I was playing pinball the other day, and I wasn't doing very well - my reactions were far too slow it seemed.

My question is - Firstly - how can someone's reactivity measured/determined? I imagine there are some quite conclusive tests.

Secondly - what affects people's reaction times? I imagine alcohol impairment and sleep deprivation affects them - are there other common factors? Is there anything that increases reactivity?


Reaction times can be measured by a variety of techniques in the lab. The simplest test is to present a stimulus to a test subject and instruct the subject to press a button as fast as possible after the stimulus is perceived. Responses can be measured by using a response box. Often-used stimuli are either visual (e.g., a colored dot that pops up at random times on a computer screen), auditory (e.g., an acoustic beep), or tactile (e.g., a vibratory buzz or tap on the finger). These tests measure the reaction time from stimulus presentation up to the moment the subject presses the button. Hence, obtained response latencies include peripheral sensory processes, central sensorimotor processing in the brain, and motor output.

Age increases reaction time, mainly due to a slowed motor output (Woods et al., 2015). The stimulus modality also affects response latency. Visual stimuli result in long reaction times, tactile stimuli in shorter latencies, and auditory stimuli induce the shortest reaction time (Ng & Chan, 2012). These differences reflect the slow sensory processing in the visual system and the fast response of the auditory system. Neuro-supressants, such as alcohol, tranquilizers, antiepileptics- and anesthetics all increase reaction times (e.g., Mitchell et al.,, 1993).

- Mitchell et al., Pediatrics (1993);91(1):101-5
- Ng & Chan, Proc IMECS II (2012)
- Woods et al., Frontiers Human Neurosci (2015); 9:131-12p

  • $\begingroup$ This is a very good answer. Could you expand on the things that affect reaction time? eg. drugs, sleep, mood. $\endgroup$
    – dwjohnston
    Sep 26 '15 at 15:22
  • $\begingroup$ @dwjohnston - Done. $\endgroup$
    – AliceD
    Sep 26 '15 at 21:09
  • 1
    $\begingroup$ @dwjohnston, a great many things affect reaction time. The topic you're asking about is huge. As a general rule, a change in reaction time (absent chemical or physiological alterations) is taken to reflect an algorithmic change (or strategy change) in the brain. In other words, processing time changes because processing steps have changed. From there, we can make certain inferences about which processes are engaged in the task at hand ... and now you understand why this topic is so vast! $\endgroup$ Sep 28 '15 at 13:22

I did some hobbyist experimentation in this area and wrote an article for Adafruit on reaction times recently. Their "arduino-like" boards make a good platform for this and don't need any extra electronics. I would avoid use of a laptop or general purpose computer as there are many software components adding latency and some of them aren't predictable. Even something as simple as the innocent-looking keyboard adds latency. LEDs are far better due to high speed response than LCD devices for visual stimuli too. I would also suggest verifying the accuracy of any measuring equipment with a high speed camera - many smartphones have a 240fps mode nowadays.

Have a look at Adafruit Learn: Circuit Playground Bluefruit Quick Draw Duo if you're interested. There are two parts, the first is a game, the second measures reaction times and sends them over USB to the host computer. If you are working with young children the game as a first phase might be useful to get them interested. The graphs are just simple R/ggplot2 plots of the console output.


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