Let’s belatedly kick-off the new year with predictions. No, not about what the time ahead will bring about, but how our brain’s ubiquitous predictions are central to who we are.
Sean Carroll’s Mindscape podcast is part of my standard podcast listening regime. Lately, he interviewed Lisa Feldman Barret. This discussion is worth listening for anyone with only a faint interest in how our brain works, in particular also related to emotions.
Ms Barret has written an utterly interesting book, How Emotions Are Made: The Secret Life of the Brain. I couldn’t stop reading. Let me tell you why. I will only scratch the surface.
I have described here how our perception of reality is based on on-going simulations of the future, that is, predictions. Ms Barret confirms this flatly, it’s common neuro-scientific know-how these days. All our brain regions, or networks, predict, tirelessly, and use the signals from our senses to update these predictions as required, thusly balancing out prediction errors. In fact, our brains don’t even have the processing capacity to perceive the world anew at every moment, ie. from raw sensor data, if you will. It would also be a waste of resources. From an evolutionary point of view, a purely reactive brain would be very uneconomical, that is, too expensive, metabolically speaking. In order to get a clear picture purely on the visual input signals from the retina alone would require many, many more neural cells and interconnections than the brain can maintain, given its size, and how much energy it can consume. Our brain already consumes about 20% of our energy. It’s better to rely on the past, predict the future thereupon using already “pre-processed” patterns, and just correct using the noisy signals from the retina – with these corrections happening in the known context set up by the predictions. Way less processing-intensive. Pretty smart, if you think about it.
Of course, we do not normally consciously experience these predictions in our daily lives. Predictions are not of the sort of “what will happen tomorrow?”, but are in the millisecond range of the future. If we take vision, predictions are not some “picture” apart from what we “actually see”, and compared, and corrected. Predictions work directly on the same brain regions as our senses do: you see the prediction. In fact, you never see the raw reality, you always see the predictions corrected by reality. The number of signal inputs from the retina into our visual cortex is only about 10% of all inputs. The other 90% come from other brain regions as predictions. And about the same number of signals go from the visual cortex to other brain regions as predictions.
From a survival point of view, if you think about our evolution, it’s important to understand that the predictions inject contextualised meaning, not raw data. Predictions are based on our past experiences, which have created, and then continuously maintain and adapt in the course of our lives, the concepts of what we think as usual objects, such as a house, or a tree, or a tiger, but also immaterial objects such as family, or joy, or pain. So all our regions of our brains are brimming with predictions based on these concepts, all the time – even while sleeping, think of dreams –, and the predictions that most likely apply to the current situation (context) will “win”, and become your perceptions, ever changing. If the “wrong” prediction wins, we can perceive things that are not actually there, or we miss things that are.
Our brains have not evolved to enjoy a good book. Our brain’s basic and most important purpose is to keep us alive. That is, to keep our body’s multitude of physical parameters within viable boundaries (allostasis), and to keep us out of external harm’s way, such as from predators, or poisonous food, or our boss. The continuously predicting, reality-interpreting, and situationally goal-driven simulation and thus predictions is evolution’s economical and balanced solution. As mentioned above, a purely reactive brain would be way worse for the job: too slow, too big, too energy-intensive.
For our brain, locked up in our skulls, the rest of our body is as external as the outside world. Just as visual signals, our brain gets the status of our body via noisy signals from our organs: the interoceptive network. And the interoceptive network does as all brain regions do: it predicts. Namely, it predicts the needs of the different organs, in particular their energy needs. We have only so much energy available at any point, hence the interoceptive network must continuously balance all needs, keep what Ms Barret calls the body budget balanced, ie. try to make the right mix of predictions to keep us alive with the available resources. The interoceptive network makes predictions for sights, sounds, smells, touches, thoughts, memories, imagination, and emotions.
Ms Barret credibly debunks the still widely held, and decades old, belief that emotions, and the bodily expression thereof, are universal across all humans on the globe. She systematically deconstructs the experiments that have resulted in this theory, and demonstrates through more carefully conceived experiments that emotions and their expressions are actually acquired as any other concept, and can differ widely among the global population.
In particular there are no specific “fear circuits” or “anger circuits” or the like in our brains, which simply react in ways predefined and wired by evolution. They just cannot be found. The theory that our emotions are hard-wired in an older layer of our brain, the limbic system, and are “kept in check” by an evolutionary younger layer, the “rational” neo-cortex, does not hold up any longer under close scrutiny. Neuroscientists understand this today, but the message hasn’t trickled down to many psychologists, psychiatrists, sociologists, economists, and writers of self-help books. There’s no on-going “struggle” between the rational and a purely reactive emotional brain. All parts of the brain continuously predict, and the predictions that are probably the most suitable for the current situation – goals, dangers, … – will be what we perceive, and act upon.
Different emotions have a very wide range of bodily expressions. Just the other day, talking to a friend, I expressed something painful, and I smiled. She asked me, Why do you smile? People might misunderstand you! Yes, true, people with a superficial and stereotypical view of other’s emotions might do so, but then again, forcing a smile was my way of coping with the pain. Facial expressions, or any other emotional bodily reaction, are not universal, neither across cultures, nor across different people, and not even for the same person in different situations.
