Application: The RT’s special test forms enable reaction time and motor time to be measured. Phasic alertness can also be measured by some test forms. Several test forms can be used with children from the age of 6.
Main areas of application: traffic psychology, clinical and health psychology, personnel psychology, sport psychology, educational psychology.
Theoretical background: Dorsch (1994) defines reaction time as the time that elapses between a signal and the start of the mechanical response movement when the respondent is instructed to react as quickly as possible. Since such response times need to be measured in milliseconds, the test instrument used must be very precise and highly reliable.
With the RT is it possible to measure reaction time for both simple choice and a multiple-choice reactions. Light and sound stimulus modalities are available, with a choice of the colours red, yellow or white, so that different stimulus constellations for the measurement of reaction time can be created. These can range in the different test forms from individual stimuli to simultaneous or sequentially presented stimulus combinations. The use of a rest key and a reaction key makes it possible to distinguish between reaction and motor time.
Administration: The Response Panel is used as the input device. An animated instruction phase and an errorsensitive practice phase lead on to the task itself. The test involves the presentation of coloured stimuli and/or acoustic signals. The respondent is instructed to press the reaction key only when specific stimuli are presented and, having pressed the key, to return his finger immediately to the rest key. The use of headphones ensures the exclusion of distracting noises.
Test forms: Forms S1-S5 assess reaction time and motor time in response to simple and complex visual or acoustic signals. Form S6 is particularly suitable for measuring changes in reaction time over a relatively long period of time under monotonous stimulus conditions (vigilance). Forms S7-S8 are used to measure alertness. Forms S9-S10 are particularly suitable for assessment situations in which absolute reaction times are important; in these forms response times are not split into reaction time and motor time.
Scoring: The following main variables are calculated, depending on test form: mean reaction time and mean motor time, difference in mean reaction time with and without cue and difference in mean motor time with and without cue. Means are calculated using a Box-Cox transformation; this ensures that they provide an optimal representation of the central tendency of the distribution of the reaction times.
Reliability: Reliabilities (Cronbach's alpha) in the norm sample vary between r=0.83 and r=0.98 for reaction time and between r=0.84 and r=0.95 for motor time.
Validity: Content (logical) validity is given for the Reaction Test. The presentation of an individual stimulus for one second is such a simple requirement that it can be assumed that nothing other than a reaction to that stimulus occurs. Validity studies in the field of traffic psychology demonstrate among other things that there is adequate convergent validity.
Norms: Norm samples of the size N=75 to N=855 are available for all forms of the RT; some norms are also available separated by age, gender and educational level. For a number of forms special norms are also available for school children and for drivers who have committed motoring offences.
Time required for the test: Between 5 and 10 minutes (including instruction and practice phase), depending on test form.