In a further attempt to demystify consciousness, Michael Graziano proposes in an Atlantic piece that perhaps the odd phenomenon of phantom limbs can crack the hard problem. The sensation of lost legs and arms stems, it would seem, from the brain creating a “body schema” which persists unchanged (wrongly) after the loss. For whatever reason, the old template has remained, sometimes taking longer to recalibrate and occasionally never successfully doing so.

In his “Attention Schema Theory,” Graziano suggests that awareness is similarly driven by a model that anticipates sensation in an imprecise but effective way. I would think a “consciousness model” would have to know a whole other magnitude of complexity beyond one controlling a thumb or forefinger, but that certainly is possible. It would also explain why we’re so prone to fooling ourselves, how we can hole up in inside a certain worldview that’s been repeatedly reinforced, even if it runs counter to common sense and copious evidence.

An excerpt:

After studying the body schema for many years, I became interested in how the brain models another part of the self. Not a physical part like an arm, but a computational part. If the brain describes the physical body in ghostly, incomplete terms, how much more mystically would it describe a non-physical trait like computation?

One of the most crucial computational processes in the brain is attention. The word “attention” has many colloquial connotations, but in neuroscience it has a specific meaning. Attention is the selective enhancement of some signals over others, such that the brain’s resources are strategically deployed. In some ways attention is like a computational hand—it’s how the brain grasps things.

The brain needs to control its attention, just as it controls the body. To understand how, we can gain some insight from control theory, a well-developed branch of engineering theory that deals in the optimal ways for complex systems to work—whether those systems dictate the airflow in a building, traffic patterns in a city, or a robot arm. In control theory, if a machine is to control something optimally, it needs a working model of whatever it’s controlling. The brain certainly follows this principle in controlling the body. That’s why it computes a body schema. Since the brain can control its attention exquisitely well, it almost certainly has an attention schema, a simulation of its own attention.•