Circuit Playground Bluefruit over M75 canon barrel, photograph by Petar Milosevic.

CPX Results

This is a set of graphs showing the results from various trials on a Circuit Playground Express. The graphs only show values between 0ms and 450ms. Any values less than 100ms are not used in the calculations for arithmetic mean and sample standard deviation (sd). The graph on the right shows the same data in the form of a violin plot. This shows the distribution and provides some indication if there are values above 450ms.

The test conditions vary wildy - these are described in the title on each graph. The degree of practice by the test subject varies too. The later tests were conducted with a button rather than the original use of a touch pad. These three factors make comparisons between the test subjects hard.

Graphical summary of results from Reaction Timer running on a Circuit Playground Express.

See results for the individual graphs.


  • Reaction to an auditory stimulus is faster than a visual one - this is a common and well-known result. The variance may also be less but more data is needed to prove this.
  • Minimum reaction times do not vary considerably with age but very young children may struggle with consistency. 
  • Auditory reaction time decreases with increase in background noise even when there are no sounds which mimic the test sound.
  • The auditory reaction time test is much harder if another test is being performed at the same time even if the sound's pitch is different.
  • The absence of a penalty for false reactions probably decreases reaction times but this was not studied explicitly.
  • Distribution does not follow the normal distribution reducing the significance of the mean. It's generally asymmetric unless the subject can maintain a very high level of attention during test.
  • The movement time appears to be less for a button compared to cautious use of a capacitive touch pad.
  • Very tempting to cherry pick results and discard slow times leading to a form of sampling bias.

This guide was first published on Jan 20, 2020. It was last updated on Jan 20, 2020.

This page (Reaction Timer Results) was last updated on Oct 22, 2021.

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