Daniel Kahneman

Widely regarded as the world's most influential living psychologist, Daniel Kahneman, reflects on his lifetime's research on why we make the "wrong" decisions.

He won the Nobel Prize for Economics for his pioneering work with Amos Tversky on the irrational ways we make decisions about risk. He directly challenged traditional economic orthodoxy that we are rational, logical and selfish in the choices we make, laying the foundations for behavioural economics.

And his research quantified how real people, rather than textbook examples, consistently make less than rational choices, prey to the quirks of human perception and intuition.

Claudia Hammond talks to him about "anchoring" and "priming" and why he fears for the behaviour of people motivated by money.

Conjoined Twins:
Could conjoined twin girls, joined at the head have two brains but share a mind? One girl is pricked for a blood test, her sister cries. Or one watches TV, the other laughs at the images her sister sees. What does the connection of these young girls' brains reveal about the difference between brain and mind?

Producers: Fiona Hill & Pam Rutherford.