A team of psychologists at the University of Glasgow, UK, has finally found why people so often have trouble telling those of a different race apart. They have identified the brain mechanism that is responsible for this 'other-race effect', and hope their findings could prove very useful in determining the reliability of eyewitness evidence in criminal trials, reports New Scientist.
Roberto Caldara and colleagues of the University of Glasgow, UK, carried out the research on 24 Caucasian and East Asian volunteers.
The participants were shown pairs of photos, one after another, either of two people of the same racial group - East Asian or Caucasian, or photos of the same person but with two different facial expressions.
At the same time, the brain activity of the volunteers was recorded using electroencephalography (EEG).
EEG measures the electrical activity produced by the firing of neurons in the brain, and when someone sees the same face twice, the EEG pattern is the same every time, although the activity levels is lower the second time.
On the other hand, if the faces are different, then so are the brain activity patterns.
When the volunteers were shown faces of people of a different race than their own, their neurons responded as if they saw the same person, whether that was the case or not.
The results were the same for both Caucasian and East Asian volunteers.
Caldara concluded that this must be 'a universal phenomenon in our perception', and added people who live among people of other races can learn to identify individuals better.
Even if previous studies have identified the brain region responsible for the phenomenon, the mechanisms triggering it were unclear.
The researchers said that the technique could be used to identify unreliable witnesses in criminal trials, because "if a witness has a really clear other-race effect, we could not be sure that they had really recognized a defendant of another race."
John Brigham of Florida State University in Tallahassee sees the technique as fascinating but not fully ready to be used in court.