How Consciousness Might Have Evolved

Human consciousness. Our mad, prodigious mind. Our personhood. Where did consciousness come from? How did it become part of us? How did it become 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 signals carrying data about where the edges of objects are  located come in 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 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!” Feeling this cerebral glow, we easily believe we carry an ethereal self, even an undying soul. But I think it’s the opposite conclusion that is exciting: that the splendor of consciousness is not that is an outlier in nature but that it is a thoroughly earthly step in the series of small, pragmatic adjustments that is evolution.


Four Modes of Everyday Consciousness

The gear shift on our car labels the modes of the transmission: Park, Reverse, Neutral, Drive and maybe Sport. Our consciousness has a few basic settings of its own, though they are not so clearly labeled and we often shift from one to another without knowing it. But trying to describe them has heightened my appreciation of them. Here are the ones that I come up with when I’m awake.

The first is Awareness. This unfocused, nonverbal state seems to consist of plain sensory input with little or no processing beyond a sense of recognizing familiar items. It is the state of my consciousness when I’m idly watching a man ride a bike down the street, when I watch a movie, when I’m relaxing or tired. It includes familiar actions like lifting a fork or saying “Hi. How are you?” Awareness feels passive but also primed for response.

Stream of Consciousness, Gary Buhler (

Stream of Consciousness, by Gary Buhler

Like Awareness, Stream of Consciousness also seems undirected, spontaneous. But there the resemblance ends. This state consists of words, images, and sounds flowing or tumbling around with little connection to where I am or what I’m doing. Sometimes this flow gets noisy and intrusive, a kaleidoscope with little or no focus. It includes vivid flashbacks and anxious glimpses of the future. But mostly, in my head, it consists of words, a sort of thinking-lite. And quick. An instant from a minute ago: “Pomodoro Seinfeld Columbus reservation not on Tuesday Bill’s trip 70th street.” Thinking-very-lite.

Third, after Awareness and Stream of Consciousness, there’s Attention. Attention is similar to mindfulness, but mindfulness seems to be a meditative goal while Attention in one form or another is the state that our mind is in whenever we are concentrating on something. It is focused, often wordless, and sometimes relaxed. It is the “flow” state we enjoy when we are fully immersed in dancing, painting, writing, jogging. Or when we are observing a bird closely or, fleetingly, when we take a picture. To me, Attention has the quality of stepping closer to something and experiencing it with clarity and pleasure.

Finally, there’s Language. When we are thinking, talking, listening, reading, writing, Language is not only on our mind. It is also the mode of our mind. My wife and I discuss plans for the day, I think about a blog post, I try to make a point in a conversation, and I read apps in search of news that is new. What’s odd about Language in contrast to the sense of closeness that sometimes comes with Attention is that I sometimes experience  Language consciousness as a slight stepping away from or around something. This is difficult to explain. The advantage of Language is that it connects us with others. The disadvantage is that the symbols and rules that we play by to say what we mean and connect with others  are not the thing itself.

So these are the states that I most often catch my conscious mind in the midst of: Awareness, Stream of Consciousness, Attention, and Language. Among these four there are many variations depending on what the brain needs to get done, different levels of quiet and frenzy, focus and randomness, articulation and muteness, closeness and distancing.

This post is over. Time to shift gears. You too.