Simple reaction time: it is not what it used to be

This article calls attention to the large amount of evidence indicating that simple visual reaction time (RT) has increased. To show that RT has increased, the RTs obtained by young adults in 14 studies published from 1941 on were compared with the RTs obtained by young adults in a study conducted by Galton in the late 1800s. With one exception, the newer studies obtained RTs longer than those obtained by Galton. The possibility that these differences in results are due to faulty timing instruments is considered but deemed unlikely. Of several possible causes for longer RTs, two are regarded as tenable: that RT has been increased by the buildup of neurotoxins in the environment and by the increasing numbers of people in less than robust health who have survived into adulthood. The importance of standardizing tests of RT in order to enable more refined analyses of secular trends in RT is emphasized.