Children’s face recognition software is the same as adults’ by the time they are five years old, according to research at the Australian National University. But a question mark hangs over the extent to which face recognition – an ability critical to survival in primate social groups – is hard wired.

Crookes, a PhD candidate in the Department of Psychology, has been assessing face recognition skills in babies aged three and a half months to four and a half months old and in children aged five to ten years old to track the development of the ability that enables us to distinguish friend from foe. The subjects, drawn from friends and the Canberra community, are shown images of faces on a computer screen, with their response recorded on a video camera. Crookes assesses face recognition ability from the difference in the time babies and infants spend staring at familiar and unfamiliar faces.

“We show them the same image over and over again until they get bored with it and look away,” she says. “Then we show them a new one to see if they look at it longer after realising it’s not the same one.” The difference is usually a matter of seconds. By the time they are five years old, children are processing the visual information in the same way as adults, she says. “We know that adults take information from across the entire face – measuring distances between features. Five-year-olds do it in the same way.”

To find out whether the ability is genetically coded or learnt, Crookes is testing babies. “We know that babies are better than adults at some things,” she says. She says new born babies can recognise human faces. They can even recognise monkey faces, whereas all monkeys look the same to adults. However, they lose the ability to recognise monkey faces by the time they are nine months old unless it is reinforced. “If you keep showing them monkey faces they can continue to do it at nine months,” she says, adding that she is due to start testing babies’ ability to recognise horse profiles.

Magnetic resonance imaging research suggests that face recognition is performed by part of the temporal lobe called the fusiform face area. The ability is impaired in prosopagnosia, or “face blindness”, a rare disorder that affects people’s ability to recognise even their own family. Sufferers rely on cues like hair colour, height, gait and voice to tell people apart. Face recognition is also thought to be impaired in some cases of autism.

The ANU research could point to ways to teach people with impaired face recognition ability to compensate. Crookes transferred to ANU to do her Honours year after winning an ANU Honours Scholarship, and stayed on to do a PhD. “I love it,” she says. “The kids are great! Working with five- and six-year-olds is so cute.”