The Stinging Foot Spray Experiment: How data helps in emotional situations

“It stings too much!” cried my young daughter after the first spray of the medicine.

Mud at the Latitude Festival 2012
Mud at Latitude Festival

As a result of a muddy weekend camping at a music festival she had developed Athletes Foot for the first time. The only child-suitable treatment available at the chemist was a foot spray.

I had a dilemma; to help her foot heal as soon as possible we needed to continue to use the spray twice a day, but she was clearly upset and distressed by the stinging. It was difficult to tell how painful it really was. How to move forward?

“Could we do an experiment to work out how ‘stingy’ the foot spray is? On a scale out of ten, where 10 is the most painful you could imagine, how much does it hurt now?”


“OK, could you hold this stop watch here and each minute we check how much it hurts?”

And so we drew this simple chart, and made recorded her scores.

The Foot Stinging Experiment
The initial observations from the Foot Spray Stinging Experiment

This was helpful for my daughter, my wife and I. It showed that although it felt very painful, the pain halved after the first minute and was gone completely in four minutes.

A problem was that we needed to keep using the spray twice a day. I decided to try to frame it as an experiment where we could test predictions.

“How stingy do you think it will be when we use the spray this evening?

“A 10 again”

It was a 9.

We kept doing this and chart below shows the results. Each time we used the spray the stinging was less and it stopped stinging quicker.  By the third day my daughter was actually eager to have the spray and was proud of the fact that she could show it no longer stung.

The Foot Stinging Experiment Results
The final results of the Foot Spray Stinging Experiment

This episode highlighted several points for me. The first is the value of jointly designing ways to test disagreements and gather more information. The second is that in situations of high emotions (or pain) there is value in having measures (even subjective ones like ‘stingingness’) to overcome cognitive biases (like magnifying recent events and incorrectly predicting the future). Although this is a personal example I think these benefits are applicable to a wider situation.




2 responses to “The Stinging Foot Spray Experiment: How data helps in emotional situations”

  1. John M. Greco Avatar

    Love this, Benjamin! What a great great example that everyone can surely relate to! Thanks for putting this out there …

  2. Guy Armitage Avatar

    Ben, I’m buying festival tickets as we speak, getting some spray and some graph paper…bring on the pain!

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