The Ups and Downs of sleep and circadian Biology: Chronobiology/sleep activity.

In early 2014 as part of the international ‘Pint of Science Festival’ we developed an activity to run down’t pub alongside talks on sleep and circadian biology. This simple activity, designed to teach people more about their chronotype, is pretty easy to replicate and turned out to be great fun too. Here I’ve included all necessary explanations and kit for you to give it a go yourself – so what are you waiting for.

The Experiment

We all know at least one morning person, someone who inexplicably manages to sound chipper and look presentable before their first cup of coffee. The science of chronobiology is now helping us understand how our genetics can predispose us to being morning loving larks, night owls or indecisive hummingbirds. This test aims to find how our chronotype affects our reaction times and is best performed either early in the morning or late in the evening.


  • Each participant takes the attached questionnaire to find their chronotype (see below).
  • Everyone gets into pairs and performs the classic ruler drop reaction time test – making a note of their result (an explanation of this test can be found here)
  • Results are collected – each participant provides both their chronotype and average reaction time.
  • Experimenters collate scores and work out which chronotype showed the fastest reaction times. (see below for an example graph layout)

Example graph – note these are not real results

  • Discussion: Research suggests that your reaction time should depend on both the time of day and your personal chronotype – with owls outperforming larks in the evenings, larks outperforming owls in the morning and hummingbirds sitting somewhere in the middle (this can be seen graphically on the hand out sheet below). Amazingly, our results on the night actually supported this trend, but (like most scientific experiments) results are likely to be variable. – Note that this is a great chance to discuss scientific variability, experimental design and confounding factors (we had an interesting discussion about the effect of alcohol and caffeine on reaction times and how this could skew results).

Equipment list and resources:


  • Lots of Rulers
  • Pens
  •  Printed explanation of chronotype – Pdf
  • Printed chronotype questionnaires – Pdf1 Pdf2
  • A computer running excel and someone with a head for statistics.

Post by: Sarah Fox – for more details or advice drop us a line on

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