CONSCIOUSNESS AND OTHER MINDS

Chris Frith
Wellcome Department of Cognitive Neurology
Institute of Neurology
University College London

Much of our conscious experience is concerned with thinking about possible courses actions and then carrying them out. When we think about our actions increases of neural activity can be detected in the anterior cingulate cortex at the front of the brain. But we can also carrying out quite complex actions with any consciousness of what we are doing or of the stimuli that are guiding our actions. If we measure the time at which we become conscious of selecting an action, we find that this does not occurs until 100s of milliseconds after the brain activity has started. Clearly we do not need consciousness for selecting and controlling our actions. So why is awareness of our actions such a strong feature of consciousness?

While we are not aware of selecting an action until after the associated bran activity has started, we are aware of initiating an action before the movement actually begins. This has the effect that, in our consciousness, cause (selecting an action) and effect (initiating that action) are tied more closely together. This gives us a stronger sense of agency; the feeling that we are in control of our own actions. This sense of our own agency enables us to adopt an 'intentional stance' when we try to understand the actions of other people. We predict what someone will do next on the basis of her intentions, desires and beliefs. Brain imaging studies show that when we try to predict the behaviour of others activity is observed in medial prefrontal cortex adjacent to the areas that is activated when we attend to our own actions. I suggest that there is a common system for consciously representing the causes of our actions and the causes of the actions in others. This system enables us to share our experiences.