The eyes have it

Psychologist Dr Craig Thorley said accurately estimating age can be important for legal or public safety reasons.

“Accurately estimating age can be important for situations such as police investigations, where witnesses are asked to describe an offender and estimate their age,” he said.

“It’s also relevant for bartenders trying to estimate a customer’s age to determine if they’re legally able to purchase alcohol.”

Dr Thorley said there are a number of cues people use to estimate a stranger’s age, whether consciously or unconsciously.

“Facial features change in significant but predictable ways with age,” he said.

“This includes changes such as wrinkles, thinner and saggier skin, eyes appearing smaller, noses and ears becoming elongated, and hair becoming greyer and thinner.”

Dr Thorley asked participants to estimate the age of a stranger in a photograph, both with and without “disguises”, to establish what most affected the accuracy of their guesses.

“I found that a person’s ability to accurately estimate a stranger’s age decreased when the stranger worse sunglasses, but not when they were wearing a hat,” he said. “My results suggest that the cues we receive from eyes are stronger than the cues we receive from hair.”

Dr Thorley also found that our accuracy depends on how similar we are in age to the stranger, and if we’re from the same ethnic group.

“The closer we are in age to the stranger, the more likely we are to accurately guess their age,” he said.

“I also found that participants are less accurate at estimating age when the stranger is of a different ethnic group.”

Dr Thorley’s findings have implications for circumstances where estimating a stranger’s age is necessary, such as when witnessing a crime or selling alcohol.

“By knowing the margin of error, we can better equip police and licensed bars to adapt their processes, such as expanding a police investigation to include a larger age bracket, or by asking anyone who looks under 25 for ID.”