What if you could never forget a face? A group of people newly discovered to science have been dubbed 'Super Recognisers'.
They have an extraordinary ability to recognise faces of everyone they meet, now matter how fleeting the encounter or how long ago.
At the other extreme, imagine looking in the mirror and not recognising who was staring back at you.
Or not knowing which is your own child at the school gates.
People with prosopagnosia or face blindness have those kinds of experiences every day.
Claudia Hammond explores the science of face recognition.
She uncovers the extremes of a skill that is fundamental to social interaction and yet science is only just beginning to understand.
She talks to neuroscientists have done some of the first FMRi brain scans to find out more about how our brains register faces.
As many as 1 in 50 people are prosopagnosic but many won't know they have a problem.
What are the implications for border control, policing and eye witness evidence? Also everyone struggles to recognise faces of people they don't know but what are the consequences for criminal justice?
Claudia Hammond investigates the science of face recognition.