Friday, September 18, 2015

Quantum Cognition?

A lot of researchers and experts in other fields have tried to use various principles in physics in their own field. Economics have tried to invent something called Econophysics, to varying degree of success. And certainly many aspects of biology are starting to incorporate quantum effects.

Quantum mechanics has been used notoriously in many areas, including crackpottish application by the likes of Deepak Chopra etc. without really understanding the underlying physics. I don't know if this falls under the same category, but the news report out of The Atlantic doesn't do it any favor. I'm reading this article on quantum cognition, in which human behavior, and certain unpredictability and irrationality of human behavior, may be attributed to quantum effects!

Now, the reason why I don't think this article is that good is because it makes a number of either misleading, or strange errors.

Take, for example, the classic prisoner’s dilemma. Two criminals are offered the opportunity to rat each other out. If one rats, and the other doesn’t, the snitch goes free while the other serves a three-year sentence. If they both rat, they each get two years. If neither rats, they each get one year. If players always behaved in their own self-interest, they’d always rat. But research has shown that people often choose to cooperate.

Classical probability can’t explain this. If the first player knew for sure that the second was cooperating, it would make most sense to defect. If the first knew for sure that the second was defecting, it would also make most sense to defect. Since no matter what the other player is doing, it’s best to defect, then the first player should logically defect no matter what.

A quantum explanation for why player one might cooperate anyway would be that when one player is uncertain about what the other is doing, it’s like a Schrödinger’s cat situation. The other player has the potential to be cooperating and the potential to be defecting, at the same time, in the first player’s mind. Each of these possibilities is like a thought wave, Wang says. And as waves of all kinds (light, sound, water) are wont to do, they can interfere with each other. Depending on how they line up, the can cancel each other out to make a smaller wave, or build on each other to make a bigger one. If “the other guy’s going to cooperate” thought wave gets strengthened in a player’s mind, he might choose to cooperate too.

So you tell me if that made any sense or if this person has actually understood QM beyond what he read in a pop-science book. First of all, when wave cancellation occurs, it doesn't "make a smaller wave". It makes NO wave at that instant and time. Secondly, this person is espousing the existence of some kind of a "thought wave" that hasn't been verified, and somehow, the thought waves from the two different prisoners overlap each other (this, BTW, can be described via classical wave pictures, so why quantum picture in invoked here?).

But the fallacy comes in the claim that there is no other way to explain why different people act differently here without invoking quantum effects. Unlike physics systems where we can prepare two systems identically, we can find no such thing in human beings (even  with twins!). Two different people have different backgrounds and "baggage". We have different ethics, moral standards, etc. You'll never find two identical systems to test this out. That's why we have 9 judges on the US Supreme Court, and they can have wildly differing opinions on the identical issue! So why can't they use this to explain why people react differently under this same situation? Why can't they find the answer via the human psychology rather than invoking QM?

But it gets worse...

The act of answering a question can move people from wave to particle, from uncertainty to certainty. In quantum physics, the “observer effect” refers to how measuring the state of a particle can change the very state you’re trying to measure. In a similar way, asking someone a question about the state of her mind could very well change it. For example, if I’m telling a friend about a performance review I have coming up, and I’m not sure how I feel about it, if she asks me “Are you nervous?” that might get me thinking about all the reasons I should be nervous. I might not have been nervous before she asked me, but after the question, my answer might become, “Well, I am now!”

Of course, this smacks of the crackpottery done in "The Secret". Let's get this straight first of all, especially those who do not have a formal education in QM. There is no such thing as "wave-particle duality" in QM! QM/QFT etc. describe the system via a single, consistent formulation. We don't switch gears going from "wave" to "particle" and back to "wave" to describe things things. So the system doesn't move "from wave to particle", etc. It is the nature of the outcome that most people consider to be "wave-like" or "particle-like", but these are ALL produced by the same, single, consistent description!

The problem I have with this, and many other areas that tried to incorporate QM, is that they often start with the effects, and then say something like "Oh, it looks very much like a quantum effect". This is fine if there is an underlying, rigorous mathematical description, but often, there isn't! You cannot says that an idea is "complimentary" to another idea the same way position and momentum observables are non-commuting. The latter has a very set of rigorous mathematical rules and description. To argue that "... quantum models were able to predict order effects shown in 70 different national surveys... " is not very convincing because in physics, this would be quite unconvincing. It means that there are other factors that come in that are not predictable and can't be accounted for. What is there to argue that these other factors are also responsible for the outcome?

Again, the inability to test this out using identical systems makes it very difficult to be convincing. Human behavior can be irrational and unpredictable. That is know. Rather than considering this to be the result of quantum effects, why not consider this to be the result of a chaotic behavior over time, i.e. all of the various life experiences that an individual had all conspire to trigger the decision that he/she makes at a particular time. The "butterfly effect" in an individual's time line can easily cause a particular behavior at another time. To me, this is as valid of an explanation as any.

And that explanation is purely classical!


1 comment:

Jose Acacio de Barros said...

As a physicist by training, I can relate to your skepticism. After all, there is lots of nonsense being said about QM (and who can't find funny the text of the Ig Nobel Prize given to Deepak Chopra?).

However, it should be pointed out that most people in the area of quantum cognition do not use anymore the literal view that there is something quantum about cognition. Instead, the most currently accepted view is that the partial order measures given by quantum probabilities are good descriptors when classical probability theory fails. This is simply because social systems, like quantum systems, are contextual. So, when describing social systems, how do we deal with such contextuality, since classical probability theory usually cannot (at least in a straightforward application)? The proponents of quantum cognition suggest borrowing the mathematics of QM, since physicists already figured out how to do this contextual modeling for quantum systems. If you look at the papers in the field, they are very rigorous mathematically, and there are lots of smart people working on this area.

Also, it is always important to remember that mathematical techniques are not only within the purview of physics. There are many disciplines that use them, and often there is lots of cross-pollination. The question here is not whether the mathematics of QM can be useful to other fields, but why it is useful, and whether it is too limiting.