How Consciousness Might Have Evolved

Human consciousness. Our wonderful, crazy mind. Our personhood. And our quandary. Where did consciousness come from? How did it become part of us?

Michael Graziano, a neuropsychologist I’ve posted about before, writes in the June 2016 Atlantic about how consciousness might have evolved. He starts with the question that evolutionists ask about any feature of an organism: What is its adaptive value?

The answer, he writes, is that consciousness is a sophisticated solution to a difficulty that plagues the nervous system of all creatures: “Too much information constantly flows in to be fully processed.” It’s an old dilemma, with early fixes. Even before the formation of brains, nervous systems 600 million years ago enhanced certain nerve signals at the expense of others. The eyes of insects and crabs, for example, generate “an outline sketch of the world” as the signals carrying visual data about the edges of objects are stronger than other visual signals.

Then around 500 million years ago, a controller in the early brains of fish and reptiles began coordinating several senses at a time, “aiming the satellite dishes of the eyes, ears, and nose towards anything important.” The controller did so by generating an internal model, a set of information about the current state of the body parts, and predicting “how these body parts will move next and about the consequences of their movement.” If you had only a reptilian controller for a brain, you would look at the steps in front of you and the controller would check those nerve signals against its model of where your legs ought to be to get you up the steps successfully.

But we have much more than a controller. Some mammals, including us, have the latest upgrade, the cerebral cortex. We can pay attention to something we are not even focused on at the moment—the TV in the other room, for instance—because our cortex can select what to select. What’s more, we can even be self-aware that we are doing so. “I’m not going to go in there, but he’s watching that news again” (my example). Humans can do this because our upgraded controller uses schemas, models of not only all that we know but also of our attention itself. Our brain tracks “what covert attention is doing moment by moment and what its consequences are.” This is where we get that self-aware voice inside us that tells us, “I’ve got something intangible inside me. It moves around from one thing to another and allows me to understand and remember.”

Such evolution of consciousness goes hand in hand with our social evolution, according to Graziano. Animals acquired the capacity to be aware of the mind of other members of their species. Social awareness and self-awareness have evolved “in tandem….We understand other people by projecting ourselves onto them. But we also understand ourselves by considering the way other people might see us.” Consciousness tracks and grows from our social life and our social self.

Graziano acknowledges that the schema theory of consciousness is still new, but he believes it “provides a general framework” for understanding consciousness and its evolution. It seems to me that it does so very well. It’s difficult for us to see our minds in physical terms because we have that voice in our head that insists, “Wow! I’m thinking and feeling all this!” Glowing with this cerebral radiance, we easily believe we carry an ethereal self, even an undying soul. But it is thrilling to me to understand the splendor of consciousness not as an outlier in nature but as a thoroughly earthly step in the push of small, accidental, pragmatic adjustments that is physical life.


Steven Pinker on Emotions and Genes

Steven Pinker’s How the Mind Works might well be subtitled “And the emotions too.” It’s one terrific book. It offers a barrage of insights and connections about humans and evolution that can feel intoxicating. It stirs up the nature-nurture controversy with a blender. It does not see you as you almost certainly see yourself. And it is often very funny.

Despite the book’s title, Pinker talks more about emotions than about the mind itself. He sees them working together. The mind, he says, is computational: it processes information. Much of this information comes from the body’s biological systems. Emotions are units, modules, that use this bodily information to take direct steps—fear, anger, hunger, lust, egotism, empathy—that will promote survival and reproduction.

Humans, Pinker writes, are not, as we often believe, divided into thoughts and feelings that work against each other.

The emotions are adaptations, well-engineered software modules that work in harmony with the intellect and are indispensable to the functioning of the whole mind. The problem with the emotions is not that they are untamed forces or vestiges of our animal past; it is that they were designed to propagate copies of the genes that built them rather than to promote happiness, wisdom, or moral values. We often call an act ‘emotional’ when it is harmful to the social group, damaging to the actor’s happiness in the long run, uncontrollable and impervious to persuasion, or a product of self-delusion. Sad to say, these outcomes are not malfunctions but precisely what we would expect from well-engineered emotions. (Kindle location 7688)

So the good news is that our seemingly perverse emotional moments do not mean that something is wrong with us. But the not-so-good news is that our emotional acts are more deeply engrained in us than our well-meaning searches for happiness, wisdom, and virtue.

So are we doomed by the genes that build these emotional responses, responses that often mean we get  carried away just when we want to stay cool and collected? Pinker addresses this issue often, here in a discussion of love:

The confusion comes from thinking of people’s genes as their true self, and the motives of their genes as their deepest, truest, unconscious motives. From there it’s easy to draw the cynical and incorrect moral that all love is hypocritical. That confuses the real motives of the person with the metaphorical motives of the genes. Genes are not puppetmasters; they acted as the recipe for making the brain and body and then got out of the way. (8342)

I like the recipe metaphor. As I take it, genes are like the list of the ingredients and the steps for making a cake, but the flavor and texture of the cake itself is quite different from that sheet of instructions.

A human

A human “cake” and his genetic “recipe”

But if the genes have built emotions to keep us alive, doesn’t that mean those emotions are quite inflexible? Yes and no. Our own emotional core might not change much in our life time, but in species-time, the story is different.

Might the software for the emotions be burned so deeply into the brain that organisms are condemned to feel as their remote ancestors did? The evidence says no; the emotions are easy to reprogram. Emotional repertoires vary wildly among animals depending on their species, sex, and age. Within the mammals we find the lion and lamb. Even within dogs (a single species) a few millennia of selective breeding have given us pit bulls and Saint Bernards. (7721)

Pinker, in conclusion, tells us about ourselves in ways we may have difficulty recognizing. Modules and systems fine-tuned to an ancient past may seem non-human and even anti-human. But it’s not so difficult to absorb how science depicts the machinery of our emotions at the same time that we are inquiring thoughtfully about the meanings of our lives. Or, to put it another way, we can come to understand our recipe while we ponder what it is like to be the cake.