Ms Barret’s research results indicate that emotions are concepts that we learn as we grow up. Across cultures, they can be quite variant, and some types of emotions are not even known in different cultures. Also, in the west, we usually think of emotions as bound to a person. But in other cultures, emotions can only appear between people, that is, upon their interactions.
The thusly learned concepts, encoded as everything else in our brains as neural patterns, are then later instantiated situationally, based on the current goals, and the so called affective niche, ie. the focus of our attention. Emotions are not caused by some low level reactive brain circuits, and “overwhelm” us if we cannot “control” them, but are created via predictions, and prediction errors, which are our brain’s mechanism to keep us alive. Thusly created emotions continuously form the background, or basis, of our actions, thoughts, memories – who we are.
So called affects are our basic feelings, from pleasant to unpleasant in one dimension (valence), and from low to high arousal in the other, and are indicators of impacts on your body budget. When we acquire emotion concepts, the affects are encoded and, by repetition, reinforced as emotion concepts over the years, and the encoding includes the situational context. This gives us an arsenal, or vocabulary, of different emotion concepts, upon which we call when instantiation is needed, that is, basically all the time. A wider vocabulary enables us to act and react in more subtle, or differentiated, ways to our daily life situations and challenges. A limited or distorted vocabulary of available emotion concepts limits or distorts our abilities to cope with life.
Predictions and Prediction Errors
Predictions and prediction errors usually are in a healthy balance. Predictions make our perceptions, and thus lives, more stable, integrating over time, if you will. They are based on the past – with the past ranging from milliseconds to years back. On the other hand, prediction errors, ie. the difference between the prediction and what our noisy sensory networks read, signify a new, unknown situation, with the potential to form new concepts, or modify the existing ones, but also signalling alert.
If we had reduced capacities to detect prediction errors, we would perceive the world only based on predictions, without the corrective influence by prediction errors. We would potentially live in an unreal world. Think of dreams, which are purely prediction-based. Or hallucinations, people seeing “ghosts”. We can see whatever we want, if prediction errors are not corrected. If we didn’t have predictions, on the other hand, we would live highly alerted in a world full of uncertainty and continuous anxiety, heavily driven by prediction errors. Each and every sensory input would be such an error, absent any predictions.
Predictions probably even drive your motor actions. The brain always strives to reduce, or zero out, prediction errors. Upon a prediction error, there are two possibilities. Either the prediction is corrected to fit reality, or reality is acted upon to fit the prediction. So if you want to move an object to a different place, your brain makes this prediction, and your motor neurons initiate and control your actions to move it, resulting in zero prediction error. I am simplifying here, but you get the idea. Situational goal-orientation all the way down. No, not turtles.
I find the fact that we actually only ever perceive our predictions fascinating. It explains so much. It’s not a new theory and insight by any means. I heard it the first time from Anil Seth years ago. But I never made the leap to include emotions as well. We all know from daily life that you and I can, and often will, experience the same situation pretty differently. Different predictions, different emotion concepts as learned in life, different goal-based instantiations of these concepts in the moment.
The eternal “fight” between the irrational emotions and reason, with reason holding the animalistic emotions in check, never made a lot of sense to me. Now I understand why. Emotions are the substrate for all we think and do, and they are heavily driven by the state of our body, which our ever-predicting brain strives to keep well and alive. Emotions are not “hard-wired” in “older parts” of our brains, no such brain areas can be identified. Emotions are instantiated situationally, in a goal-oriented fashion, and within our current affective niche, based on emotion concepts that we have learned, and adapt and extend through all our lives. Emotion concepts are mainly created by culture and society, which includes family of course.
The same affects from our bodies – ie. the same interoception signals, or basic feelings – can result in many different ways our emotion concepts are instantiated. There is a study from Israel which shows that parole judges were way harsher in their parole decisions just before lunch, and they went back to their normal, average judgements after lunch. That is, the unpleasant “hungry” affects were instantiated as negative emotions towards, and thus perceptions of, the parolees, because the judicial judgements were within the the affective niche and goals. There are other examples of this kind in the book.
Also forget about universal bodily expression of emotions, across all people, societies, and cultures. A smile can have many pretty divergent causes or meanings. Pain can be pleasurable if you’re so inclined, resulting in a vastly different bodily expression than if pain is, well, painful to you. Trying to assess people’s state of mind based on the classic stereotypes can be highly misleading. I speak from experience, often being judged wrongly by people who don’t know me. I guess I am weird. Or at least not fitting the stereotypical common expectations. In the same vein, considering that we all see are our predictions, not reality, it’s easily understandable that we all perceive, and thus live, the same daily situations very differently.
In non-dual meditation you learn to realise that everything you perceive “is made of consciousness”, without any centre or “perceiver”. Sounds, breath, heartbeat, surroundings, thoughts, everything is just there, in a uniform space of equally valid perceptions. Now, if you think about predictions, and that we perceive our predictions, you realise: yes, exactly, everything in our reality is made of consciousness.