Two quantum physicists walk in and out of a bar

One of the great mysteries of the human mind is surely the pun. Just why are they funny? To explain it, researchers have proposed a new quantum theory of humour – work that could be in line for next year’s IgNobel prizes.

In the new work, published in Frontiers in Physics, Australian physicist Kirsty Kitto and Canadian psychologist Liane Gabora have applied the mathematics of quantum theory to puns.

Currently psychologists reckon the funniness of a pun is related to the little endorphin kick we experience when our brain switches from seeing one meaning to another, often a contradictory one. It’s a combination of surprise, juxtaposition, and perhaps a dash of vulgarity.

For example, consider: Time flies like an arrow. Fruit flies like a banana.

Here, during the set-up, we interpret the situation one way, and once the punch line comes, there is a shift in our understanding (oh, the insect likes bananas). That gets the laugh.

But scientists trying to express this cognitive processing in the form of an equation haven’t got very far. Instead, the authors of the new work argue that it is not the shift of meaning, but rather our ability to perceive both meanings simultaneously, that makes a pun funny. That’s where quantum theory comes in.

One of the central phenomena in quantum theory is superposition — where a particle can be in two states at once. That’s what led the Austrian physicist Erwin Schrödinger to come up with a scenario where a cat could be understood to be alive and dead at the same time.

Schrödinger and his colleagues developed the maths to deal with these conundrums a century ago. Now, Kitto and Gabora have done the same for the pun.

“Funniness is not a pre-existing ‘element of reality’ that can be measured,” says Gabora. “It emerges from an interaction between the underlying nature of the joke, the cognitive state of the listener, and other social and environmental factors. This makes the quantum formalism an excellent candidate for modelling humour.”

Let’s be clear: this is not related to pseudoscientific notions that the brain is a kind of quantum computer. The researchers aren’t suggesting any kind of quantum processing is going on when we hear a joke — just that the maths is similar.

In their paper the pair examines such classic puns as, Why was 6 afraid of 7? Because 789. They used quantum mechanics to describe the ‘superposition’ of the sound ‘eyt’: which can be heard as ‘eight’ and ‘ate’.

To test their ideas, they collected a bundle of jokes that did or did not contain such a superposition. Then they ran them past 85 Canadian undergrads — and (surprise, surprise) those jokes with simultaneous but contradictory meanings were the funniest, as they expected.

Some would say analysing a joke sucks the fun out of it. Be that as it may, the work does give us an insight into the weirdness of the universe. Our reality is built on microscopic dualities — states of being that should be incompatible and yet are not. Our universe, in a sense, is built from puns.

Whether you laugh or not is besides the point. The thing about quantum mechanics jokes is they can be incredibly funny and incredibly unfunny at the same time.