Do you ever have trouble remembering whatshisface? Or struggle to recall which guy with a beard is Joel from accounting?
So it seems, humans have a limit to the number individual human faces they can recognize. Now, for the first time, scientists have managed to pin down the number of faces the average human knows, and it's actually quite a lot – somewhere between 1,000 and 10,000 faces, with an average of around 5,000.
For almost 200,000 years, humans lived in small close-knit groups made up of 100 individuals or less. Then came agriculture, around 10,000 BCE, where a surplus of food meant we could start to build villages and towns, then eventually cities and megacities. Despite this being a relatively new development in the history of humans, it seems that our brains are hardwired to deal with a surprisingly high number of faces.
“The ability to distinguish different individuals is clearly important – it allows you to keep track of people’s behavior over time, and to modify your own behavior accordingly,” explained Dr Rob Jenkins, from the Department of Psychology at the University of York, in a statement.
The new research, published this week in Proceedings of the Royal Society B: Biological Sciences was led by psychologists who were interested not in how many faces humans can know, but how many faces people actually know. The team reached their conclusion by asking volunteers to spend an hour writing down as many faces from their personal lives as possible, from their family to people they went to school with, then asked them to do the same for famous public figures, from politicians to sportspeople. They were next shown thousands of photographs of famous people and asked which ones they recognized.
Together, these experiments showed that people recognized between 1,000 and 10,000, with the average being 5,000 faces. However, the researchers suspect that the upper limit could be even higher among some people.
It remains a little unclear what dictates the strength of a person’s so-called “facial vocabulary”. Like most tasks and abilities, some people simply seem to just be good at it. Although the research did not explicitly look into this, the researchers believe it could be explained by an individual’s lifestyles, with urban-dwelling people being better trained at recognizing faces due to their human-filled environment.
“The range could be explained by some people having a natural aptitude for remembering faces. There are differences in how much attention people pay to faces, and how efficiently they process the information," Dr Jenkins added.
“Alternatively, it could reflect different social environments – some participants may have grown up in more densely populated places with more social input.”