Humans can recognise an astounding 5000 faces

Ever wondered where you may have seen someone before? A lecture, waiting for a train at Euston, or maybe a dream? Researchers from the Psychology department at the University of York have concluded that the average person can recognise up to 5,000 faces.

It’s one of those intriguing questions that you never pay any mind to (another being how far the human eye can see, three miles at sea level for those interested). With the explosion of social media in the past few years we are exposed to a growing quantity of faces, a stark contrast to people who lived 100 years ago. With the increase in population density over the previous centuries, a higher capacity for facial recognition is a substantial advantage from an evolutionary standpoint.

With the explosion of social media in the past few years we are exposed to a growing quantity of faces, a stark contrast to people who lived 100 years ago

It has been stipulated that the fusiform gyrus (part of the temporal and occipital lobes of the brain) is responsible for the capability to recall facial features. Having known about this for a while, it is surprising that only now has a group gathered quantitative evidence to see how many faces the average person can remember.

Psychologists at York ran two separate hour-long tests, one based upon recall and the other recognition. Volunteers were first asked to recall family members, friends from their past and present, as well as famous figures and celebrities. The second test involved the researchers showing images of famous individuals, and the participant only had to recognise the face.

It has been stipulated that the fusiform gyrus (part of the temporal and occipital lobes of the brain) is responsible for the capability to recall facial features

Combining the data obtained from both tests, an estimate was made as to how many the participant would be able to recognise in total. The conclusion was that there is huge variety on how many faces a human being can recognise; between 1,000 and 10,000 dependent on the volunteer. Co-author of the research paper and York psychologist Rob Jenkins considers this an exorbitant range, stating that “given the lives of our ancestors, the ability to recognise thousands of faces may seem like overkill.”

As a result, it was calculated that the average number of faces a human being can recognise is approximately 5,000, indicating that evolution was taking no chances in distinguishing a friend from an enemy. This is in spite of the fact that humans co-existed in significantly smaller groups during the earlier stages of life on earth.

The average number of faces a human being can recognise is approximately 5,000, indicating that evolution was taking no chances in distinguishing a friend from an enemy

In the past year several ranges of new phones have included novel facial recognition technology (your usual names, Samsung and Apple), but these systems pale in comparison to the human capability. Further understanding of how we recognise features in such detail could be key to developing more sophisticated systems, which could also help in the fight against fraud and cyber security, which is as big a threat as ever.