Consciousness and the Social Brain

Mirror-Neuron Story

    The mirror-neuron story is still controversial. The experimental support is far from complete. Perhaps the greatest weakness in the mirror-neuron story right now is that the experimental support is still circumstantial. The results are mainly correlative. Mirror neurons may be active when you watch someone else’s behavior; but do mirror neurons actually
cause
you to understand someone else’s behavior?
    Alternative views of mirror neurons have been offered. For example, perhaps the purpose of mirror neurons is not to understand the actions of others but to facilitate imitation. We learn by imitation; perhaps we are wired to translate sight into action. After all, monkeys are good at imitation but rather poor at social cognition compared to humans, and monkeys have plenty of mirror neurons.
    Another alternative interpretation of mirror neurons, recently suggested, is that they are a byproduct without any specific function, merely a symptom of the frequent association between the sight of the hand and the control of the hand. 9 , 10 Every time you grasp something you also see yourself do it, and by association, by repetition, neurons in areas scattered throughout the brain may become entrained to respond to both conditions. In this view, mirror neurons are not part of any machinery for social perception. Instead, they are a meaningless symptom of other more important functions.
    This debate about mirror neurons can only be resolved by further experiments and especially by more direct experiments. Tosupport the mirror-neuron story, an experiment will need to be done in which the mirror neurons are temporarily disrupted. As a result, the person or monkey should have a specific, temporary drop in ability to understand the actions of others. Another experimental approach might be to electrically excite a small clump of mirror neurons in person A, say a clump of mirror neurons that encodes a precision grip, and then determine if person A is more likely to think that person B has made a precision grip. The mirror-neuron story needs a direct link showing that mirror neurons
cause
social perception. With that direct link established, it would then be possible to move forward and work out exactly how mirror neurons contribute to social perception. To be fair, however, the complaint that “it needs more data” could be leveled against almost any theory out there.
    The mirror-neuron story has had an immense impact on neuroscience, psychology, and philosophy. Simulation theory provides deep insight into how people go about understanding people, how people empathize with each other, and how under some circumstances people may
fail
to empathize with each other. The theoretical implications are huge. Yet simulation theory suffers from two main gaps in its logic that are commonly noted. I will briefly describe them in the following sections. To be clear, I am not arguing against the mirror-neuron story. I find it extremely interesting and of great potential importance. It deservedly remains an area of active research. In the following sections I focus on certain logical gaps in the theory because I believe the gaps can be closed. The difficulties can be resolved by combining simulation theory with the expert system approach to social cognition. The two methods, working together, get around the obstacles.
Difficulty 1: No Clear Labeling of Individuals

    In simulation theory, you understand someone else’s thoughts, emotions, and actions by activating the same machinery in your own brain. But the theory does not provide any obvious way to distinguishyour own thoughts, intentions, and emotions from someone else’s. Both are run on the same hardware. If the simulation theory is strictly true, then how can I tell the difference between my own inner experiences and someone else’s that I am simulating? For that matter, if I am in a room with five other people, if I am engaged in social perception and social cognition, building an understanding of their minds and motives, then how can I tell which mental states belong to which people? If motivations and thoughts, intentions and actions are all simulated on the same hardware in my brain, then how can I sort what belongs to whom?
Difficulty 2: Circularity

    Simulation theory, at least in its simplest form, is circular. The essential idea is that to know someone else’s state of mind, you re-create that state of mind in yourself. But how can you re-create a state