We're only able to recognize two faces in a crowd at a time, according to research. Researchers said this is true even if the faces belonged to famous people. They believe the latest findings provide insight into the accuracy of eyewitness testimony and treatment using neuropsychological rehabilitation.
The latest study involved two experiments where participants were asked to name a famous politician like Tony Blair and Bill Clinton or celebrities like Mick Jagger and Robbie Williams from a crowd of unfamiliar faces.
Both experiments consisted of a distractor face placed to the side of the screen. However, participants were asked to ignore it.
Results from the first experiment showed that distractor faces were hard to ignore and significantly influenced participants' ability to recognize famous faces.
The second experiment revealed the same findings even when the additional faces surrounding the famous person's face were placed upside down. Researchers said this finding is "surprising" as upside-down faces are harder to recognize and easier to ignore.
Previous findings suggest that humans recognize faces as one whole object or image, and not by looking at different parts (such as lips, ears, and eyes) or local features that together form a face. Researchers said the latest findings suggest that face parts interfere with people's capacity to identify faces.
"People recognize faces automatically as long as they have sufficient capacity to do so, but not when this ability is stretched by the presence of too many faces," said Thoma further. "Face recognition seems to be limited to the amount of face-specific resources or parts and even happens when other faces are shown upside down."