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After a few years of driving, you are able to hold conversations while navigating a busy city. How is this possible without unconscious thought?Photograph by wavebreakmedia / Shutterstock

Nick Chater has put forward a bold claim in his recent book, The Mind Is Flat, as well as in an article and interview in Nautilus: that we don’t have any unconscious thoughts. A metaphor that Chater, a behavioral scientist, dislikes is that of the iceberg, the tip of which is our consciousness, and the vast, submerged part is our unconscious. As Chater says in the Nautilus interview, this suggests that unconscious and conscious processes use the same kinds of representations, and that the kinds of things we are unconscious of we could be conscious of.

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He’s certainly right that many brain processes go on that we’re unaware of, and can’t be aware of. Let’s take visual recognition as an example. We can recognize that something is an image of an animal with astounding speed. We can even do this with cartoon animals. Chater says, “With each thought, you’re taking up massive fragments of information and trying to pull them together.” But we’re not aware of how these fragments work together to constitute dogness. So how does Chater say that all thought is conscious? By tailoring the definition of “thought” to suit his conclusion.

Mental health psychology uses the term for things like “unwanted thoughts,” and here is where Chater’s argument is strongest. But in cognitive psychology and cognitive science, “thought” isn’t really a technical term. We kind of know what it means, but in general, cognitive psychologists and cognitive scientists don’t use the term “thought” to represent any key concept in their theories and explanations. If Chater were to start using more technical terms, he’d find himself in much deeper water. He might even see more of the iceberg.

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Let’s take a term that is fairly technical in cognitive psychology: memory. There is no doubt that all of us have memories that we are never conscious of. The most uncontroversial example is what is known as “procedural memory”: the memory of how to do things. Your ability to ride a bike involves memories encoded and layed down during a long learning process. These memories are accessed and exploited whenever you ride a bike. When you learned how to ride, something changed in your brain, and whatever those changes are we call memories.

Importantly, we are largely unconscious of the memories we use to we ride a bike. In fact, we are often wrong when we try to describe how we do physical activities. For example, when you want to turn right on a bike, you often actually steer left slightly first, which causes your bike to tilt right. But most people not only don’t know that they’re doing this, but they don’t believe you when you tell them!

We can only be conscious of a few things at once.

One thing that is well known in psychology is that practice results in “automatization.” This means that the activity becomes faster and less conscious. The first time you try to drive a car, it is experienced as a bewildering confusion of pedals, the steering wheel, and too many things to pay attention to. But after a few years of driving, you are able to hold conversations while navigating a busy city. How is this possible without unconscious thought?

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Chater might say that your procedural memories of how to drive aren’t “thoughts.” But he also says that unconscious things are things that cannot be conscious. When you’re learning to drive, everything is conscious, and the limits of your attention and consciousness is what makes it so hard. You can only drive safely when you’ve automatized, and made unconscious, much of what you have to do. So here we seem to have an example of a conscious thing becoming unconscious. Were they thoughts when you were conscious of them, but then ceased to be thoughts once they were learned?

Perhaps. There is a large scientific literature showing that our opinions of how we move are counter to how we actually move, including crawling and catching fly balls in baseball. In my own laboratory, my student Jay Jennings ran an experiment that showed that while people (wrongly) believe that a ball spiraling within a tube will continue to spiral once it emerges, their hands move to the right place when they go to catch the ball.

When there is a conscious, explicit memory that is in conflict with an unconscious memory, we have clear examples that some memories are unconscious. So Chater can’t say that all “memories” are conscious. Well, what about facts? What cognitive scientists call “declarative memories” are fact-like beliefs about the world, like your belief that peanut butter is brown. Are all declarative memories conscious?

In one sense, certainly not, because you are not conscious of all of your memories all the time. We’ve all had the experience of being asked something, and responding with something like “I haven’t thought about that in years.” This means that you have memories that you had not been retrieving lately. The stored memories you are not retrieving are still memories, yet you are not (currently) conscious of them.

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In Chater’s own experiment, he had people retrieve in memory as many foods as they could. People quickly ran out of ideas, meaning that new ideas came more and more slowly. Let’s say it takes someone two minutes to finally come up with eggplant. They were not conscious of the thought that eggplant was a food until two minutes into the task. So what was the nature of their belief that “eggplant is a food” before conscious retrieval? I’d say it was an unretrieved declarative memory. What would Chater say? He’d have to say that it wasn’t a thought until it was conscious.

But here we run into his problem with the iceberg: If the unconscious is made up of fundamentally different kinds of representations from the representations of conscious thought, then you should not be able to bring to mind thoughts that aren’t already conscious. So Chater would have to say that your memory that eggplant is a food is an unconscious something-or-other that only becomes a “thought” after it’s retrieved. But even that still feels to me like you can retrieve an unconscious belief into consciousness.

This does not seem to square with his statement that we have no unconscious beliefs (in his book he claims, “The inner, mental world, and the beliefs, motives, and fears it is supposed to contain is, itself, a work of the imagination.”) Perhaps Chater thinks of a “thought” as something being used in some kind of thinking process, and unaccessed memories don’t count. In some of his examples, he talks about how your mind isn’t solving problems unconsciously. So do we ever process unconscious memories?

When you’re driving, you’re using automatized, unconscious processes to do much of the work. It’s common to have driven home and have no memory of the drive, because your mind was elsewhere. There is a vast amount of visual processing that goes into driving, and this is largely unconscious.

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So let’s assume that Pat is thinking about what to make for dinner while driving home. She approaches a red light, and will pass through the intersection when the light turns green. She has a choice of two lanes. In the leftmost lane sits a car with a left-turn signal on. Pat enters the right lane. It is likely that some part of her mind saw the turn signal, inferred that it was deliberate, that the driver wants to turn left, that turning left at an intersection often takes time because of oncoming traffic, and that if she were to get behind this car, it would make her trip longer. Some part of her mind concludes that being in the right lane is better.

Now, even if Pat were giving all of her attention to this driving situation, rather than dinner, it is very unlikely that all of these thoughts would consciously go through her head. And yet the conclusion is drawn, and the action is taken. The idea that the thoughts involved in this inference consciously go through Pat’s head while she’s planning dinner is absurd. We can only be conscious of a few things at once.

However, it’s also true that if she had reason to, she could very well attend to these unconscious perceptions. Suppose she suddenly recognized the car as belonging to her friend. She might immediately be aware of the turn signal, and try to guess where her friend might be going. If there is an unconscious thing that can become conscious, then Chater’s view of the iceberg is flawed, because for this to happen there must be some unconscious memories that can become conscious, which means that they are represented in the same form.

So it appears we have lots of unconscious declarative memories that seem to be processed unconsciously. If we try to cast Chater’s claims about “thoughts” into the more technical term “memory,” his claim is much less convincing.

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Jim Davies is a professor at the Institute of Cognitive Science at Carleton University in Ottawa, and author of Riveted: The Science of Why Jokes Make Us Laugh, Movies Make Us Cry, and Religion Makes Us Feel One with the Universe. His sister is novelist JD Spero.

WATCH: The mind is a book that can be opened and read, if you know the language in which it’s written.

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