A study determined that a person’s smiling image can be more easily matched to another shot of the same individual than a picture with a neutral expression.
Researchers at the University of York found that recognition rates increased by nine per cent when the subjects were smiling.
Dr Mila Mileva, at the university’s psychology department, said: “Photo ID is a significant part of our lives and yet we know that the human brain has a hard time matching photos of people to other photos
“Identity fraud is a real problem on many levels, so it is important that we do more research in this area to see how we can improve methods of identification.”
She added: “Our research suggests that replacing the neutral expression we usually use when taking identification photographs with an open mouth smile, can make face matching easier. As soon as there’s a mismatch in emotional expression, the matching accuracy drops substantially.
“We also had success in showing that an open mouth smile can help people to tell two similarly looking people apart.”
Researchers say future passports could be issued with an “invisible” smiling picture embedded electronically, to supplement the traditional, neutral one on the identification page.