Denis Pombriant
6 min readJan 25, 2021

Maybe you’ve heard this one but read along because it has lessons for today.

Little Johnny has to do a project for school and, being a little boy, he decides to torture a frog in the name of science. He acquires a notebook, a sharp pencil, a knife, a measuring tape, and a frog. He also has the rudiments of the scientific method imperfectly acquired from class.


The experiment starts innocently enough. Johnny draws a line in the sand, places the frog behind it and the loudly stamps his foot just behind the frog. Startled, the animal jumps, and Johnny measures the distance recording in his notebook, “A frog with four legs jumps four feet.”

Good enough. Let’s call this the control part of the experiment.

Johnny then gets to work. He cuts off one of the frog’s legs and repeats the process, finally writing in his notebook, “A frog with 3 legs jumps 3 feet.”

That’s rather brutal but on the scale of things, many thousands of mice (and other animals) are routinely sacrificed annually in labs around the world. So, this experiment though conducted by an admittedly junior researcher should not be judged as unnecessarily cruel though subsequent events might give us all pause.

At any rate, Johnny cuts another leg off and repeats the experiment and writes in his notebook, “A frog with 2 legs jumps 2 feet.”

We know where this is going and subsequently our intrepid experimenter records the observation that a frog with one leg somehow jumps a whole foot.

Then the inevitable happens and he severs the last leg. The almost dead frog though wanting to get away from its tormentor does not have the ability and simply writhes on the ground as it expires. Little Johnny grabs his notebook and records that “A frog with no legs is deaf.”

When told well this joke gets a laugh because it follows many of the rules of comedy, especially creating cognitive dissonance. Most people hearing the joke for the first time laugh because they can’t fathom jumping from observations about the data, i.e. a frog with 4 legs jumps four feet, etc. and a conclusion from left field. How can cutting the legs off a frog affect its hearing? Can frogs even hear in the first place? Statisticians might feel better about the data if there were more data points…

Denis Pombriant

Researcher, author of multiple books including “The Age of Sustainability” about solutions for climate change. Technology, business, economics.