Tuesday, July 29, 2014

A intriguing take on consciousness as a perceptual construct.

A recent review by Aaron Schurger in Science Magazine pointed me to Michael Graziano's 2013 book "Consciousness and the Social Brain", which I immediately downloaded, read, and abstracted. Very engaging and clear writing (although I am dumbfounded that he makes no reference to Thomas Metzinger's work and 'ego tunnel' model, which has common elements with his own.) In Graziano's theory awareness is information, the brain's simplified, schematic model of the complicated, data-handling process of attention. A brain can use the construct of awareness to model its own attentional state or to model someone else’s attentional state. An extract from Schurger's review:
In Consciousness and the Social Brain, Michael Graziano argues that consciousness is a perceptual construct—the brain attributes it to other people in much the same way that the brain attributes speech to the ventriloquist's puppet. To clarify, imagine being greeted by a very lifelike android version of your best friend with a prerecorded behavioral program that had you genuinely fooled for a few minutes. From your perspective, for those minutes, the android was endowed with consciousness. Thus there need be no truth or falsity to the statement “My friend standing before me is conscious.” Your brain decides that the android–best friend standing in front of you is conscious, and that is what you perceive to be true.
According to Graziano's “attention schema” theory, our own consciousness is also a perceptual construct—a unique one that emerges when the brain applies the same perceptual attribution recursively to itself. We attribute consciousness to others as part of our perceptual model of what they are paying attention to (an inference particularly useful for predicting their behavior). This model describes the process of attention as a mysterious something extra in the brains of beings that are selectively processing information that guides their behavior. When the brain applies the model to itself, “I” become endowed with this extra something as well—although, as with the android, it was never there in the first place.
According to the theory, consciousness is to attention what the body schema is to the body: it is the brain's perceptual description of its own process of attention. The two phenomena are thus locked “in a positive feedback loop,” which explains the tight connection between attention and consciousness. In essence, consciousness is a descriptive story about a real physical phenomenon (attention). The ink in which the story is written (neural activity) is real, and the physical phenomenon that the story is “about” (attention) is real. But, like the talking puppet, the story itself need not be real. We say that we have consciousness, and that it seems irreducible to physical phenomena, because that is how the brain describes the process of attention (in ourselves and in others): as something ineffable.
I'll also give you a clip from my abstracting of the book:
The heart of the theory is that awareness is a schematized, descriptive model of attention. The model is not perfectly accurate, but it is good enough to be useful. It is a rich information set, as rich as a sensory representation. It can be bound to a representation of an object as though it were another sensory attribute like color or motion….the purpose of a model in the brain is to be useful in interacting with the world, not to be accurate.

The body schema and the attention schema may share more than a formal similarity. They may partially overlap. The body schema is an internal model— an organized set of information that represents the shape, structure, and movement of the body, that distinguishes between objects belonging to the body and objects that are foreign.
In the present theory, the attention schema is similar to the body schema. Rather than representing one’s physical body, it models a different aspect of oneself, also a complex dynamical system, the process of attention— the process by which some signals in the brain become enhanced at the expense of others. It is a predictive model of attention, its dynamics, its essential meaning, its potential impact on behavior, what it can and can’t do, what affects it, and how. It is a simulation. The quirky way that attention shifts from place to place, from item to item, its fluctuating intensity, its spatial and temporal dynamics— all of these aspects are incorporated into the model.

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