When faces are partially obscured or difficult to differentiate, subtle body cues allow people to identify others with surprising accuracy, the Texas researchers said.
The finding may help in the development of person-recognition software and expand the understanding of how humans recognize each other, they said.
"Psychologists and computer scientists have concentrated almost exclusively on the role of the face in person recognition," lead researcher Allyson Rice said. "Our results show that the body can also provide important and sometimes sufficient identity information for person recognition."
In experiments, the researchers asked college-age participants to look at images of two people side-by-side -- in some cases the same person with a different appearance and in other cases two different but similar looking people -- and identify whether the images showed the same person.
Participants were best at discerning whether the images showed the same person when they were provided complete images that showed both the face and body, the researchers found.
Although the subjects reported they were using primarily facial features to identify the subjects, they had in fact spent more time looking at the body whenever the face did not provide enough information to identify the subjects, the researchers found.
"Our work shows that the body can be surprisingly useful for identification, especially when the face fails to provide the necessary identity information," project supervisor Alice O'Toole said.
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