Psychologists' face off reveals humans can recognise 5,000 people
Psychologists' face off reveals humans can recognise 5,000
people
University of York says first evidence-based study nails
down facial-recognition ability
The scientists asked volunteers to spend an hour
recalling as many faces as they could from their private lives, covering old
school friends, work colleagues, past partners and colleagues.
By Ian Sample Science editor Wed 10 Oct 2018 04.55 EDT
The next time an old friend meets your greeting with a
quizzical who-are-you stare, you’re right to take offence: new research
suggests the average person can recognise 5,000 different faces.
Psychologists at the University of York embarked on the
study after realising that for all the work scientists have done on faces, they
had never nailed down, even roughly, the number of faces the average human
knows. They say it is the first evidence-based estimate of this figure.
Through a series of recall and recognition tests on
volunteers, the researchers discovered that the human ability to recognise
faces varies enormously. The study found that people know between 1,000 and
10,000 faces of friends, family members, colleagues and celebrities, with most
racking up about 5,000.
“We were quite surprised by how high the top end was,”
said Mike Burton, a professor of psychology who led the research at the
University of York. About 2% of the population are thought to experience “face
blindness” or prosopagnosia.
“We’ve studied faces for years and years and the main
thing we always find is that there’s a huge difference between our ability to
recognise familiar versus unfamiliar faces. People are surprisingly bad at
checking a real face against a photo ID, and yet we recognise friends and colleagues
over a huge range of conditions,” said Burton.
“The brain is doing something different with familiar and
unfamiliar faces and that has been at the heart of our science for a long time.
But we realised we were missing something if we didn’t know how many familiar
faces people do recognise.”
Given the social
lives of our ancestors, the ability to recognise thousands of individuals might
seem like overkill
Rob Jenkins,
University of York
The scientists asked volunteers to spend an hour
recalling as many faces as they could from their private lives, covering old
school friends, work colleagues, past partners and colleagues. They then moved
on to famous faces: actors, musicians, sports stars, politicians and so on. By
recording how the volunteers’ recall rates slowed down, the psychologists
estimated when they would run out of faces.
In the next part of the study, the volunteers were shown
thousands of photographs of famous people and tested on how many they
recognised, even if they could not name the person. The scientists only counted
an individual as recognised if the volunteer knew them from two different
pictures.
The researchers arrived at the 5,000 figure by combining
the results from both parts of the study. While the number may seem high, given
that humans evolved in small groups, it may simply reflect the social
importance of recognising friends and foes and vast number of faces we are now
exposed to. Details of the work are published in Proceedings of the Royal
Society B.
We underestimate
the threat of facial recognition technology at our peril
Cynthia Wong
“Given the social lives of our ancestors, the ability to
recognise thousands of individuals might seem like overkill,” said Rob Jenkins,
a psychologist at University of York and co-author on the study. “But there are
plenty of examples of overkill in nature. The venom of some spiders can kill a
horse, even though the spider presumably has no ambitions to eat the horse.”
Equipped with such impressive facial recognition skills, it may be that we have
little choice but to remember so many.
Burton said the research could ultimately improve
automatic face recognition technology. Today’s best systems are good at
spotting “strangers” but cannot outperform a human when it comes to recognising
people the person is familiar with. “If we want to make the next step, we’ll
need to start copying that,” said Burton.
Comments
Post a Comment