The most fundamental human trait? That we can change.

It has been said there are two kinds of people in the world: those who believe there are two kinds of people in the world, and those who don't.

I'm with the latter group. However, binaries still have their place, if only for explanatory purposes, and much of the criticism waged against them relates to people failing to grasp that binaries need not be exhaustive nor even mutually exclusive.

Tonight I am chairing an RSA event  with the esteemed Professor Carol Dweck in the RSA Great Room, and as part of my preparation it has become clearer to me just how much of her work is based on an important binary.

At the risk of trying to distill an enormous body of work down to its essence, Professor Dweck's research shows that people typically show inclinations towards one of two main 'mindsets' (implicit theories) about human traits. The first is known as a fixed mindset i.e. traits like intelligence, goodness and so forth cannot really be changed. The second is a growth mindset i.e. such traits are not fixed, and people can take steps to change them over time.

From this core binary, Professor Dweck has built up a really impressive body of research that not only touches on how we should praise outcomes ('that was good, you are really smart' tends to promote a fixed mindset; 'that was good, you really put a lot of effort into that' tends to promote a growth mindset) but also speaks to why political conflicts are so intractable. If you believe people in the other country/political party/camp are always going to be the way they are, your motivation to work together is diminished.

Dweck's perspective is a classic success story of a complex idea with practical applications that can be simply expressed. However, what I find inspiring about it is more philosophical.

As Director of the Social Brain Centre, I have noticed that whenever you talk about 'the brain' or 'human nature' most people tacitly assume that you are talking about something relatively fixed. In fact, the whole point of our interest in this perspective is that the evidence points the other way.

It is easy to get dazzled by experiments in social psychology and behavioural economics that show up bizarrely irrational human behaviour, and Daniel Kahneman, for instance, suggests ( though not to universal assent) that there is not much we can do to change such cognitive quirks and biases. It is also easy to hear words like 'genes', 'evolution' and 'neuroscience' and think that we are talking about immutable laws of nature.

Dweck's work is a beacon of light precisely because it pushes us in the opposite direction. We may have certain natural constraints that shape our preferences and our probabilities, but Dweck's point is that we are built not so much to be one way or the other in perpetuity, but to become different and better:

"Debates about human nature often resolve around what is built in. Are people born to be aggressive? Is antipathy towards the outgroups a part of human nature? Is Willpower severely limited by biology?

To me, however, the hallmark of human nature is how much of who we are-and who we become-is not built in. The hallmark of human nature is each person's great capacity to adapt, to change, and to grow. In fact, perhaps what is built in is this capacity to learn and change according to the world you find yourself in."

(Carol Dweck in American Psychologist, November 2012)

The emphasis on a growth mindset is therefore no mere educational tool, in an overloaded toolbox (although it's a rather good one). The point is deeper. Developing a growth mindset is a fundamental existential, philosophical and even political outlook. Dweck's work is therefore full of hope, because it's grounded in informed optimism about our capacity to change ourselves and our world for the better.

By Jonathan Rowson: @Jonathan_Rowson