In quantum theory of cognition, memories are created by the act of remembering

March 17, 2014 by Lisa Zyga feature
Venn diagram showing the relationship between the assumptions of cognitive realism and cognitive completeness, and their overlap, which defines classical cognitive models. Quantum models satisfy cognitive completeness but not cognitive realism, and a model in the class ‘X’ would satisfy cognitive realism but not cognitive completeness. Credit: Yearsley and Pothos. ©2014 The Royal Society

( —The way that thoughts and memories arise from the physical material in our brains is one of the most complex questions in modern science. One important question in this area is how individual thoughts and memories change over time. The classical, intuitive view is that every thought, or "cognitive variable," that we've ever had can be assigned a specific, well-defined value at all times of our lives. But now psychologists are challenging that view by applying quantum probability theory to how memories change over time in our brains.

"There are two lines of thought when it comes to using quantum theory to describe ," James M. Yearsley, a researcher in the Department of Psychology at City University London, told "The first is that some decision-making processes appear quantum because there are physical processes in the brain (at the level of neurons, etc.) that are quantum. This is very controversial and is a position held by only a minority. The second line of thought is that basic physical processes in the brain at the level of neurons are classical, and the (apparent) non-classical features of some human decision-making arises because of the complex way in which thoughts and feelings are related to basic brain processes. This is by far the more common viewpoint, and is the one we personally subscribe to."

Memory construction

In their study, Yearsley and Emmanuel M. Pothos, also at City University London, have proposed that quantum probability theory may be used to assign probabilities to how precisely our thoughts, decisions, feelings, memories, and other cognitive variables can be recalled and defined over time. In this view, recalling a memory at one point in time interferes with how we remember perceiving that same memory in the past or how we will perceive it in the future, much in the way a measurement may change the outcome of something being measured. This act of recall is sometimes called "constructive" because it can change (or construct) the recalled thoughts. In this view, the memory itself is essentially created by the act of remembering.

As Yearsley explains, the idea that measurements might be constructive in cognition can be understood with an example of chocolate cravings.

"It's a little bit like how you can be sitting at your desk happily working away until one colleague announces that they are popping out to the shop and would you like anything, at which point you are overcome with a desire for a Twix!" he said. "That desire wasn't there before your colleague asked, it was created by that process of measurement. In quantum approaches to cognition, cognitive variables are represented in such a way that they don't really have values (only potentialities) until you measure them. That's a bit like saying as it gets towards lunchtime there is an increased potentiality for you to say you'd like a Twix if someone asks you, but if you're hard at work you might still not be thinking consciously about food. Of course, this analogy isn't perfect."

This quantum view of memory is related to the uncertainty principle in quantum mechanics, which places fundamental limits on how much knowledge we can gain about the world. When measuring certain kinds of unknown variables in physics, such as a particle's position and momentum, the more precisely one variable can be determined, the less precisely the other can be determined.

The same is true in the proposed quantum view of cognitive processes. In this case, thoughts are linked in our cognitive system over time, in much the same way that position and momentum are linked in physics. The cognitive version can be considered as a kind of entanglement in time. As a result, perfect knowledge of a cognitive variable at one point in time requires there to be some uncertainty about it at other times.

Overturning classical assumptions

The scientists explain that this proposal can be tested by performing experiments that try to violate the so-called temporal versions of the Bell inequalities. In physics, violation of the temporal Bell inequalities signifies the failure of classical physics to describe the physical world. In , the violations would signify the failure of classical models of cognition that make two seemingly intuitive assumptions: cognitive realism and cognitive completeness.

As the scientists explain, cognitive realism is the assumption that all of the decisions a person makes can be entirely determined by processes at the neurophysiological level (although identifying all of these processes would be extremely complicated). Cognitive completeness is the assumption that the of a person making a decision can be entirely determined by the probabilities of the outcomes of the decision. In other words, observing a person's behavior can allow an observer to fully determine that person's underlying cognitive state, without the need to invoke neurophysiological variables.

Neither of these assumptions is controversial; in fact, both are central to many kinds of cognitive models. A quantum model, however, does not rely on these assumptions.

"I think the greatest significance of this work is that it succeeds in taking the widely held belief that cognitive variables such as judgments or beliefs always have well-defined values and gives us a way to put that intuition to experimental test," Yearsley said. "Also, assuming we do find a violation of the temporal Bell inequalities experimentally, we would be ruling out not just a single model of cognition, but actually a very large class of models, so it's potentially a very powerful result."

