Budson’s Consciousness as a Memory System

Neurologist and cognitive neuroscientist Andrew Budson and colleagues propose that consciousness evolved as part of the episodic memory system, likely to enable a flexible recombining of information, and it was subsequently co-opted to produce other functions, such as problem-solving, abstract thinking, and language. The theory challenges traditional views that consciousness is a mechanism for perceiving the immediate present or making real-time decisions, that consciousness evolved first for contemporary perception/action, and that episodic memory later stored those conscious contents.

Instead, Budson and colleagues argue that consciousness is essentially the “write” function of our episodic memory system; episodic memory required a conscious system to create and retrieve explicit event memories in the first place. They suggest that “there is no such thing as a conscious perception of the present moment.” They believe that “consciousness is the memory system” and argue that “consciousness was developed to allow us to perform the flexible, adaptive, and creative behaviors that characterize human life” (Budson et al., 2022).

Evolutionary Function of Consciousness

Budson and colleagues propose that the evolutionary function of consciousness is to aggregate sensory, semantic, and emotional information into a coherent narrative (a memory), which can then be retrieved to predict the future and plan complex behaviors. On the evolutionary purpose: “We posit that consciousness originally developed as part of the episodic memory system—quite likely the storage part of that system—allowing for the flexible recombination of information to simulate future possibilities.”

Hippocampal-based episodic circuits, together with distributed cerebrocortical systems (visual, auditory, semantic, etc.), constitute the physical substrate of conscious content (Budson et al., 2022).

Temporal Latency and Future Simulation

There are three key components of the theory.

1. The brain processes sensory information too slowly for consciousness to be involved in real-time actions. For example, by the time you become consciously aware of a sensory event (like a mosquito landing on your face), your motor systems have likely already reacted (swatting it away). Therefore, consciousness cannot be the driver of immediate action, which means that we do not perceive the present moment in real-time. What we experience as “consciousness” is actually a memory of the world as it was a few hundred milliseconds ago. “We perceive the world as a memory… experiencing a memory of a perception.” This is meant literally: the unconscious brain does the fast parallel processing; consciousness is the remembered, explicit rendering of selected results.
2. Since consciousness is too slow for the present, Budson argues it is for the future in that the brain evolved to predict outcomes. To be this kind of effective “simulation engine,” it needs a flexible database of past events. Thus, consciousness is the system that binds disparate sensory inputs (e.g., sight, sound, touch) and internal states (e.g., desire, hope, anxiety, fear) into a single “episode” that can be stored. This stored episode can be “replayed” later to simulate future scenarios.
3. The theory calls upon neuroscientific evidence showing that the same brain networks (including the hippocampus and the default mode network) are active when we remember the past and when we imagine the future, unifying memory and imagination. In other words, we use the same neural mechanisms to “see” what happened yesterday as we do to “see” what might happen tomorrow. Consciousness is the stage on which this oscillating mental time travel plays out.

As Budson and colleagues put it, “If we believe that episodic memory evolved solely to accurately represent past events, it seems like a terrible system—prone to forgetting and false memories. However, if we believe that episodic memory developed to flexibly and creatively combine and rearrange memories of prior events in order to plan for the future, then it is quite a good system.”

On the “latency” of awareness: “Our thoughts, sensations, and perceptions—what we experience as consciousness—are actually the content of our episodic memory system… We are not perceiving the world in real time; we are remembering it” (Budson et al., 2022).

Implications and Disorders of Consciousness

They suggest that their theory of “Consciousness as a Memory System” is compatible with many phenomena, particularly the slow speed and the after-the-fact order of consciousness, that cannot be explained well by other theories. Moreover, they believe that their theory “may have profound implications for understanding intentional action and consciousness in general.”

They suggest that “episodic memory and its associated memory systems of sensory, working, and semantic memory as a whole ought to be considered together as the conscious memory system in that they, together, give rise to the phenomenon of consciousness.” Lastly, because consciousness is identical with explicit memory, the neural correlates of consciousness should be the neural correlates of explicit memory. Thus, “the cerebral cortex is the part of the brain that makes consciousness possible, and that every cortical region contributes to this conscious memory system” (Budson et al., 2022).

Budson and colleagues claim that their theory may provide new answers to perennial questions, such as: Why did consciousness develop? What is consciousness good for? If consciousness developed to help us plan and act for the future, why is consciousness so difficult to control? Why is mindfulness so hard? And for that matter, if our actions are under our conscious control, why is dieting (and resisting other urges) so difficult for most of us?

Why does it appear that we are observers, peering out through our eyes at the world while sitting in the proverbial Cartesian theater? Why do we speak, in William James’s words, of a “stream of consciousness”? Can we perform complicated activities (such as driving) without being consciously aware of it? Are animals conscious (and if so, which ones)? Are there developmental, neurologic, or psychiatric disorders that are actually disorders of consciousness?

On disorders of consciousness, they conclude: “If consciousness is a memory system, then disorders of memory should be disorders of consciousness. We believe that they are. Patients with Alzheimer’s disease, for example, often lose the ability to plan for the future, to solve problems, and to think abstractly” (Budson et al., 2022).