Including symbols in license plates improves recall

NEW ORLEANS – Substituting a symbol for a number in a six-character license plate was found to significantly improve short-term recollection as compared to conventional alphanumeric-only designs, according to a presenter here at an American Academy of Optometry-sponsored press conference.

Alan L. Lewis, OD, PhD, FAAO, and colleagues from the New England College of Optometry evaluated the EZ-ID, a proposed license plate design that uses a heart, star, triangle or square in place of a number or letter in a six-character license plate, as a method for making license plates more recallable.

Alan L. Lewis

At the press conference, Lewis shared the impetus for the proposed design change.

“A murder occurred in Massachusetts where a lot of people saw the car, but couldn’t identify the license plate,” he said.

The researchers randomly selected 10 six-character Massachusetts license plates from a sample of cars. Five of the plates were modified to replace one of the two middle characters with a symbol.

Twenty-eight subjects sat 1.5 meters away from a monitor, and 10 different plates were displayed for 3 seconds each, Lewis explained.

“A distractor photo of a president was shown to get them to think about something else, then they were asked to repeat the license plate,” he said.

“Forty-three percent of all plates were correctly identified,” Lewis said. “Sixty-one percent identified more plates with symbols. Only 7% of plates with alphanumerics were correctly identified.”

He said that 53% of plates containing symbols and 33% of plates containing only alphanumerics were completely correctly identified.

“Ninety-six percent of all symbols were correctly recalled,” Lewis said, “and they were always in the right position. This is a great ability to reduce the gamut of potential vehicles with those plates.”

He concluded: “We believe the inclusion of symbols in a six-character license plate increases the recall of a complete license number. We are moving ahead to try to convince legislators to change license plate design.” – by Nancy Hemphill, ELS, FAAO

Disclosure: No products were mentioned that would require financial disclosure.