Reaction time

Reaction time is the interval time between the presentation of a stimulus and the initiation of the muscular response to that stimulus. A primary factor affecting a response is the number of possible stimuli, each requiring their own set of responses, that are presented.

Definition

A stimulus is any object or event that elicits a sensory or behavioral response in an organism. In psychology, it is any energy change that is registered by the human senses. The ability for an organism to react to a stimulus is determined by the organism's reaction time.

Factors affecting reaction time

There are many factors that can affect reaction time. Reaction time is faster when there is only one possible response (simple reaction time) as opposed to when there is more than one possible response (choice reaction time). Reaction time also decreases as the intensity of the stimulus increases. Other factors that can affect reaction time include age, sex, left or right hand, central versus peripheral vision, practice, fatigue, fasting, breathing cycle, personality type, exercise, and intelligence.

Measurement

Reaction time can be measured using a variety of methods, including the ruler drop method, the psychomotor vigilance task, and the go/no go task. The ruler drop method is a simple and common way to measure reaction time, where a ruler is dropped and the time it takes for the person to catch it is the reaction time. The psychomotor vigilance task measures the speed with which subjects can respond to a visual stimulus. The go/no go task measures the reaction time of a subject when they are given two stimuli and are told to only respond to one of them.

See also

• Psychomotor vigilance task
• Go/no go
• Stimulus (psychology)