abdulhakeem
13-12-04, 07:00 PM
Mon 13 Dec 2004
ANGUS HOWARTH
TONY Blair and Pierce Brosnan would normally be viewed as two distinctly different people.
But the difference between Blair and Bond is not so easy to spot when their faces are morphed together, scientists have revealed.
At different points as images change shape it might be seen as a suave Tony Blair, or a less fetching version of Pierce Brosnan.
That is because however mixed two faces are, the brain attempts to pin a single familiar identity to them.
Researchers at the University College London (UCL) demonstrated the phenomenon by showing volunteers pictures of morphed celebrity faces.
The same pattern was seen when the footballer David Beckham became the Hollywood star Danny DeVito, and when the former prime minister Baroness Margaret Thatcher’s face was transformed into that of the film star Marilyn Monroe using a computer to blend the images.
Dr Pia Rotshtein, from the UCL’s Institute of Neurology, said: "Our study shows that the brain tries to force us to pin a single identity on a face, even if it looks like a mix of two people we know.
"So a face that is 60 per cent Marilyn Monroe and 40 per cent Lady Thatcher will be identified as an older version of Marilyn Monroe, while an image which is 40 per cent Marilyn Monroe and 60 per cent Lady Thatcher will be seen as the sexier side of Lady Thatcher."
Scans showed that the volunteers used three different parts of their brains in a step-by-step process when analysing the faces.
The first, the inferior occipital gyri (IOG), which is located at the back of the brain, picked up on small physical changes in the morphed faces, such as the number of wrinkles.
The second, the right fusiform gyrus (RFG), located just behind the ears, forced the face into a known or unknown category. This area of the brain generalises across different images of the same face and compares them to stored memories, giving rise to a feeling of familiarity. The RFG is responsible for us thinking: "That face rings a bell."
Finally, the anterior temporal cortex (ATC) came into play. It is believed to store facts about people we know, and was more active when volunteers were very familiar with the face they were shown.
If one of these steps breaks down, as in some forms of dementia, people can lose their ability to identify others.
The findings, reported in the on-line issue of the journal Nature Neuroscience, may help scientists find new ways of treating people with "face-blindness", who cannot recognise faces.
Professor Jon Driver, from the Institute of Cognitive Neuroscience at the UCL, said: "Previous studies have found that damage to these areas of the brain can result in the loss of one’s ability to identify people. Some autistic people also struggle with this ability.
"Dementia patients with damage to the ATC can find it difficult to correctly name someone, while people with a form of epilepsy triggered by the RFG might struggle to distinguish between faces, mistakenly believing different faces to belong to the same person.
"Prosopagnosia, or ‘face blindness’, is a rare condition where the brain is unable to process faces normally, and is linked to damage in some or all of these brain regions.
"Someone with prosopagnosia will have difficulty recognising people from their faces, and may have to rely on other cues such as hairstyle, clothes, hand gestures or voice. Some sufferers may not even be able to recognise their own spouse or their own faces in a mirror."
Meanwhile, a patient who is totally blind has surprised scientists by appearing to possess a "sixth sense" that allows him to recognise sad faces.
The 52-year-old man, known as "patient X", suffered two strokes which damaged the brain areas that process visual signals.
As a result, although his eyes and optic nerves are intact, all he can "see" is darkness.
When shown images of shapes such as circles and squares he was only able to make wild guesses about what they were.
But when the patient was asked to identify angry or happy human faces, he did so with an accuracy of 59 per cent - significantly higher than would be expected by chance.
Similar results occurred when he was given the task of distinguishing between sad and happy or fearful and happy faces.
Brain scans showed that when "patient X" looked at faces expressing emotion, a part of his brain called the right amygdala was activated. The small almond-shaped structure is known to respond to non-verbal signs of anger, defensiveness, avoidance and fear.
http://news.scotsman.com/uk.cfm?id=1422102004
ANGUS HOWARTH
TONY Blair and Pierce Brosnan would normally be viewed as two distinctly different people.
But the difference between Blair and Bond is not so easy to spot when their faces are morphed together, scientists have revealed.
At different points as images change shape it might be seen as a suave Tony Blair, or a less fetching version of Pierce Brosnan.
That is because however mixed two faces are, the brain attempts to pin a single familiar identity to them.
Researchers at the University College London (UCL) demonstrated the phenomenon by showing volunteers pictures of morphed celebrity faces.
The same pattern was seen when the footballer David Beckham became the Hollywood star Danny DeVito, and when the former prime minister Baroness Margaret Thatcher’s face was transformed into that of the film star Marilyn Monroe using a computer to blend the images.
Dr Pia Rotshtein, from the UCL’s Institute of Neurology, said: "Our study shows that the brain tries to force us to pin a single identity on a face, even if it looks like a mix of two people we know.
"So a face that is 60 per cent Marilyn Monroe and 40 per cent Lady Thatcher will be identified as an older version of Marilyn Monroe, while an image which is 40 per cent Marilyn Monroe and 60 per cent Lady Thatcher will be seen as the sexier side of Lady Thatcher."
Scans showed that the volunteers used three different parts of their brains in a step-by-step process when analysing the faces.
The first, the inferior occipital gyri (IOG), which is located at the back of the brain, picked up on small physical changes in the morphed faces, such as the number of wrinkles.
The second, the right fusiform gyrus (RFG), located just behind the ears, forced the face into a known or unknown category. This area of the brain generalises across different images of the same face and compares them to stored memories, giving rise to a feeling of familiarity. The RFG is responsible for us thinking: "That face rings a bell."
Finally, the anterior temporal cortex (ATC) came into play. It is believed to store facts about people we know, and was more active when volunteers were very familiar with the face they were shown.
If one of these steps breaks down, as in some forms of dementia, people can lose their ability to identify others.
The findings, reported in the on-line issue of the journal Nature Neuroscience, may help scientists find new ways of treating people with "face-blindness", who cannot recognise faces.
Professor Jon Driver, from the Institute of Cognitive Neuroscience at the UCL, said: "Previous studies have found that damage to these areas of the brain can result in the loss of one’s ability to identify people. Some autistic people also struggle with this ability.
"Dementia patients with damage to the ATC can find it difficult to correctly name someone, while people with a form of epilepsy triggered by the RFG might struggle to distinguish between faces, mistakenly believing different faces to belong to the same person.
"Prosopagnosia, or ‘face blindness’, is a rare condition where the brain is unable to process faces normally, and is linked to damage in some or all of these brain regions.
"Someone with prosopagnosia will have difficulty recognising people from their faces, and may have to rely on other cues such as hairstyle, clothes, hand gestures or voice. Some sufferers may not even be able to recognise their own spouse or their own faces in a mirror."
Meanwhile, a patient who is totally blind has surprised scientists by appearing to possess a "sixth sense" that allows him to recognise sad faces.
The 52-year-old man, known as "patient X", suffered two strokes which damaged the brain areas that process visual signals.
As a result, although his eyes and optic nerves are intact, all he can "see" is darkness.
When shown images of shapes such as circles and squares he was only able to make wild guesses about what they were.
But when the patient was asked to identify angry or happy human faces, he did so with an accuracy of 59 per cent - significantly higher than would be expected by chance.
Similar results occurred when he was given the task of distinguishing between sad and happy or fearful and happy faces.
Brain scans showed that when "patient X" looked at faces expressing emotion, a part of his brain called the right amygdala was activated. The small almond-shaped structure is known to respond to non-verbal signs of anger, defensiveness, avoidance and fear.
http://news.scotsman.com/uk.cfm?id=1422102004