Quantum math makes human irrationality more sensible
Science News said:People often say that quantum physics is weird because it doesn’t seem rational. But of course, if you think about it, quantum physics is actually perfectly rational, if you understand the math. It’s people who typically seem irrational.
In fact, some psychologists have spent their careers making fun of people for irrational choices when presented with artificial situations amenable to statistical analysis. Making allowances for sometimes shaky methodology, there really are cases where people make choices that don’t seem to make much sense. One well-known example involved asking students whether they would buy a ticket for a Hawaii vacation in three different situations: They had passed a big test, they had failed the test, or they didn’t yet know whether they had passed or failed. More than half said they would buy the ticket if they had passed. Even more said they would buy the ticket if they failed. But 30 percent said they wouldn’t buy a ticket until they found out whether they had passed or failed.
It seems odd that people would decide to buy right away if they knew the outcome of the test, no matter what it was, but hesitated when the outcome was unknown. Such behavior violated a statistical maxim known as the “sure thing principle.” Basically, it says that if you prefer X if A is true, and you prefer X if A isn’t true, then you should prefer X whether A is true or not. So it shouldn’t matter whether you know if A is true. That seems logical, but it’s not always how people behave.
So are people just incapable of thinking logically? Maybe. But in recent years a number of investigators have developed the view that those supposedly irrational choices merely reflect the fact that people’s brains are guided by the mathematical principles of quantum physics.
These researchers are not saying that the brain is a quantum computer, exploiting actual quantum weirdness for thinking and reasoning. They’re just saying that the quantum mathematics describing physical processes operating in the natural world is the same as the math describing the cognitive processes operating in the brain.
“Twenty years ago, a group of physicists and psychologists introduced the bold idea of applying the abstract principles from quantum theory outside of physics to the field of human judgment and decision making,” Jerome Busemeyer of Indiana University and collaborators write in a recent paper on arXiv.org. “This new field, called quantum cognition, has proved to be able to account for puzzling behavioral phenomena that are found in studies of a variety of human judgments and decisions.”
Violation of the sure thing principle, for instance, can be explained using quantum math, as Jose Acacio de Barros of San Francisco State University and Gary Oas of Stanford show in another recent paper on arXiv.org. Whether to buy the ticket to Hawaii or not can be viewed as a double-slit quantum interference experiment, where an electron passes through a screen with two slits in it and lands on a detector surface. If one of the slits is closed (corresponding to pass or fail on the test), the electron behaves like a particle and lands at a precise spot on the screen. If the two slits are open (you don’t know the test outcome) the electron behaves like a wave, making it impossible to say which slit the electron actually passed through (corresponding to not knowing the test outcome). The electron wave interferes with itself, changing the probabilities of where it will land on the screen. A quantum mechanical analysis shows that those quantum probabilities violate the sure thing principle predictions, just as the psychology students did.
Various other supposedly irrational decision making practices and poor probability judgments have been analyzed using aspects of quantum math. “Quantum models of judgment and decision have made impressive progress organizing and accounting for a wide range of puzzling findings using a common set of principles,” Busemeyer and colleagues write.
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