The authors suggest that broad exposure to other races and species in infancy may prevent that loss of ability
Taking it one step further, Pascalis, teh lead study author, noted that even adults who work with primates have trouble recognizing individual animals by their faces.
"Primatologists do recognize monkeys [based] on body posture or spots on fur but can hardly recognize them [based] on faces," he said.
Nature or Nurture?
The question remains: Are our face-processing abilities inborn, learned, or some combination of the two?
"Basically, we have very little knowledge on how an adult brain is made," Pascalis said." We know that part of the [brain's]development is genetically determined and that the environment is going to influence part of its development too. However, we don't know for which cognitive function environmental inputs are crucial nor when they are important."
Previous studies on the role of experience in brain specialization have shown that early visual experience is important to development of face-processing skills.
Wenger, the Penn State neuroscientist, said that there is a hypothesis that, among infants, "the human visual system is specialized in a physical way for the processing of faces," Wenger said.
The alternative to the human brain being hardwired for processing faces "is that we use generalized mechanisms that apply to any visual object, and that over time our face-processing skills become very good, because we get a lot of practice," he continued. "It's an incredibly messy field [of study]. You can probably find almost exactly the same number of studies that argue both sides of the question."
Changing Views of the Brain
"All of these questions intersect with what we've learned in the last 10 to 15 years. Our view of what is modifiable in terms of brain structure has changed dramatically," Wenger said. "Ten years ago the accepted wisdom was that brain maturation was done by adolescence, and that is simply not the view any longer."
Scientists now know that adults can still modify synapses and change the functional characteristics of the cortex by learning a language, taking up a musical instrument, or undertaking other activities that are repeatedly performed.
Wenger's own research, which has been conducted in adults, leans toward a nonhardwired view. His findings suggest that we use generalized vision processes that become highly specialized with particular classes of stimuli.
According to Wenger, we see lots of faces, so we get lots of practice. Therefore, he said, we learn to discern among the types of faces we see the mostwhether they be African, Caucasian, Asian, or even macaque.
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