ABSTRACT
The minimum time that elapses between the moment an unexpected STIMULUS is presented and the beginning of a motor RESPONSE to it is known as the reaction time (RT). It includes the time of the cognitive processes that link stimulus to response plus the time of noncognitive sensory and motor processes. RT is a generic term to cover several different types, which we will discuss first, before moving on to consider influences on reaction time, such as exercise and age, as well as MENTAL PRACTICE. Disjunctive reaction time is relevant to most activity-based pursuits
as this covers situations in which there are complex stimuli and responses available. It includes choice reaction time. In many competitive situations, athletes are presented at unpredictable times, not simply with a single STIMULUS and one response, but also a variety of distinct, fast-changing stimuli and a range of possible responses. The athlete has decisions to make; he or she must select an appropriate response to each of the stimuli. The choice reaction time describes how long it takes the athlete to make and implement the appropriate selections. Closely related to this is the discrimination reaction time. In some
situations, an individual must respond to some auditory or visual stimuli and desist from responding to the others. In other words, a rapid discrimination between the various stimuli must be made. In most sports, deception or faking is so commonplace that skilled athletes need to be able to refrain from responding needlessly to dummy stimuli. Another variant of RT applicable to sports is complex (sometimes
called compound) reaction time where two or more stimuli are available and two or more responses are employed in quick succession or simultaneously. This is common in ball sports where the release or the contact with the ball usually corresponds with other responses. When the term RT is not qualified by any of the above, it usually
refers to simple reaction time, in which a single stimulus requires a single response and describes the times between the two. These are rare in sports: a tip-off in basketball in which a tossed ball works as a stimulus for a single response might serve as an example. The starter’s gun at the start of a sprint is another-though this is the subject of some dispute, as we will see. In the early 1950s, research by W. E. Hick found that the more
choices we are presented with, the more time we need to react appropriately. Alternatively, P. M. Fitts indicated that, if RT remained constant when the volume of stimuli went up, then accuracy was
sacrificed. It was thought that humans had a ‘‘capacity-limited INFORMATION PROCESSING channel’’ and that there would inevitably be a sort of trade-off: speed for accuracy or vice versa. More recently, other accounts of SKILL EXECUTION have indicated
that RT is not so fixed and can be changed through extended repetition in training as well as other means. For instance, research has focused on the impact of aerobic exercise on age-related slow-downs in RT. While the evidence that exercise programs can ameliorate decline in cognitive function is mixed, Courtney Hall et al. indicate the possibility of exercise-induced cognitive improvements, specifically in EXECUTIVE CONTROL functions in the elderly. Executive control is a high-level function associated with the frontal lobe of the brain. Even mental practice (that is, in the complete absence of motor
response) has been shown to be effective in improving reaction time and not only among the elderly, according to George Grouios. As if to warn against setting finite limits for RT, research has cast
doubt on the International Association of Athletics Federation’s standard that the fastest possible auditory reaction time is 100 milliseconds (100 one-thousandth of a second) and that anything quicker is a false start. Matthew Pain and Angela Hibbs dispute this, demonstrating that simple auditory reaction times of under 85 milliseconds are possible.
