Sitting on the Marine Atlantic ferry, I’m watching the Newfoundland skyline disappear on the horizon as I type away. I see the rocking of the ocean waves, inhale its salty breeze, feel and hear the buzz of the ship’s rumbling engine. I try to focus on writing this sentence, but my eyes hopefully scan the ocean for a rogue, splashing whale.
According to a new paper in Cognitive and Behavioral Neurology, these sights, smells, and glances are mere memories, even as I feel that they’re happening in real time. A team from Boston laid out a new theory of consciousness that inextricably ties it to memory.
In a nutshell: at its core, consciousness evolved as a memory system. It helps us remember the events of our lives—the whens, wheres, whats, and whos—which in turn can help us creatively and flexibly recombine them to predict or imagine alternative possibilities.
It gets more mind-bending. Rather than perceiving the world in real time, we’re actually experiencing a memory of that perception. That is, our unconscious minds filter and process the world under the hood, and often make split-second decisions. When we become aware of those perceptions and decisions—that is, once they’ve risen to the level of consciousness—we’re actually experiencing “memories of those unconscious decisions and actions,” the authors explained.
In other words, it’s mainly the unconscious mind at the wheel.
Thanks to the massively parallel computing power in biological neural networks—or neural circuits—much of the brain’s processing of our surroundings and internal feelings happens without our awareness. Consciousness, in turn, acts as a part of our memory to help tie events together into a coherent, serial narrative that flows with time—rather than snippets from a disjointed dream.
“Our theory is that consciousness developed as a memory system that is used by our unconscious brain to help us flexibly and creatively imagine the future and plan accordingly,” said author Dr. Andrew Budson. “We don’t perceive the world, make decisions, or perform actions directly. Instead, we do all these things unconsciously and then—about half a second later—consciously remember doing them.”
For now, the theory is just that—a theory. But viewing consciousness through the lens of a memory system could provide new clues to brain disorders, such as stroke, epilepsy, dementia, and others that impair memory or consciousness. The theory also raises questions about animal, AI, and mini-brain consciousness, helping neuroscientists further probe how the conscious and unconscious brain work together every second of our lives.
How Am I Aware?
Consciousness has tickled the brains of our greatest thinkers for thousands of years. Why did it develop? What is it good for? How did it emerge? And why is dampening urges (like that second serving of incredibly crispy off-the-boat fish and chips) so hard to resist?
And what exactly is consciousness?
It’s a bit bewildering that we don’t yet have a settled definition. Broadly speaking, consciousness is a personal experience of the world, including our own existence. Mainly conceived of back in the 1890s, this broad sketch of the concept leaves plenty of room for multiple theories.
Two ideas rule in neuroscience, with global efforts to battle it out through carefully designed experiments. One is the global neuronal workspace theory (GNWT), which posits that the brain integrates information from multiple sources into a single data “sketch” on a “global workspace.” This workspace, having knowledge of only items in our attention, forms a conscious experience.
In contrast, the other mainstream theory, Integrated Information Theory (IIT), takes a more connective view. Here, consciousness arises from the neural architecture and interconnectedness of brain networks. The physical and data processing properties of neural networks—particularly, the rear regions of the brain—by themselves can generate consciousness.
Other theories dig deep into the complex web of neural connections, suggesting that information loops between brain regions, extended in time and space, generate consciousness. Some suggest that an awareness of “self” is critical to being conscious of the outside world.
Yup, it’s a zoo of theories out there.
A Dash of Memory
The new theory took inspiration from previous ideas and experimental data, coming to a surprising conclusion: that consciousness evolved as part of memory—in fact, it is the process of remembering.
Scientists have long linked consciousness to episodic memory, a “journal” of our lives encoded by the hippocampus. Intuitively it makes sense: what we consciously experience is essential for forming “life” memories, which associates different aspects of an event in time. But here, the authors argue that consciousness works hand in hand with the brain’s memory networks, together forming a “conscious memory system” that gives rise to consciousness.
The team began with a troubling thought: that conscious perception is incredibly slow, and often fools us. Take various auditory or visual illusions—the dress, anyone?—it’s clear that our conscious perception is influenced by far more than reality itself. So why do we value consciousness as a way to perceive, interpret, and interact with the world?
The answer, suggest the authors, is memory. Consciousness may have evolved together with memory so we can remember. Say you’re walking around a familiar neighborhood and hear a bark. In milliseconds, the bark zaps to our working memory—a mental “sketchpad” to process data. There, it acts as a cue to retrieve a previous memory of the same bark, and the face of an overzealous puppy eager to nip ankles. Upon remembering, you quickly cross the street.
Here, consciousness is absolutely integral for the entire sequence. Hearing the bark—that is, consciously perceiving it—draws memories to consciously remember. The brain then imagines what could happen (another nip?), causing you to dash away. Without the conscious perception of the bark, we wouldn’t link it to potential danger or make an effort to circumvent it.
Ok, so what?
The crux, the authors explain, is that consciousness, as a critical part of memory, can help to flexibly and creatively combine memory to plan future actions. Or in their words, “there is no reason that consciousness needs to operate in real time.”
This means that rather than experiencing the world in real time, we may be perceiving our surroundings and internal thoughts as “memories”—like seeing a night sky full of stars that may no longer, in reality, be there. It further allows us to project into the future or reach into the depths of creativity and imagination, sketching new worlds based on memory, but with new ways of combining those elements.
The brain is famous for its parallel processing capabilities, and much of that happens under the hood. A consciousness memory system makes sense of disjointed unconscious information, time-stamping each bit so that the recollections roll like a movie.
“Even our thoughts are not generally under our conscious control. This lack of control is why we may have difficulty stopping a stream of thoughts running through our head as we’re trying to go to sleep, and also why mindfulness is hard,” said Dr. Budson.
By reframing consciousness as part of memory, the team hopes the theory can help patients with neurological disorders. People with stroke that affects the cortex or surrounding neural highways often have an impaired ability to use memories to solve problems or plan for the future. Those with dementia, migraines, or epilepsy similarly have disturbances that cause disruptions in consciousness and memory, with the two often linked.
The authors are well aware that they’re stepping into controversial grounds. “Many—perhaps even most—of the hypotheses that we are proposing may turn out to be incorrect,” they wrote. Even so, testing the theory experimentally can “bring us closer to understanding the fundamental nature and anatomical basis of consciousness.”
Image Credit: Greyson Joralemon / Unsplash