Chater is a professor of Behavioural Science at Warwick Business School. His book seeks to explode the myth of the unconscious mind. He suggests that humans do not have thoughts below the mind’s surface waiting to bubble up. Humans “generate our beliefs, values, and actions in-the-moment; they are not pre-calculated and ‘written’ in some unimaginably vast memory store just in case they might be needed…. Introspection is a process not of perception but of invention: the real-time generation of interpretations and explanations to make sense of our own words and actions.” Chater suggests that we know less than we think we know. Therefore, we make up explanations ex post and ad hoc. If we are asked to explain how a bicycle, a zipper, or a thermostat work, most humans find that they only have an illusory conception of the details. This improvisational quality to explanations is referred to as ‘the illusion of explanatory depth’, which is the “contrast between our feeling of understanding and our inability to produce cogent explanations.”
The mind is not a mirror onto the world. It does not store a picture of all its surroundings to be summoned up at will. Instead, when taking in a scene from the outside world, “the brain ‘grasps’ different aspects of the image at different times…. Our brain glimpses, and conceives of, the world fragment by fragment.” Our field of vision is actually quite narrow with our peripheral vision exceedingly blurry. Also, studies have shown that our eyes can take in only one color at a time, before rapidly moving on to the next color in the field. This lack of perceptual depth is true even with mental images. “Our imagination, like visual experience, is a narrow window of lucidity, and what we see through that window is invented — creatively, subtly, intelligently — not merely reported from some fully specified, entirely coherent inner world.” When we are asked to imagine the image of a tiger or a cube upon a table most often we forget to include details such as the direction of the tiger’s stripes or the shadow the cube creates on the surface, until later asked about them when we quickly fill those into our previous mental picture. “We are not examining a fully formed, comprehensively detailed and coloured mental image in our mind’s eye — at one moment zooming in, or shifting our attention to the left and right. We are, instead, creating our mental image, piece by piece, moment by moment, touchpoint by touchpoint.” This is why our dream world seems so disjointed. “Dreams seem to be naturally viewed as the successive creation and dissolution of momentary fragments; in retrospect full of holes and contradictions…. Scenes and even time itself shifts abruptly, people change identities, and appear and disappear without warning…. There is no careful author painstakingly attempting to bring the story into some kind of order — merely a succession of capricious imaginative leaps…. We haven’t forgotten these details; our brain never bothered to specify them in the first place…. Dreams are improvised stories, with few details sketched in. When our minds create them, we lock onto some specific fragments of information; almost everything else is left entirely blank.” This is the same with our daytime thoughts. “Our thoughts are not shadows of an alternative inner reality, to be charted and discovered; they are fictions of our own devising, created moment by moment.”
The brain also invents feelings and emotions based on external clues, sensory inputs, and our own interoceptive system. “The brain interprets each piece of perceptual input (each face, object, symbol, or whatever it may be) to make as much sense as possible in the light of the wider context.” The background details of a photograph will widely change how we interpret the emotions on the photo’s face close-up. Context fuels the imagination. Often, even our own emotion is cued by external context. In psychological experiments, a shot of adrenaline induced either anger or euphoria depending on the external stimuli in the room. “It seems that we are figuring out what emotion we must be experiencing, and doing so, in part, from the state of our own body. We tend to imagine that our emotions well up from within, and cause physiological reaction…. But in reality it seems that we are figuring out what emotion we must be feeling, partly based on observing our own physiological state.” We interpret our interoceptive system based on external clues and then latch onto the emotion that best fits the combined situation. “Having an emotion at all is a paradigmatic act of interpretation, and hence of reasoning.”
The brain’s capacity is constrained by its neural networks. Chater suggests that each interconnected group of neurons can only interact with a single problem at a time. “The brain works by cooperative computation across most or all of its neurons — and cooperative computation can only lock onto, and solve, one problem at a time…. The unconscious cannot be working away on, say, tricky intellectual or creative challenges, while we are consciously attending to some other task — because the brain circuits that would be needed for such sophisticated unconscious thoughts are ‘blocked’ by the conscious brain processes of the moment…. Consciousness, and indeed the entire activity of thought, appears to be guided, sequentially, through the narrow bottleneck: sub-cortical structures search for, and coordinate, patterns in sensory input, memory and motor output, one at a time. The brain’s task is, moment by moment, to link together different pieces of information, and to integrate and act on them right away.” The brain processes the vast amounts of incoming sensory data, but then quickly focuses its attention, discarding all that is irrelevant. “Our brains lock onto fragments of sensory information, and work to impose meaning on those fragments. But we can only lock onto and impose meaning on one set of fragments at a time…. The brain will initially find some basic ‘meaning’ to help pin down which information is relevant and which is not…. As the brain’s processing step proceeds, the effort of interpretation will narrow ever more precisely on the scraps of information that helped form whatever pattern is of interest, and the processing of other scraps of information will be reduced and, indeed, abandoned.”
