Consciousness and the Social Brain

placed on the scalp to monitor the electrical activity in the motor cortex, specifically in a region of the brain that plans movements of the finger.
    The result of the experiment was counterintuitive. People confidently reported a particular time on the clock to be the instant, the key moment, when the conscious choice to act entered their heads. Yet the activity in the motor cortex consistently rose up a moment earlier. The order was backward. First motor cortex planned the action, then the conscious decision kicked in. By implication, the human brain chooses an action by means of unconscious processes. A different system in the brain then obtains information that theaction is about to occur and constructs a story about how and why the act was intended. Consciousness, and in particular the conscious intention to act, is after-the-fact and indirect, as if we were observing ourselves and inferring our reasons.
    This view of intentionality is controversial and may represent only a part of a more complex story. 5 In some instances the conscious intention comes first; in other instances it comes second. The story is not as simple as the original experiment suggested. Nonetheless, the experiment had an enormous impact on the way researchers thought about the problem. The experiment helped promote the view that consciousness is a narrative that the brain spins to make sense of what it is doing.
    We certainly invent narratives to explain other people. But do we use the same brain machinery to explain ourselves? One way to get at this question is by a more direct measurement of brain activity, for example, by using a magnetic resonance imaging (MRI) scanner. Numerous studies, especially over the past ten years, have asked if the same brain areas are active when we think about other people and when we think about ourselves. When people are placed in an MRI scanner and asked to think about someone else’s thoughts or emotions, a specific network of brain areas consistently lights up. Many of the same brain areas are also recruited when people are asked to monitor their own mental states. 6 – 10 These experiments lend support to the hypothesis of consciousness as a social construct, or at least to the hypothesis that some aspects of self-knowledge depend on the same machinery that is used to construct narratives about other people’s minds.
    The idea of the social construction of consciousness, that consciousness depends on high-level social cognition, or on people building up an understanding of how minds work, or on people thinking about thinking, has been elaborated and extended by many researchers. In some versions of the hypothesis, my consciousness is much larger than my understanding of myself. It is my understanding of the social context, the social universe in which I live and my own place in that larger context. In that way of thinking consciousness isa function of groups of people and is not really a private matter. It is not a function of a single brain but is an interactive medium, a kind of social web of information within which humans are embedded as we relate to each other. 11 – 13
    I have now described at least some of the main experiments and ideas about social theories of consciousness. They are quite diverse. They range from verbal stories of ourselves, such as Gazzaniga’s interpreter, to conscious decisions that come after the fact, such as in the experiments of Libet and colleagues. They include experiments on networks of brain areas involved in social cognition, and they include some mind-bending speculations about consciousness as a group function instead of a property of individuals. Yet they all share certain characteristics. The social theories of consciousness share the following three properties.
    First, the brain actively constructs an elaborate description or model or narrative about its own processing.
    Second, that self-descriptive information is often wrong. The system that computes it has limited capacity and relies on limited cues.
    Third, the machinery that computes the self-description is also used to compute explanations of other people. We understand ourselves and other people partly through the same means.
    All three of these hypotheses are almost certainly correct. Given the range of experimental findings, it is hard to imagine how they could be wrong. However, the three properties by themselves do not necessarily explain the phenomenon of human consciousness. They may account