Assesses the ability to react under simple stimulus constellations (simple and choice reactions).
Reaction time can be measured for both simple choice and multiple-choice reactions. Light and sound stimulus modalities are available, with a choice of the colors 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.

The main fields in which reaction times are measured are traffic psychology, personnel psychology (safety assessments), sports psychology and pharmacopsychology. In recent years there has also been an increase in the use of reaction time measurements in neurology, psychiatry, rehabilitation, and labor medicine.

Respondents react as quickly as they can to optical or acoustic signals.
This involves pressing or releasing a button as quickly as possible when a simple light signal (yellow or red light), a tone or a combination of two stimuli (yellow and tone or yellow and red) is presented.

S1: Simple reaction, yellow – reaction to critical stimulus
S2: Simple reaction, tone – reaction to critical stimulus
S3: Choice reaction, yellow/tone – reaction to critical stimulus combination
S4: Choice reaction, yellow/red – reaction to critical stimulus combination
S5: Choice reaction, yellow/tone, yellow/red – reaction to critical stimulus combination
S6: Simple reaction, white under monotonous conditions
S7: Measurement of alertness – simple reaction, yellow (with acoustic cue)
S8: Measurement of alertness – simple reaction, tone (with optical cue)

The following main variables are scored, depending on the test form:

• S1-S6:
  Mean reaction time: measure of reaction speed in response to relevant stimuli.
   
• S7/S8:
  • Difference in mean reaction time without and with a cue: indicator of difference in reaction time between tonic and phasic alertness.
  • Difference in mean motor time without and with a cue: indicator of difference in motor time between tonic and phasic alertness.