What makes one face in the crowd stand out from the others? It may be seeing teeth that makes the difference.
What helps you spot a face in the crowd? Research suggests that it’s an angry or emotional face we tend to register first. A recent study takes it even further suggesting that whether smiling or grimacing, visible teeth seem to make the difference.
The “emotional-face-in-the-crowd effect” relates to a search advantage for faces with a particular emotional expression. Previous research suggested that it was only angry faces that were found faster than neutral, or other, facial expressions. The theory was that responding quickly to negative facial expression is hard-wired in the brain to help you recognize danger and protect yourself. This would be evolutionarily beneficial if you needed to determine a potential threat and respond accordingly in order to survive. But further investigation revealed that in some cases it is the happy faces that had an advantage.
“The research concerned with the face-in-the-crowd effect essentially deals with the question of how we detect social signals of friendly or unfriendly intent in the human face,” said author Gernot Horstmann, PhD, of the Center for Interdisciplinary Research and Department of Psychology at Bielefeld University, Germany. “Our results indicate that, contrary to previous assertions, detection of smiles or frowns is relatively slow in crowds of neutral faces, whereas toothy grins and snarls are quite easily detected.”
Horstmann and his colleagues conducted experiments in an attempt to resolve discrepancies in previous studies that investigated visual search for emotional faces. According to the research team, the inconsistent results with respect to which of the two expressions are found faster — the happy face or the angry face — suggested that the emotional expression category could not be the only important factor determining the face-in- the-crowd effect.
In the experiment, researchers asked subjects to search for a happy or an angry face within a crowd of neutral faces, and measured the search speed. The “search” ended when the subject responded yes or no to the presence of an angry or happy face, depending on the target for that trial. While the search was relatively slow when emotion was signaled with a closed mouth face, the search time was much faster when emotion was signaled with an open mouth and visible teeth. This was the case for both happy and angry faces, and happy faces were found even somewhat faster than angry faces.
The scientists believe this new study may explain the discrepancies found in the literature. “This will probably inspire researchers to clarify whether emotion and, in particular, threat plays an additional, unique role in face detection,” said Horstmann.
