Consciousness and the Social Brain

discuss the integrated information approach, in each case explaining how the attention schema theory builds on the previous work.
The Self-Narrative

    We humans construct a narrative to explain other people’s behavior. We constantly engage in social story-telling. So-and-so must be doing this or saying that because of a particular mood or agenda, a belief or reason. Do we use the same indirect process to construct a narrative of our own behavior? Perhaps we construct a self-narrative, a stream-of-consciousness account of ourselves, of our motives and reasons. Can a social narrative, turned inward, account for consciousness? This section describes some of the main social hypotheses about consciousness. Subsequent sections describe the most commonly noted difficulties with these theories.
    In 1970, Gazzaniga 2 formulated one of the earliest examples of this approach to consciousness. He proposed that the human brain contains an “interpreter,” a mechanism in the left hemisphere that constructs a verbal narrative to explain behavior.
    Gazzaniga’s proposal was based on experiments using split-brained patients. In order to control the spread of epilepsy, these patients underwent a surgical cut to the corpus callosum, the bundle of nerve fibers that connects one hemisphere to the other. After the surgery the two hemispheres were unable to communicate with each other directly. The left hemisphere was functionally isolated from the right. In these patients, therefore, it was possible to test the abilities of the two hemispheres separately. Since speech is generally controlled by the left hemisphere, anything the patient said was an indication of left-hemisphere thought. Yet the right hemisphere had enough linguistic skill to understand basic instructions and to act on them.
    Gazzaniga’s key experiment was to give instructions specifically to the right hemisphere of a patient, allow the subject to act out those instructions, and then ask the left hemisphere to explain why the patient had chosen to act in that way. For example, the right hemisphere might be instructed, “Point to your foot.” The subject does so. How does the left hemisphere explain the behavior? The left, verbal hemisphere explains in words why that particular action was performed. But lacking any knowledge of the real reason, it makes up its own reason and seems confident in that confabulation. These split-brained subjects spun false, after-the-fact explanations of their own behavior with extraordinary confidence.
    From this result Gazzaniga suggested that consciousness was essentially a tale that the brain tells itself to explain what it is doing and why it is doing it. He proposed that the left hemisphere contains something he called the interpreter, which spins explanatory stories about oneself as well as stories about other people.
    This idea that consciousness is after-the-fact, that we make up a story to explain ourselves to ourselves, has cropped up many timesin the literature in many variants. A similar proposal was made in 1977 by Nisbett and Wilson. 3 We tend to think of consciousness as a direct access to our own decisions, ideas, and thoughts. Yet Nisbett and Wilson suggested that, contrary to popular belief, the human brain has no privileged access to its own internal processes. We know about our mental states using the same tricks and inferences that we use to reconstruct the mental states of other people. We tell ourselves a story about ourselves. As a consequence, we routinely and confidently make up incorrect reasons for our own behavior.
    Yet another variant of the same idea was proposed by Libet and colleagues. 4 These researchers focused on conscious choice—our sense of intentionality. We consciously choose to pick up a coffee cup, turn on a light, stand up, open a door, and so on. We all feel as though some inner consciousness first decided on how to act, and then having made the decision, directed our bodies to carry out the act. Conscious decision comes first, action comes second. Yet Libet and colleagues performed an experiment that suggested the order may be reversed. In that experiment, the action to be performed was simple. People were asked to press a button. They could press the button any time they wanted to. The choice was theirs. They watched the second hand on a clock and noted the precise time at which the thought, the intention to act, entered their minds. At the same time, the person had a set of electrodes