution. Women typically responded sooner than men, who on average are physically stronger. Plus, comparative studies in Rhesus monkeys showed the same biases, suggesting a biological basis for the results.
