In his latest book Consciousness and the Social Brain Princeton neuroscientist Michael Graziano proposes a unique and compelling theory of consciousness. He proposes that the same circuits that the human brain uses to attribute awareness to others are used to model self-awareness. He emphasizes that his attention schema theory is only tentative, but it is testable and it does fit our current knowledge of brain function.
In a recent interview for the Brain Science Podcast (BSP 108), Graziano used the following clinical example to clarify his approach. A colleague had a patient who was convinced that he had a squirrel in his head. When confronted with the illogic of his claim the patient replied “Not everything can be explained by science.” In this example it is clear that the squirrel doesn’t really exist, so the question to be answered is HOW did his brain reach the conclusion that it does.
While imagining one has a squirrel in one’s head is thankfully rare, we also know that our subjective experiences of the world are not necessarily accurate. Our perception of the world is shaped by how our brain processes the sensory inputs it receives. For example, we perceive white light as an absence of color even though in reality it consists of all wavelengths.
Perception is something our brains do constantly and which we can not consciously control. In considering awareness (and by extension consciousness) perception-like Graziano is emphasizing several important features. The most important is probably the fact that it is only “quick and dirty model” of what is really going on, which means that our intuitions about consciousness are not necessarily reliable. In fact, humans have a strong tendency to over-attribute awareness to the world around us. This is part of the social circuitry that has made us the most successful species in the earth’s history, but it can also lead to amusing results (as anyone who has interacted with Siri on an iPhone has no doubt observed).
Another implication of considering awareness as a form of social perception is that it reverses the usual approach taken to understanding consciousness. Instead of asking how a physical brain can produce something subjective and non-physical called consciousness, we ask what kind of information processing leads to the conclusion that I (or anyone else) is conscious. As Graziano points out, this is a “mechanistic” model. Not only can it be tested but it has interesting implications. Dr. Graziano concluded that one of the key implications is "that awareness and consciousness are tools for information processing, and they are mechanistically understandable, and presumably can be engineered.”
I find the attention schema theory to be very compelling. Besides being testable, it has a simple elegance that I appreciate. It also explains why most humans experience a world filled with spirits, and are utterly convinced that their own consciousness is something special and non-physical.
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Since understanding consciousness is one of the deepest questions facing neuroscience, it has been explored on many previous episodes of the Brain Science Podcast. Rather than list all those episodes I want to mention just a few that I think are particularly relevant to this month’s episode.
In BSP 57 psychologist Chris Frith (Making up the Mind: How the Brain Creates Our Mental World) introduced the idea that our brain creates the world we experience, but that world is not necessarily an accurate representation of the physical world around us.
In BSP 67 philosopher Thomas Metzinger (The Ego Tunnel: The Science of the Mind and the Myth of the Self) considered how unusual experiences (like the out of body illusion) shed light on how our brains create the world we experience, including our experience of who we are.
Please post your comments about this episodes in the new thread on our Goodreads page at http://brainscienceforum.com.
Dr. Campbell will be speaking at The Amazing Meeting this July. This year's theme is skepticism and the brain.
Don't forget to check out listener John Richards new neuroscience glossary at http://richardsonthebrain.com.