Reaction Time

Reaction time refers to the amount of time taken after the presentation of a stimulus for a participant to make a judgment and then provide a response. An example would be providing a person with a word and then the person tapping on a key to denote whether the word was a noun, verb, adjective, adverb, or article. The exercise provides a means of evaluation of the stimulus and the generation of a response on the part of the participant. The research question deals with how long the participant takes to respond to the particular stimulus. The consideration is whether or not particular sounds or stimuli provoke a faster recognition and subsequent response. This entry provides some examples of reasons for testing reaction time, reviews various warning systems that trigger specific reactions, and discusses how experimental investigations compare how various options impact the nature of reaction time. While such effort may appear hard to justify in terms of a practical application for action, there are a number of circumstances in which a quick response to a sound may be desirable. Suppose a surgeon, an airplane captain, astronaut, driver, or soldier needs to respond quickly to some stimulus to avoid an accident or perform some action in response to some random or unpredictable event. Essentially, the challenge is to create a message system that will create a recognition and response on the part of the person in as short a time as possible to the particulars of the identified situation. The challenge of whether a sound, a colored light, an action, or some other environmental change best produces that reaction serves as the basis for an entire set of considerations. The investigations measure the success in terms of how quickly the person becomes alert to the new event and then responds appropriately and correctly.

Theoretically, the idea that a person responds more quickly to something familiar or identifiable forms the basis of a lot of training programs. The goal of many institutions requiring a response from persons is the generation of sounds (e.g., alarms, gongs) or lights (e.g., flashing, colors) that create a common automatic response by organizational members. The requirements of coordinated action in a timely fashion creates the need to provide some means of communication recognized by persons understanding the code. In some circumstances, words may not be desirable; for example, simply yelling “tornado” may not create given the distances involved. The use of the tornado siren creates a sound that, when recognized by a person hearing the wailing, leads to action (i.e., taking shelter). Much research goes into the examination of warning systems and how to convey information in a concise and timely manner to audiences across distance or engaged in some other task that must halt.

The experimental design of such investigations often involves the use of a computer and the timing of the presentation of the stimulus and the length of time until an appropriate reaction takes place. The ability to record a very precise time, often in hundreds or thousandths of a second, permits a very precise ability to differentiate cognitive processing times to a fine degree. The recognition can involve not only recognition of verbal (written or oral) messages but also reaction to symbols or elements of pictures or videoclips as well. Technological sophistication permits a variety of visual and/or auditory combinations and the measurement of response to those situations.

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