As we go through life, our brains run different processing modes. Some – the attention and sensory systems – result in very similar experiences of the world: what colour the sky is, how warm the day feels.

But there is another, deeper side to the brain which weaves together your memories, goals, beliefs and emotions into a continuous sense of self. This allows you to experience the world not as it is, but as it matters to you personally.

This unique inner world is supported by the brain’s default mode network (DMN). This links together several areas including in the prefrontal cortex (at the very front of the brain) and the parietal lobe (at the back).

These areas of the DMN are, in evolutionary terms, relatively recent. As human brains expanded dramatically between around 800,000 and 200,000 years ago, those regions grew in size and complexity compared with our closest primate relatives. They are more likely to express genes that are uniquely human, related to brain development and function.

Our latest research explores to what extent the DMN explains what makes each of us unique. Put another way, we are attempting to understand what makes you “you”.

While ancient deep regions of the brain, shared with all vertebrates, support basic........

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