Consciousness and the Social Brain

ways of the scientific blind alleys in understanding biological evolution. 9 Charles Darwin published his book
The Origin of Species
in 1859, 10 but long before Darwin, naturalists had already suspected that one species of animal could evolve into another and that different species might be related in a family tree. The idea of a family tree was articulated a century before Darwin, by Linnaeus, in 1758. 11 What was missing, however, was the trick. How was it done? How did various species change over time to become different from each other and to become sophisticated at doing what they needed to do? Scholars explored a few conceptual blind alleys, but a plausible explanation could not be found. Since nobody could think of a mechanistic explanation, since a mechanistic explanation was outside the realm of human imagination, since the richness and complexity of life was obviously too magical for a mundane account, a deity had to be responsible. The magician made it happen. One should accept the grand mystery and not try too hard to explain it.
    Then Darwin discovered the trick. A living thing has many offspring; the offspring vary randomly among each other; and the natural environment, being a harsh place, allows only a select few of those offspring to procreate, passing on their winning attributes to future generations. Over geological expanses of time, increment by increment, species can undergo extreme changes. Evolution by natural selection. Once you see the trick behind the magic, the insight is so simple as to be either distressing or marvelous, depending on your mood. AsHuxley famously put it in a letter to Darwin, “How stupid of me not to have thought of that!” 12
    The neuroscience of consciousness is, one could say, pre-Darwinian. We are pretty sure the brain does it, but the trick is unknown. Will science find a workable theory of the phenomenon of consciousness?
    In this book I propose a theory of consciousness that I hope is unlike most previous theories. This one does not merely point to a magician. It does not merely point to a brain structure or to a brain process and claim without further explanation,
ergo consciousness
. Although I do point to specific brain areas, and although I do point to a specific category of information processed in a specific manner, I also attempt to explain the trick itself. What I am trying to articulate in this book is not just, “Here’s the magician that does it,” but also, “Here’s
how
the magician does it.”
    For more than twenty years I studied how vision and touch and hearing are combined in the brain and how that information might be used to coordinate the movement of the limbs. I summarized much of that work in a previous book,
The Intelligent Movement Machine
, in 2008. 13 These scientific issues may seem far from the topic of consciousness, but over the years I began to realize that basic insights about the brain, about sensory processing and movement control, provided a potential answer to the question of consciousness.
    The brain does two things that are of particular importance to the present theory. First, the brain uses a method that most neuroscientists call attention. Lacking the resources to processes everything at the same time, the brain focuses its processing on a very few items at any one time. Attention is a data-handling trick for deeply processing some information at the expense of most information. Second, the brain uses internal data to construct simplified, schematic models of objects and events in the world. Those models can be used to make predictions, try out simulations, and plan actions.
    What happens when the brain inevitably combines those two talents? In the theory outlined in this book, awareness is the brain’ssimplified, schematic model of the complicated, data-handling process of attention. Moreover, a brain can use the construct of awareness to model its own attentional state or to model someone else’s attentional state. For example, Harry might be focusing his attention on a coffee stain on his shirt. You look at him and understand that Harry is
aware
of the stain. In the theory, much of the same machinery, the same brain regions and computational processing that are used in a social context to attribute awareness to someone else, are also used on a continuous basis to construct your own awareness and attribute it to yourself. Social perception and awareness share a substrate. How that central, simple hypothesis can