Humans' expertise in recognizing faces may be attributed to their tendency to see people and faces as individuals, suggests a new study.
Vanderbilt University researchers, who led the study, say that the same approach can be learnt and applied to other objects as well.
"This new research adds to the evidence that the brain processes faces differently because of our expertise with them. It also tells us what it is about our experience with faces that leads us to treat them holistically. This knowledge may be useful in the development of training protocols for individuals with difficulties in face perception, such as individuals with autism spectrum disorders," said Isabel Gauthier, an associate professor of Psychology at the university and one of the study's co-authors.
Alan Wong, who completed the study as his doctoral thesis in psychology at Vanderbilt, said: "Our findings suggest that facial expertise does not just develop with any type of experience.
Learning to recognize a set of objects as individuals may work, but categorizing them at a more general level, or learning to manipulate them, would not. We develop different types of expertise in recognizing different objects not just due to their unique appearance, but also because of the types of experience we have had with them."
Currently in press at Psychological Science, the study report highlights the fact that scientists have for decades debated whether humans are better able to recognize faces because they have evolved a brain system dedicated to this task or because they have extensive practice recognizing faces.
The researchers agree that humans recognize faces holistically, which is not how they generally recognize other objects.
They say that an individual finds it almost impossible to attend to only one part of a face and ignore the rest, but he/she may recognize a car by its grill, taillights or branding.
Studies conducted in the past have suggested that people can develop face-like expertise with novel objects, such as cars, and that once that expertise has been developed those objects are also processed holistically.
However, they did not show what was about expertise that produced this holistic effect.
The new study investigated this question by comparing two different types of training regimens with the same novel objects, called Ziggerins. The Ziggerins were created just for the experiment and have no real-world function.
One group learnt to individuate the objects with unique names, much like a person does with other people and faces. Another group learnt to very quickly categorize the objects based on shared structure.
Each group became better than the other at the task on which it was trained, illustrating that different kinds of perceptual expertise can develop for the same objects.
But, only the group that learned to individuate Ziggerins later processed novel Ziggerins holistically, like faces.
"This research indicates that not only is individuation key to our expertise with faces, but that this technique can be quickly applied to other objects. Hallmarks of face-like expertise do not require 10 years, or even 10 hours, of experience to emerge," the authors said.