There is nothing more embarrassing than being stopped in the street by someone who recognises you when you haven't got a clue who they are. It is thought that around 2% of the population may suffer from prosopagnosia, a condition characterized by great difficulty in recognising faces. Scientists had thought that people could either recognise faces or they couldn't but researchers at Harvard University have found a group of people called 'super-recognisers' who can recognise people they meet in passing many years later. They gave standardized face-recognition tests to a number of people and some scored far above average. Some of the super-recognisers were able to recognise people who shopped in the same store as them months ago and one recognised a waitress who had served her five years earlier.
You can find out more about this research at