The brain is so interconnected that it can, most often, only do one thing well at a time. “People could do two things at once when distinct mental calculations — presumably associated with non-overlapping networks of neurons — were involved (e.g. for sight-reading music and taking dictation). And such specialized brain networks can sometimes be developed for highly practised and repetitive tasks.” Even when walking and thinking, people tend to slow their pace when a challenging or novel thought enters their brain. Chater suggests that unconscious thought is a complete myth. The brain is never working away on problems in the background for them only to flash into consciousness when fully formed and worked out. “There is absolutely no sign that we can search for xs when we are currently thinking about ys, or search for ys, when we have been thinking about xs. As soon as we switch from searching one category to searching another, all search processes for that first category appear to cease abruptly.”
Importantly, Chater suggests that there is a neural background that does form an unconscious, but it is not comprehensible, even to our own minds. “The neural processes within each cycle of thought are, crucially, not the kind of thing that could be conscious. They are, after all, hugely complex patterns of cooperative neural activity, searching for possible meanings in the current sensory input by reference to our capacious memories of past experience. But we are only ever conscious of particular interpretations of current sensory input…. We are conscious of, and could only ever be conscious of, the meanings, patterns and interpretations that are the output of this cooperative computation…. Our conscious experience is determined by what the brain thinks is present — the output of the cycle of thought, not its input.” This flow between the brain and sensory input is a two way street that results in predictive processing where some inputs are neglected by neural predictions, which highlight only the relevant information. “Perception, then, is a process of incredibly rich and subtle inference — the brain is carefully piecing together the best story it can about how the world might be, to explain the agitations of its sense organs. Indeed, attempts to interpret sensory input, language or our own memories typically involve inference of great subtlety to figure out which ‘story’ weaves together the data most compellingly…. Perception requires puzzling out the significance of a set of clues, each of which has little significance when considered in isolation.” Therefore, “mental processes are always unconscious — consciousness reports answers, but not their origins.” The brain was constructed, evolutionarily, to relay back to its owner the world as it really is, not the plethora of its inputs how they come in. “In order to decide how to act, we need to know what the world is like; our brains don’t care about the complex process of gathering and knitting together our stable world…. Our sense that seeing and hearing seem continuous arises because the brain is informing us that the visual and auditory worlds are continuous; and subjective experience reflects the world around us, not the operations of our own minds.” There is nothing more withheld within our brains than our own consciousness. “Our conscious experience consists of organizations of the surface of our sensory experience, whether conjured up through perception, imagination, or memory…. We consciously experience the sensory information, broadly construed (including images generated by our own minds; sensations from inside our bodies, such as pain, feelings of exhaustion or hunger; and crucially from inner speech).”
The brain uses past memories to interpret present perceptions. “We layer each momentary thought on top of past momentary thoughts, tracing an ever-richer web of connections across our mental surface…. The interpretation of each everyday scene depends on a vast hoard of past interpretations of everyday scenes. Indeed, perception works by relating, often in the most flexible and creative fashion, our sensory input with our memory of past experience. We do not interpret every sensory impression afresh, but in terms of the memory traces of past sensory impressions.” Importantly, memory stores past interpretations of inputs, not the raw inputs. Therefore, the past that was not deemed necessary to be interpreted is also not remembered. “Today’s memories are yesterday’s perceptual interpretations.” This creates a continuity of thought within the brain. “Our mental life follows channels carved by our previous thoughts, and traces of our present thoughts and actions will shape how we think and act in the future…. We do, after all, possess some inner mental landscape. But this is not an inner copy of the outer world or, for that matter, a library of beliefs, motives, hopes or fears; it is, instead, a record of the impact of past cycles of thought.”
Metaphor is critical for our interpretation of the world. “Our continual search for meaning is the struggle to find patterns in our present experience, in the light of the past. And so we see one thing in terms of another…. Metaphors, too, are also employed to impose meaning upon one aspect of the world, by drawing on an understanding of another.” It is not that the brain does not have unconscious processes, it is simply that they cannot be accessed to become conscious. There is not a vast store of mental thoughts bubbling below the surface. There are only the inchoate inputs from which the brain creates the only thoughts that it has at all- conscious experience.
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