Mental Chronometry

reaction time can be impressively fast under optimal conditions. For example world class sprinters at the 2008 Beijing Olympics sometimes had reaction times (RTs) to the starter's pistol that were as quick as 110 milliseconds (110 ms is just a bit more than 1/10th of a second). A false start is defined by the International Association of Athletics Federations (IAAF) as a reaction time (in this context, a leg movement detected by electronic sensors time-locked to the starter's signal) that is shorter than or equal to 100 ms. This value was decided on because objective tests have shown that no one, however much he or she practices, can produce a voluntary RT that is equal to or faster than 100 ms from the onset (the beginning) of a sensory event like a tone or a flash of light. Any task, even one that simply demands a prepared action to a cue (for example, an athlete beginning to move as quickly as possible on the starter's signal), takes a certain duration that reflects the time course of underlying mental events. From a meth-odological standpoint, the average RT will tell us nothing about the processing steps involved in a particular task. The athlete is in some preparatory state that will rapidly trigger a particular