Difference in skills to distinguish faces is ingrained in the unique way wherein the mind of every individual perceives the look of another person, states a new study.
In daily life, we recognize faces both holistically and also "analytically", that is, picking out individual parts, such as eyes or nose. But while the brain uses analytical processing for all kinds of objects, cars, houses, animals, "holistic processing is thought to be especially critical to face recognition".
"Face recognition is an important social skill, but not all of us are equally good at it," Jia Liu, the lead researcher from Beijing Normal University, said.
To isolate holistic processing as the key to face recognition, the researchers first measured the ability of study participants, 337 male and female students, to remember whole faces, using a task in which they had to select studied faces and flowers from among unfamiliar ones.
The next two tasks measured performance in tasks that mark holistic processing. The composite-face effect (CFE) shows up when two faces are split horizontally and stuck together.
It's easier to identify the top half-face when it's misaligned with the bottom one than when the two halves are fitted smoothly together, "because our brain automatically combines them to form a new", and unfamiliar, "face".
Liu also said that the other marker of holistic processing is the whole-part effect (WPE). In this one, people are shown a face, then asked to recognize a part of it, say, the nose. They do better when the feature is presented within the whole face than when it stands on its own among other noses: again, we remember the nose integrated into the whole face.
The researchers also assessed participants' general intelligence.
The researchers found that the participants who scored higher on CFE and WPE, that is, who did well in holistic processing, also performed better at the first task of recognizing faces. But there was no link between facial recognition and general intelligence, which is made up of various cognitive processes, a suggestion that face processing is unique.
"Our findings partly explains why some never forget faces, while others misrecognize their friends and relatives frequently," Liu added.
The study has been published in Psychological Science.