The police can develop ‘tunnel vision’, where they overvalue evidence that supports their argument and discredit or ignore information that contradicts it. And it’s not just the police – this kind of process can happen to anyone, because incorrect information can seep into any of the coherent stories we construct to understand reality. To use a term stolen from one of the world’s leading legal psychologists, Peter van Koppen, we can all be ‘defective detectives’, struggling to be unbiased evidence collectors.