For more on the man, the book, and the debate, here is a lively and helpful article.

Steven Pinker on Disgust, Sex, and Happiness

Hearts and brains. Mind and body. We are quite sure that our thoughts take place in our heads. But what about our emotions? Sometimes we locate them in our hearts, sometimes vaguely in our bodies.

But Stephen Pinker in his terrific 1997 book How the Mind Works explains that most of our moods and bodily reactions take place in the mind. He describes them as “modules” in a computer-like brain, sensation-generating programs that have evolved to keep us alive and reproducing. Here I’ll highlight a few of Pinker’s explanations of emotions and sensations that are anchored fully and partly in, and maybe beyond, our brains.

Disgust and Sex Two strong emotions, disgust and lust, are fully the products of evolution going back millions of years.

“Disgust is a universal human emotion” (Kindle location 7865), Pinker writes. Its universality is a sign of how thoroughly we are programmed to resist eating animal parts that might contain infectious microorganisms or other toxins. Humans are disgusted by the smell, the sight, or the even idea of eating most animals and animal parts. “The nondisgusting animal parts are the exception. …Many Americans eat only the skeletal muscle of cattle, chicken, swine, and a few fish” (7903). Every other animal is a source of contamination. We won’t drink a beverage stirred with a flyswatter, even if the flyswatter is brand new. We “find a sterilized cockroach every bit as revolting as one fresh from the cupboard.…People won’t eat soup if it is served in a brand-new bedpan….You can’t pay most people to eat fudge baked in the shape of dog feces.”

Such reactions make no rational sense. With rare exceptions, food today is safe. But just try to eat soup from a new bedpan and feel how loudly your bad-food alarm starts blaring, still set to several million years ago.

Changing the locks. (

Changing the locks.

As for sex, we think we know exactly what its purpose is, one that we share with almost all living things. But here’s Pinker.

Why is there sex to begin with?…Why don’t women give virgin birth to daughters who are clones of themselves instead of wasting half their pregnancies on sons who lack the machinery to make grandchildren and are nothing but sperm donors? Why do people and other organisms swap out half their genes for the genes of another member of the species, generating variety in their offspring for variety’s sake? It’s not to evolve faster, because organisms are selected for fitness in the present. It’s not to adapt to environmental change, because a random change in an already adapted organism is more likely to be for the worse than for the better….The best theory…is that sex is a defense against parasites and pathogens (disease-causing microorganisms). …[Your body’s defenses against germs evolve, but the germ’s tricks for evading those defenses evolve much faster.] Sexual reproduction is a way of changing the locks once a generation. By swapping half the genes out for a different half, an organism gives its offspring a head start in the race against local germs. (9577)

To most people, the evolutionary function of disgust makes some sense. But the idea that sex too plays a role in our resisting disease boggles the mind. The sensation itself is no reliable guide to its evolutionary function, according to Pinker.

Happiness Another important emotional experience has thin roots in evolution but has held a place in human culture and vocabulary for at least a couple of thousand years. But it too, understood scientifically, is not what we expect. This is happiness.

Happy moment (

Happy moment

Pinker writes that it might seem at first that happiness serves as an incentive to spur us on towards those conditions that are biologically good for us. These conditions include being “healthy, well-fed, comfortable, safe, prosperous, knowledgeable, respected, non-celibate, and loved” (8097). Set these as your steps towards happiness and you will become an evolutionarily successful human specimen. This certainly has been my own view of the adaptive function of happiness.

The trouble, Pinker points out, is that happiness doesn’t actually continue for the period of time during which we are enjoying any of these cheerful states. In fact, the longer that any condition persists without change, whether it is illness or health, modest income or prosperity, celibacy or marriage, the more likely we are to drift toward a middling, default attitude that we describe as feeling “content” or “satisfied.”

In reality, we usually describe ourselves as “happy” at those times when we succeed in achieving more than we already have (as the result, for example, of a professional reward) or when we find out that we are a little better off in some way than those around us. Happiness, it seems, is rooted in comparison and newness. For Pinker, this makes it a rather dismal treadmill, an elusive, fleeting, bubbly emotion that was never cut out to serve as the goal for one’s entire life.

Self, Consciousness, and Free Will Finally, in the last pages of his book, Pinker writes about some philosophical puzzles that people have never been able to wrap their minds around fully. These are such phenomena as the self (the “I” that we are so aware of), consciousness (our awareness, and our awareness of our awareness) and free will (we insist that our choices and decisions are up to us).

Too much for the computational mind to handle. Edvard Munch's The Scream (

Too much for the computational mind to handle. Edvard Munch’s “The Scream”

For Pinker the reason these are such enigmas may be simply that “the mind of Homo sapiens lacks the cognitive equipment to solve them. …Our minds evolved by natural selection to solve problems that were life-and-death matters to our ancestors, not to commune with correctness or to answer any question we are capable of asking” (11570). Such mysteries as the self and free will are holistic phenomena of a kind that does not lend itself to being understood by “the computational apparatus that natural selection has fitted us with” (11639), an apparatus that works methodically from parts to the whole, example to category, cause to effect. Perhaps such a mind just cannot analyze such sensations as the experience of  being alive and being ourselves.

In summary, for Pinker, emotions and sensations are not matters of the heart. Their roots lie in the evolution of the brain, the interaction of brain and culture, and a holistic awareness beyond the brain itself.