Can quantum physics explain irrational decisions?

Thinking in a quantum-like way lets people confront complex questions

Ever wondered why people take irrational decisions? Some researchers have used a mathematical model to suggest that such human behaviour may not appear irrational when viewed in the context of quantum physics—a theory which propounds that particles and atoms have the ability to move simultaneously in many directions, and even spin clockwise and anti-clockwise at the same time.

“Our brain can’t store everything. We don’t always have clear attitudes about things. But when you ask me a question, like ‘What do you want for dinner?’, I have to think about it and come up with or construct a clear answer right there," said Zheng Joyce Wang, an associate professor of communication and director of the Communication and Psychophysiology Lab at the US’ Ohio State University, in a press statement. She calls this behaviour “quantum cognition".

In the 14 September press statement, Wang explains that whenever something comes up that isn’t consistent with classical theories, we often label it “irrational". But from the perspective of quantum cognition, some findings aren’t irrational any more but consistent with quantum theory—and with how people really behave.

The findings of Wang and her colleagues, which were published in two review papers in the journals Current Directions In Psychological Science and Trends in Cognitive Sciences suggest that thinking in a quantum-like way enables humans to make important decisions in the face of uncertainty, and allows us to confront complex questions despite our limited mental resources.

When researchers try to study human behaviour using only classical mathematical models of rationality, such aspects of human behaviour seem irrational, Wang explains.

Wang cites the example of Schrödinger’s cat—the thought experiment in which a cat inside a box has some probability of being alive or dead. Both possibilities have potential in our minds. In that sense, the cat has the potential to be perceived as dead or alive at the same time. The effect is called quantum superposition. But when we open the box, both possibilities are no longer superimposed, and the cat must be either alive or dead. With quantum cognition, it’s as if each decision we make is our own unique Schrödinger’s cat, according to Wang.

Wang took pains, though, to emphasize that her research programme neither assumes nor proposes that our brains are literally quantum computers.

But there have been attempts by other research groups to do so. In 1989, for instance, eminent English mathematician and cosmologist Roger Penrose published The Emperor’s New Mind: Concerning Computers, Minds And The Laws Of Physics, which, among other things, even suggested that consciousness had something to do with what he termed “quantum gravity". Penrose won the 1988 Wolf Prize for Physics, which he shared with theoretical physicist and cosmologist Stephen Hawking for their contribution to our understanding of the universe, and is the son of a psychiatrist and mathematician, Lionel Penrose.

There were critics of this theory, and Penrose did respond by writing two more books—Shadows Of The Mind: A Search For The Missing Science Of Consciousness in 1994 and The Large, The Small And The Human Mind in 1997. In those works, he included the observations of anaesthesiologist Stuart Hameroff and argued that consciousness is the result of quantum gravity effects in microtubules (small fibrous structures that give cells their structural support), which they christened Orch-OR—for Orchestrated Objective Reduction.

This concept also faced its share of criticism. In a 16 February 2005 paper, Canada’s University of Waterloo researchers, including Abninder Litta and Chris Eliasmith, said that attempts to explain brain function by appealing to quantum mechanics “is akin to explaining bird flight by appeal to atomic bonding characteristics". They insisted that while it was tempting to try and understand human thinking by drawing on analogies with contemporary technologies, “neurocomputational (referring to neurons in the brain) rather than quantum mechanisms provide the most credible explanations of mental phenomena".

While criticisms have since been traded back and forth on this subject, Hameroff and Penrose announced in January 2014 that a discovery of quantum vibrations in microtubules by Anirban Bandyopadhyay of the National Institute for Materials Science in Japan confirms the hypothesis of the Orch-OR theory. A reviewed and updated version of the theory was published along with critical commentary and debate in the March 2014 issue of Physics Of Life Reviews.

The debate on whether the brain is akin to a quantum computer, though, is unlikely to die down in a hurry. Besides, scientists are yet to fully establish the weirdness of quantum physics.

Cutting Edge is a monthly column that explores the melding of science and technology.

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