Consciousness and the Social Brain

of mind if you don’t already know what it is? Before Brain A can mirror the state of Brain B, it needs to know what state to mirror. Brain A needs a mechanism that generates hypotheses about the state of Brain B.
A Hybrid System: Combining Mirror Neurons with the Expert System

    The two conceptual difficulties with simulation theory disappear in a hybrid system that combines both approaches, the simulation approach and the expert system approach to social perception.
    In the hybrid system proposed here, the brain contains an expert system. This system probably includes the standard brain areas that light up in most experiments on social cognition, such as the TPJ, STS, and medial prefrontal cortex (MPFC). This system uses a convergence of information—how other people look and act, how they sound, prior information about them, their words, their gestures.The expert system, combining this information, constructs models of other minds. These models include reconstructions of the beliefs of others, the thoughts of others, the emotions of others, the intentions to make this or that movement, the goals of behavior, the state of another person’s attention, and so on.
    These models of minds are in essence elaborate hypotheses. They can be used to drive mirror-neuron networks that span much of the brain and that simulate and thereby refine the hypotheses. In this speculation, models of minds are constructed or coordinated by a restricted network of areas specialized in social intelligence, the network that is so commonly recruited when people engage in social thinking. That network is in a constant dialogue with a mirror-neuron system that includes most of the rest of the brain.
    The hybrid model makes a specific set of predictions. If your pre-motor hand area is damaged, you should still be able to perceive the hand actions of others. But the details and nuances, the mechanics of hand action, should be harder to understand. If your visual machinery is damaged, you should still be able to understand the concept of someone else seeing something. But the details and nuances should escape you. If you have deficient emotional circuitry, you should be able to understand that someone else is experiencing emotion, but the richness and nuance of that social understanding should be compromised. Losing the simulation machinery should not remove basic social perception or cognition, the ability to generate basic hypotheses about what other people are experiencing, but should limit the detail and richness of the perceptual models.
    One of the nagging difficulties of the expert system view of social thinking is that the expert system would need to be an expert on rather a large range of topics. Is the other person aware of that coffee cup? The social machinery must be informed about coffee cups. Is she aware of the chill in the room? The social machinery must be informed about skin temperature. Is she aware of the abstract idea that I am trying to get across, or is she distracted by her own thoughts? What emotion is she feeling? What movement is sheplanning? Why does her voice sound too loud? Why did she move so quickly? Why did she choose one cut of clothes over another? Social perception requires an extraordinary multimodal linkage of information. All things sensory, emotional, cognitive, intellectual, cultural, or action oriented must be brought together and considered in order to build a useful predictive model of the other person’s mind. It is implausible to talk about a specific expert region of the brain that performs all of social perception.
    In the hybrid system proposed here, the expert system does not need to be omniscient. It does not need to duplicate, in miniature, the expertise of the entire brain. The mirror-neuron phenomenon provides the diversity and computing power. During social perception, to understand what another person is seeing, the brain recruits visual areas; to understand what another person is doing, the brain recruits motor areas; to understand what another person is feeling, the brain recruits emotional processors; but at the center of this vast brain-wide network lies a restricted set of areas, specialists in social cognition. These areas coordinate the perceptual model of a mind, generate the initial hypotheses, and drive the mirror-neuron simulations.
Difficulty 1: Solving the Labeling of Individuals

    When we human think about each other, we do not conceive of a mind as merely a collection of