‘Humans ID 5,000 faces’

Forest app

PARIS, Oct 10, (Agencies): From family and friends to strangers on the subway and public figures on 24-hour news cycles, humans recognize an astonishing 5,000 faces, scientists said Wednesday in the first study of its kind.

Through most of history humans lived in small groups of a hundred or so individuals, a pattern that has changed drastically in recent centuries.

A study by scientists at Britain’s University of York found that our facial recognition abilities allow us to process the thousands of faces we encounter in busy social environments, on our smartphones and our television screens every day.

“In everyday life, we are used to identifying friends, colleagues, and celebrities, and many other people by their faces,” Rob Jenkins, from York’s Department of Psychology, told AFP.

“But no one has established how many faces people actually know.”

For the study, published in the journal Proceedings of the Royal Society B, Jenkins and his team asked participants to write down as many faces they could remember from their personal lives.

Jenkins

Recognized

The volunteers were then asked to do the same with people they recognized but did not know personally.

They were also shown thousands of images of famous people – two photos of each to ensure consistency – and asked which ones they recognised.

The team found an enormous range of the number of faces each participant could recall, from roughly 1,000-10,000.

“We found that people know around 5,000 faces on average,” Jenkins said.

“It seems that whatever mental apparatus allows us to differentiate dozens of people also allows us to differentiate thousands of people.”

The team said it believes this figure – the first ever baseline of human “facial vocabulary”, could aid the development of facial recognition software increasingly used at airports and criminal investigations.

It may also help scientists better understand cases of mistaken identity.

“Psychological research in humans has revealed important differences between unfamiliar and familiar face recognition,” said Jenkins.

“Unfamiliar faces are often misidentified. Familiar faces are identified very reliably, but we don’t know exactly how.”

While the team said it was focused on how many faces humans actually know, they said it might be possible for some people to continue learning to recognize an unlimited number of faces, given enough practice.

They pointed out that the brain has an almost limitless capacity to memorize words and languages – the limits on these instead come from study time and motivation.

The range of faces recognized by participants went far beyond what may have been evolutionarily useful: for thousands of years humans would likely only have met a few dozen people throughout their lives.

Jenkins said it was not clear why we developed the ability to distinguish between thousands of faces in the crowd.

A web-based application that monitors the impact of successful forest-rights claims can help rural communities manage resources better and improve their livelihoods, according to analysts.

The app was developed by the Indian School of Business (ISB) to track community rights in India, where the 2006 Forest Rights Act aimed to improve the lives of rural people by recognizing their entitlement to inhabit and live off forests.

With a smartphone or tablet, the app can be used to track the status of a community rights claim.

After the claim is approved, community members can use it to collect data on tree cover, burned areas and other changes in the forest and analyze it, said Arvind Khare at Washington D.C.-based advocacy Rights and Resources Initiative (RRI).

“Even in areas that have made great progress in awarding rights, it is very hard to track the socio-ecological impact of the rights on the community,” said Khare, a senior director at RRI, which is testing the app in India.

“Recording the data and analyzing it can tell you which resources need better management, so that these are not used haphazardly, but in a manner that benefits them most,” he told the Thomson Reuters Foundation.