Interpreting a possible violation of a temporal Bell inequality is not straightforward, since one would have to decide which of the two assumptions—realism or completeness—should be abandoned. The researchers argue that for the purposes of creating models of cognition it makes more sense to assume that cognitive realism is not valid, thus rejecting the idea that decisions can thought of as being be fully determined by underlying neurophysiological processes. A key implication would be that an individual may not have a well-defined judgment at all points in time, which may offer insight into aspects of cognition which have so far resisted formal explanation. One such example is the creation of false memories.

The scientists hope that future research will help clarify the role of quantum probability in cognitive modeling, and shed light on the complicated process that make up all of our memories, thoughts, and identities.

Explore further: Quantum communication scheme provides guaranteed security without quantum memories

More information: James M. Yearsley and Emmanuel M. Pothos. "Challenging the classical notion of time in cognition: a quantum perspective." Proceedings of The Royal Society B. DOI: 10.1098/rspb.2013.3056

Related Stories

Quantum Theory May Explain Wishful Thinking

April 14, 2009

( -- Humans don’t always make the most rational decisions. As studies have shown, even when logic and reasoning point in one direction, sometimes we chose the opposite route, motivated by personal bias or simply ...

Recommended for you

Probe for nanofibers has atom-scale sensitivity

January 20, 2017

Optical fibers are the backbone of modern communications, shuttling information from A to B through thin glass filaments as pulses of light. They are used extensively in telecommunications, allowing information to travel ...

Magnetic recording with light and no heat on garnet

January 19, 2017

A strong, short light pulse can record data on a magnetic layer of yttrium iron garnet doped with Co-ions. This was discovered by researchers from Radboud University in the Netherlands and Bialystok University in Poland. ...


Adjust slider to filter visible comments by rank

Display comments: newest first

Diogenes Tha Dogg
5 / 5 (4) Mar 17, 2014
Yeah yeah, we all learned from the Phaedo that our souls already know everything there is to know about the world, and we learn through recollection. I notice their paper doesn't even cite Plato once! I am SO done with this speculative "cognitive neuroscience" *exasperated sigh*
1 / 5 (5) Mar 17, 2014
Notwithstanding that physicist Philip Bucksbaum proved that an infinite amount of information can be stored on a single electron, the quantum processes that help us to store and reconstruct engrams are dependent upon the entire brain, as experimentation on subjects with serious brain injuries have revealed. Nevertheless, Bucksbaum's research does suggest that all the information encountered within the reach of a singular environment over time exists to be extrapolated by the intuitive mind since that information is modulated on all the particles that make up the medium.
Mar 17, 2014
This comment has been removed by a moderator.
1 / 5 (4) Mar 17, 2014
Step back, take a deep breath, and dismiss the nonsense of "memories are created by the act of remembering" as you read: Consciousness in the universe: A review of the 'Orch OR' theory


Intelligent comments on the article are also available for free.

We need only wait another 85 years for evolutionary theorists to apologize for bastardizing everything known about the conserved molecular mechanisms of cause and effect that link food odors and pheromones to classically-conditioned behaviors associated with experience-dependent receptor-mediated changes that must be initiated at the level of quantum physics (e.g., changes in base pairs) and be maintained by biophysical constraints that link species from microbes to man via ecological adaptations -- NOT VIA CONSTRAINT-BREAKING MUTATIONS or via memories created by remembering.
5 / 5 (2) Mar 17, 2014
From the abstract for the paper:

"We present a radical alternative, motivated by recent research using the mathematics from quantum theory for cognitive modelling. Such cognitive models raise the possibility that certain possibilities or events may be incompatible, so that perfect knowledge of one necessitates uncertainty for the others. In the context of time-dependence, in physics, this issue is explored with the so-called temporal Bell (TB) or Leggett–Garg inequalities. We consider in detail the theoretical and empirical challenges involved in exploring the TB inequalities in the context of cognitive systems."

This fallacy is called "False analogy." Just because you use *mathematics* from quantum physics to model cognition doesn't mean that the properties of quantum physics inhere in your model of cognition.

As much as the woo-meisters denigrate the reductive and materialist approach of modern science, they sure like to mimic the terminology of its technology.
4.7 / 5 (3) Mar 18, 2014
Call the shaded area of the Venn diagram above a Theseus ship.

The solution is:

Scientists discover that DNA damage occurs as part of normal brain activity.
The repair uses inversion of the segments replaced. The inversions are memory.

Check this when these segments are expressed before and after inversions.
The expressions will differ. Don't believe me, carry out this research and test.


5 / 5 (3) Mar 18, 2014
Quantum Physics is characterized by probability. The converse is not true, i.e. a system characterized by probability is quantum.

