WASHINGTON - Some people assert that they can never forget a face, even many years later, a claim which has now been substantiated by psychologists.

The new study suggests that skill in facial recognition might vary widely among humans. Previous research identified two percent of population as having ‘face-blindness’ or prosopagnosia, a condition characterised by great difficulty in recognising faces.

Now this new research by Harvard University shows that others excel in face recognition, indicating that the trait could be on a spectrum, with prosopagnosics on the low end and super-recognisers at the high end.

The research was led by Richard Russell, postdoctoral researcher in psychology at Harvard, with co-authors Ken Nakayama, Edgar Pierce, professor of Psychology, Harvard and Brad Duchaine, University College London.

The research involved administering standardised face recognition tests. The super-recognisers scored far above average on these tests-higher than any of the normal control subjects.

‘There has been a default assumption that there is either normal face recognition, or there is disordered face recognition,’ said Russell.

Super-recognisers report that they recognise other people far more readily than they are recognised.

For this reason, said Russell, they often compensate by pretending not to recognise someone they met in passing, so as to avoid appearing to attribute undue importance to a fleeting encounter.

One woman in the study said she had identified another woman on the street who served her as a waitress five years earlier in a different city, said a Harvard release.

Critically, she was able to confirm that the other woman had in fact been a waitress in the different city. Often, super-recognisers are able to recognise another person despite significant changes in appearance, such as aging or a different hair colour.

These findings were published in Psychonomic Bulletin & Review.