WHEN people see a face, a particular spot in the brain leaps into action.
This has led some scientists to believe it has a special 鈥渇ace identification
area鈥�. But now researchers say that everything from a Tabasco bottle to a
pelican can light up the same spot. They argue that the area in question
recognises all kinds of subtle visual discrimination, not just faces.
Earlier research into how we see faces produced unexpected results.
杏吧原创s found, for instance, that people might not recognise a picture of
their boss if it were upside down. Similarly, if they saw an image of their
lover鈥檚 eyes slightly further apart than normal, they could not choose the
appropriate mouth from a selection. Such confusion did not happen with other
objects.
To find out more, neuroscientists compared scans of brain activity as people
looked at different things, such as faces and chairs. Looking at faces turned
out to excite a specific spot. For some researchers, this was proof that
recognising a face is an innate human ability located in a special part of the
brain.
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But for Isabel Gauthier of Yale University and her colleagues, the theory did
not ring true. To test it, they used functional magnetic resonance imaging to
see which parts of the brain were active when people did certain tasks. Eight
volunteers were asked to identify pictures of 90 common objects. When shown a
picture of a Ferrari, for instance, they were asked if it was a car, then if it
was a Ferrari. They were asked similar questions about other categories and
sub-categories such as 鈥渂ird鈥攑elican鈥� or 鈥渂ottle鈥擳abasco
产辞迟迟濒别鈥�.
In this month鈥檚 Current Biology, the team reports that when people
identified the sub-categories, their brain patterns were almost identical to
those observed when people looked at faces. 鈥淲e were basically getting the face
area鈥攐r what has been reported by many people as being the face area,鈥�
says Gauthier.
Gauthier thinks earlier studies failed to take account of the fact that
people do not scrutinise chairs as carefully as faces. It is enough to recognise
that a chair is a chair, but because recognising faces is so important socially,
humans are expert at taking in small details about them. 鈥淭hat鈥檚 just what we do
with faces,鈥� says Gauthier. 鈥淚t鈥檚 a useful social cue.鈥