Quantum theory may only explain the world at subatomic scales, but the mathematics behind it may have even broader applications. How we perceive the world may be shockingly similar to some of the weirdest quantum phenomena.

That's the argument put forward by an article from *New Scientist*, which points to how human thought processes can work in ways that defy classical logic but make perfect sense from a quantum perspective. For example, there's the famous double-slit experiment, in which photons are sent one at a time through a pair of parallel slits A and B.

In the classical world, you could close slit B and send all the particles through slit A, creating a dispersal pattern, and then repeat the process by opening slit B and closing slit A. Then, when you open *both* slits, you'd expect the dispersal patterns to simply be the sum of these two patterns. But this is the quantum world we're talking about, and the two patterns actually *interfere* with each other, and this holds true even if you send one particle through the slits at a time. This is one of the most basic proofs that photons and other quantum objects are both particles and waves, something that would be quite impossible in the classical world.

So what does all that have to do with how we think? Writing for *New Scientist*, Mark Buchanan explains:

In the early 1990s, for example, psychologists Amos Tversky and Eldar Shafir of Princeton University tested the idea in a simple gambling experiment. Players were told they had an even chance of winning $200 or losing $100, and were then asked to choose whether or not to play the same gamble a second time. When told they had won the first gamble (situation A), 69 per cent of the participants chose to play again. If told they had lost (situation B), only 59 per cent wanted to play again. That's not surprising. But when they were not told the outcome of the first gamble (situation A or B), only 36 per cent wanted to play again.

Classical logic would demand that the third probability equal the average of the first two, yet it doesn't. As in the double slit experiment, the simultaneous presence of two parts, A and B, seems to lead to some kind of weird interference that spoils classical probabilities.

That's just the beginning of this cognitive spin on quantum weirdness. Check out the full article for a lot more.

*Double-slit experiment image by **Timm Weltkamp**.*