The biggest flaw in human decision-making – and how to fix it

Behavioural scientists Daniel Kahneman and Olivier Sibony explain why “noise” in professional judgements harms everything from criminal justice to medical treatments

By Graham Lawton

If you have ever jumped to the wrong conclusion, made a terrible mistake thanks to your inbuilt biases or been subtly nudged back to your senses, then you are (a) human and (b) already on personal terms with the work of Daniel Kahneman, Olivier Sibony and Cass Sunstein. Thanks to their academic and popular writing, the world is now very familiar with what are collectively called “cognitive biases” – systematic errors in human thinking – and ways to correct them.

Sunstein co-wrote the highly influential book Nudge: Improving decisions about health, wealth and happiness with Richard Thaler, while Kahneman popularised the work that won him the Nobel prize in economics in 2002 with his book Thinking, Fast and Slow. Sibony is the author of You’re About to Make a Terrible Mistake: How biases distort decision-making and what you can do to fight them.

You may think that, in no small part thanks to their efforts, the swamp of human fallibility has been well and truly drained by now. But that would be yet another mistake. Kahneman, Sibony and Sunstein say there is an even more important source of warped decision-making. The three have banded together in a behavioural science supergroup to draw attention to what they call “noise” – persistent inconsistencies in professional judgements that lead to bad outcomes in all walks of life.

Kahneman and Sibony spoke to New Scientist about the group’s new book Noise: A flaw in human judgment (Little, Brown Spark in the UK; William Collins in the US). Sunstein was due to join the conversation, but was called away at the last minute by his …