科学美国人60秒:Clark Kent's Glasses Aided His Anonymity

Ever wonder how the citizens of Metropolis somehow could not recognize Clark Kent once he ditched the glasses and became Superman? Well, now there’s an actual scientific explanation: When a person alters their appearance, even in small ways like adding a pair of glasses, it can indeed lessen the ability of others who do not know that person to recognize his or her face.   

The study is in the journal Applied Cognitive Psychology. [Robin S. S. Kramer and Kay L. Ritchie, Disguising Superman: How Glasses Affect Unfamiliar Face Matching]

Psychologists Robin Kramer and Kay Ritchie from the University of York in the U.K. showed volunteers pictures of unknown people—not celebrities. The photos came from Google Images, and featured people in various poses, with different facial expressions and changing lighting. 

The participants saw two photos at the same time—either two pictures of the same person or a different person in each picture. Three possible pairs of pictures were presented: both people wore glasses; neither person wore glasses; or only one of the pair of people had glasses on. 

Then the researchers asked the volunteers whether the pictures were of the same person or of two different people. 

When the folks in both pictures were in the same condition—either both with glasses or both without—the participants were about 80 percent accurate in telling whether it was the same person or a different person in the two pics. But accuracy fell to 74 percent when glasses were worn in only one of the pictures. 

The researchers noted that the appearance of the eyes may be the most important aspect of facial recognition, so a change to the eyes could be expected reduce recognition. But trained examiners, such as TSA agents, may be less fooled by such simple modifications.  

The researchers concluded their paper by writing [quote]: “While we may still find it hard to believe that the inhabitants of Metropolis are unable to match Clark Kent with the numerous appearances of Superman in newspapers and on television, we can at least understand why Kent has chosen glasses as his aid to anonymity.”

—Erika Beras