Externally observable components of human actions carry only a tiny fraction of the information that matters. Human observers are vastly more interested in perceiving or inferring the mental states - the beliefs, desires and intentions - that lie behind the observable shell. If a person checks her watch, is she uncertain about the time, late for an appointment, or bored with the conversation? If a person shoots his friend on a hunting trip, did he intend revenge or just mistake his friend for a partridge? The mechanism people use to infer and reason about another person's states of mind is called a 'Theory of Mind' (ToM). One of the most striking discoveries of recent human cognitive neuroscience is that there is a group of brain regions in human cortex that selectively and specifically underlie this mechanism.
The lab studies these brain regions for Theory of Mind, as a case study in the deeper and broader question: how does the brain - an electrical and biological machine - construct abstract thoughts?
Theory of Mind is an especially exciting case study because:
(*) Thinking about other minds is the foundation for both personal relationships and societal institutions, and the human capacities to read and write fiction, to teach skills and pass knowledge down generations, and to make moral judgments, especially to forgive accidents. Deficits of social cognition, like Autism, can be more devastating to individuals and their families than the loss of a limb or a sense.
(*) Theory of Mind is a perfect example of the essentially inductive nature of human thought. We don't just build up catalogues of perceptions. We go way beyond the "data" of experience, to infer complex, abstract, invisible causal mechanisms at work in the world.
(*) The brain regions involved in Theory of Mind are incredibly robust. We can find the same regions, in 90% of individual subjects, after just 20 minutes of scan time. Similarly reliable patterns of activation are routinely observed for perceptual mechanisms, like primary sensory and motor cortices, but rarely for dimensions of cognition as abstract and complex as Theory of Mind. The 'Theory of Mind' regions thus offer a rare window through the brain to the mind.
Work uses as many methods as we can get our hands on: especially functional magnetic resonance imaging (fMRI) in adults and children, but also transcranial magnetic stimulation (TMS), neuropsychological patient studies, and eye-tracking and behavioural methods with adults and infants. And while we mostly study social cognition, a few projects in the lab focus on other key examples of a neurally-localised uniquely human cognitive capacities: executive function, and language.