The unique thing about QM is that there isn't hidden variables underlying the statistics. In the brain, there are lots of underlying variables, the electro-chemistry of the neurons, etc. The probabilistic nature of decision making can be explained by an enormous number of hidden variable models. I don't understand how they can apply Bell's inequalities to prove there are no hidden variables, when there are. I would question the results of the experiment if it showed there are no hidden variables to brain decision statistics.
5 / 5 (1) Mar 19, 2014
The 2 "non-controversial assumptions": Cognitive realism ?= there is a possible 1:1 mapping b/w mental concepts and neural level, i.e., reduction? Who believes that? In my experience, most psychologists are rather instrumentalists about such concepts. Even behaviorism is more meaningful than this quantum thing - desires are dispositions, no "real stuff".

Cognitive completeness ?= The whole internal cognitive state can be inferred from behavior? Who believes that? Not even "behaviorists" like G.Ryle.

"I think the greatest significance of this work is that it succeeds in taking the widely held belief that cognitive variables such as judgments or beliefs always have well-defined values" - Widely held by whom? Perhaps there are few cognitive essentialists and platonic realists, but you don't need QM to see it's wrong.

What does the quantum approach contribute, except for fancy sounding analogies and metaphors for things we already understand?
(Disclaimer: cannot access the orig.paper)
5 / 5 (1) Mar 19, 2014
I don't understand how they can apply Bell's inequalities to prove there are no hidden variables, when there are.

Then you should read up on what the Bell inequalities are.

Just because you use *mathematics* from quantum physics to model cognition doesn't mean that the properties of quantum physics inhere in your model of cognition.

That's what the Bell inequalities are supposed to test.

If there are local hidden variables, you can perform certain experiments involving quantum properties where the result would satisfy a Bell inequality. If it doesn't, then it shows that no locally realistic hidden variable theory can explain what is happening with the system.

To get around that, you have to abandon either realism or localism (completeness), which means arguing that your mental state is fundamentally indetermined, or that your mental state is encoded at least in part somewhere outside of your person!
not rated yet Mar 19, 2014
The third way to get around a violation of a Bell inequality is to argue that the system is non-free or completely determined by a non-causal process.

A non-free entity in this sense is like a book or a video. All the possible states already exist, and are simply unfolded by time. This is called superdeterminism.
1 / 5 (1) Mar 19, 2014

Physically basic physical processes in the brain at the level of neurons are not classical, otherwise our world would not be quantum, and since Planck in 1900, a classical world cannot exist, because of infinite energy for the black-body radiation, in a classical world.
Thus this type of study asking if our brain is classical or quantum, is out of the reality, and more related to the historical difficulty of our brain to accept that the quantum reality of our world is different from the classical feeling that we have in our day life.
The simplest is to accept the quantum equations that describe very accurately the real experiments, without any ad hoc hypothesis, like Born quantum wave collapse, never clearly observed and put in the quantum equations. First Everett has proposed this simple solution with the splitting of our world in many parallel worlds at each quadecoherence
1 / 5 (1) Mar 19, 2014
Everett splitting in parallel worlds at each quantum decoherence, is what we use in the quantum equations to describe our real world.
In theses calculations, from the past, we sum on all the parallel paths, fluctuations, possibilities, i;e. intermediate parallel worlds, to reach the real measurement, otherwise, the calculations do not agree with the real experimental results.
Why not accept, the same, for the future as we make for the past : the future is made of all the paths, possibilities, i.e. of all the parallel world splitting by decoherence of the actual quantum world ?
It is disturbing to think that, in the future, we have sosies living all the possible different lifes in parallel worlds, but it is no more than to observe that the actual reality is made of all past parallel paths to the actual world, with us.
5 / 5 (1) Mar 20, 2014
"The cognitive version can be considered as a kind of entanglement in time"

"quantum probability theory"

to the writier of this article. Please before letting your finger touch the keyborad and write down this nosense, go home and take some good lessons about QM!

not rated yet Mar 23, 2014

these forums get weirder by the day...
Whydening Gyre
not rated yet Mar 23, 2014
Concepts are formed by the act of conceptualizing (Sarcasm intended).
not rated yet Mar 24, 2014
If memories are formed by the act of remembering and concepts by the act of conceptualizing, does it follow that notions are generated by the act of notionalizing? Just kidding, but if any reader ever wondered what the light at the end of the quantum tunnel looks like, there are rumours that make it comparable to fireflies, going on-and-off in totally unpredictable ways regarding position and frequency.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.