Reaction time: What is it and which factors are involved?

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Reaction time is an important component in cognitive psychology. Reaction time in a nutshell, in a simple task, is the time between a stimulus and a response. When explaining it a bit more, reaction time is the necessary time to identify a situation, decide the reaction that is going to be made, and voluntarily initiate and execute that reaction via activation of specific muscles. Now you know what the definition of reaction time is, we would like to further explain the components and factors involved in reaction time.

In the past few weeks, we saw how important reaction time is. Did you know that there were four shootouts during the European Championships Soccer 2020? In total, there were over 50 penalties taken during the Euros 2020. We would like to explain how reaction time works, evaluating one of these penalties. Namely, the penalty that was taken by Mbappé for France during the shoot-outs of France against Switzerland.

The moment Mbappé went to take that penalty during the shootout, goalkeeper Sommer knew in which corner Mbappé normally shoots his penalties. But for this moment, let us pretend Sommer did not know that. So imagine Sommer went in unprepared and therefore the only chance for Sommer to save that penalty was to react to the body language of Mbappé during the very first moments of Mbappé taking that penalty. Sommer would fully focus on the core, hips, legs, feet, and ball to predict where Mbappé will shoot this penalty. Thus, Sommer, his eyes would watch Mbappé and the ball in anticipation of how this penalty would be taken. Broadly, this visual information gained will be sent via a neural pathway to the visual cortex in the occipital lobe of the brain. The information will be processed in the cerebrum and that is the moment that Sommer will be aware of the movements Mbappé and the ball are making. When being aware of Mbappé’s movements, Sommer has to decide what his reaction will be. That decision-making includes several processes in the brain, further explained in earlier articles. Eventually, the reaction Sommer chooses will be executed by his body. This will be done by neural stimulation of the specific muscles Sommer needs to contract and relax in order for him to save that penalty. Fine-tuning of Sommer his reaction when the ball suddenly deviates from the predicted pattern is done by the cerebellum.

To roughly summarize reaction time, there are 3 main processes:

  1. Sensory pathway of the stimuli to the brain.
  2. Cortical cognitive processing of the stimuli and decision making in mainly the cerebrum.
  3. Motor pathway to the specific muscles to execute the decision.

Every component of the reaction time has its own duration. The amount of time for processes number 1 and 3 are more or less constant. The most variable component of reaction time is cognitive processing and decision making. Factors that can affect the reaction time are among others: age, sex, practice, fatigue, exercise, and the level of intelligence. Another factor that influences the reaction time is the complexity of the reaction time task. It is found that the fewer stimuli and responses there are, the faster the duration of cognitive processing and thus reaction time is. Schmidt & Lee found that every time the amount of stimuli-response choices doubled, the reaction time increased by 150 milliseconds.

In the software tool produced by Aristotle Cognitive Training, one of the outcome measures is reaction time. By measuring the reaction time, mental chronometry, we can measure the cognitive processing speed. This way, our tool can measure the improvement in reaction time and thus cognitive processing of for example athletes, employees, and patients.


  • Engineering, H. Steffan. (2013). Encyclopedia of Forensic Sciences. Reaction Time.
  • Jain, A., Bansal, R., Singh, K.D. (2015). A comparative study of visual and auditory reaction times on the basis of gender and physical activity levels of medical first year students. International Journal of Applied Basic Medicine Research. 5(2): 124-127.
  • Lee, T.D., Schmidt, R.A. (2011). Motor Control and Learning.
  • Kranzler, J.H. (2012). Mental Chronometry. Encyclopedia of the Sciences of Learning.