At New York University, Sir Henry Wellcome Postdoctoral Fellow Dr. Steve Fleming is exploring the neural basis of metacognition: how we think about thinking, and how we assess the accuracy of our decisions, judgements and other aspects of our mental performance.
Metacognition is an important-sounding word for a very everyday process. We 'metacognize' whenever we reflect upon our thinking process and knowledge.
It's something we do on a moment-to-moment basis, according to Dr. Steve Fleming at New York University. "We reflect on our thoughts, feelings, judgements and decisions, assessing their accuracy and validity all day long," he says.
This kind of introspection is crucial for making good decisions. Do I really want that bar of chocolate? Do I want to go out tonight? Will I enjoy myself? Am I aiming at the right target? Is my aim accurate? Will I hit it? How sure am I that I'm right? Is that really the correct answer?
If we don't ask ourselves these questions as a kind of faint, ongoing, almost intuitive commentary in the back of our minds, we're not going to progress very smoothly through life.
As it turns out, although we all do it, we're not all equally good at it. An example Steve likes to use is the gameshow 'Who Wants to be a Millionaire?' When asked the killer question, 'Is that your final answer?', contestants with good metacognitive skills will assess how confident they are in their knowledge.
If sure (I know that I know), they'll answer 'yes'. If unsure (I don't know for sure that I know), they'll phone a friend or ask the audience. Contestants who are less metacognitively gifted may have too much confidence in their knowledge and give the wrong answer - or have too little confidence and waste their lifelines.
Metacognition is also fundamental to our sense of self: to knowing who we are. Perhaps we only really know anyone when we understand how, as well as what, they think - and the same applies to knowing ourselves. How reliable are our thought processes? Are they an accurate reflection of reality? How accurate is our knowledge of a particular subject?
Last year, Steve won a prestigious Sir Henry Wellcome Postdoctoral Fellowship to explore the neural basis of metacognitive behavior: what happens in the brain when we think about our thoughts and decisions or assess how well we know something?
One of the challenges for neuroscientists interested in metacognition has been the fact that - unlike in learning or decision making, where we can measure how much a person improves at a task or how accurate their decision is - there are no outward indicators of introspective thought, so it's hard to quantify.
As part of his PhD at University College London, Steve joined a research team led by Wellcome Trust Senior Fellow Professor Geraint Rees and helped devise an experiment that could provide an objective measure of both a person's performance on a task and how accurately they judged their own performance.
Thirty-two volunteers were asked to look at a series of two very similar black and grey pictures on a screen and say which one contained a brighter patch.
"We adjusted the brightness or contrast of the patches so that everyone was performing at a similar level," says Steve. "And we made it difficult to see which patch was brighter, so no one was entirely sure about whether their answer was correct; they were all in a similar zone of uncertainty."
They then asked the 'killer' metacognitive question: How sure are you of your answer, on a scale from one to six?
Comparing people's answers to their actual performance revealed that although all the volunteers performed equally well on the primary task of identifying the brighter patches, there was a lot of variation between individuals in terms of how accurately they assessed their own performance - or how well they knew their own minds.
Magnetic resonance imaging (MRI) scans of the volunteers' brains further revealed that those who most accurately assessed their own performance had more grey matter (the tissue containing the cell bodies of our neurons) in a part of the brain located at the very front, called the anterior prefrontal cortex. In addition, a white-matter tract (a pathway enabling brain regions to communicate) connected to the prefrontal cortex showed greater integrity in individuals with better metacognitive accuracy.
The findings, published in Science in September 2010, linked the complex high-level process of metacognition to a small part of the brain. The study was the first to show that physical brain differences between people are linked to their level of self-awareness or metacognition.
Intriguingly, the anterior prefrontal cortex is also one of the few parts of the brain with anatomical properties that are unique to humans and fundamentally different from our closest relatives, the great apes. It seems introspection might be unique to humans.
"At this stage, we don't know whether this area develops as we get better at reflecting on our thoughts, or whether people are better at introspection if their prefrontal cortex is more developed in the first place," says Steve.
More information: Wellcome Trust