Consciousness and the Social Brain

reality of Item I. We might be outraged by the identification, just as Newton’s contemporaries were outraged when told that the physical reality of white light is a mixture of all colors. There is no reason to suppose that we would recognize Item I as awareness.
    The thing to which the brain has cognitive access, and therefore the thing we describe when we report on awareness, is not Item I but rather the brain’s informational depiction of it, Item II. The properties that we attribute to awareness are properties depicted in Item II.
The Real Item on Which the Representation Is Based

    One does not need to look far for the Item I, the real item on which the report of awareness is based. Like seeing a rock and then investigating and finding out that what you see is not merely an illusion,that there is indeed a physical object in front of you, so too we can find that awareness is not merely an illusion with no basis but that it has a real, physical item on which the information is based.
    Consider again the case of white light. Most of the time that people report the experience of white it is because a broadband mixture of wavelengths is available to the eyes. The match, incidence by incidence, is close. It is not exact because a perceptual model is not perfectly accurate. Sometimes people report seeing white in the absence of the expected physical stimulus. Sometimes the broadband stimulus is present and people report a different color. Visual illusions abound. But by and large, almost all the time, that physical stimulus causes perceptual white. The two are correlated.
    Following the same logic, we should look for a physical, objectively measurable item that is almost always present when people report the presence of awareness. There is such an item, a physiological process in the brain, the process of attention. Almost uniformly, when you attend to an item, you report being aware of it. 11 – 14 The match, however, is not perfect. There are instances when it is possible to attend to something by all objective measures, meaning that your brain can selectively process it and react to it, and yet at the same time you report that you have no awareness of it. 11 , 12 , 15 – 17 These effects can occur in some cases of brain damage but can also be induced in normal healthy volunteers. Awareness and attention are therefore not the same, given that they can be separated. But they are typically associated. When the physical, measurable process of attention engages in the brain, when attention is directed at thing
X
, people almost always report the presence of awareness of thing
X
. For this reason, I argue that attention is Item I, the real physical item, a physical process, and awareness is Item II, the informational representation of it.
    Attention, physiological attention as it is understood by neuroscientists, is a procedure. It is a competition between signals in the brain. It occurs because of the specific way that neurons interact with each other. One set of signals, carried by one set of neurons, rises in strength and suppresses other, competing signals carried by otherneurons. For example, the visual system builds informational models of the objects in a scene. If you are looking at a cluttered scene, which informational model in your brain will win the competition of the moment, rise in signal strength, suppress other models, and dominate the brain’s computations? This competition among signals—the process by which one signal wins and dominates for a moment, then sinks down as another signal dominates—is attention. Attention may be complicated, but it is not mysterious. It is physically understandable. It could be built into a circuit.
    The correspondence between awareness and attention is close. In the previous chapter I outlined a list of similarities, and in later chapters I will discuss the relationship in greater detail. The two are so similar that it is tempting to think they might be the same thing with no distinction at all. But there is a fundamental difference. Attention, the competition among signals and the enhancement of signals in the brain, is a mechanistic process. It is not explicit knowledge. Awareness, in contrast, is accessible as explicit knowledge. The brain
does
attention but
knows
awareness.
    The relationship between attention and awareness is therefore exactly the relationship between Item I and Item II, between a real thing and a representation of it in the brain that is