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The Great Lie Detectors

By Chitra Padmanabhan; Illustration by Sudheer

Believe it or not but it is true. There are people who lose the ability to understand or use words due to brain damage. But they become extremely good at something else. They become experts at spotting liars. By the changing expressions of people's faces and the tone of their voice they can make out lies from truth.

The condition in which people lose their power to understand or words due to brain damage is called aphasia. A study conducted in Massachusetts, USA, has clearly proved that aphasics make good lie detectors.

The Great Lie Detectors, Eureka: Science for Kids: 86_1.gif In the last 100 years, many neurologists, or doctors studying the brain, have mentioned examples of this amazing power of patients suffering from aphasia. Some have even compared an aphasic's powers to that of a dog with an ability to sniff out people who are faking.

Recently, scientists conducted tests to see if all that was said about aphasics was true. They studied the powers of a mixed group of people. Some were normal; others were aphasic. And it was proved clearly that the normal volunteers still got fooled by words. The aphasics were far ahead of them in recognising false speech. The results of the study were reported in the magazine 'Nature'.

Fourteen years ago, famous American neurologist, Dr Oliver Sacks, wrote about his experiences with aphasic patients in a book. The book's name was equally interesting: 'The Man who Mistook His Wife for a Hat'.

Dr Sacks remembered a particular incident in a hospital. Patients from the aphasia ward were watching TV. Their president, Ronald Reagan, was giving a speech. Since he had been a film actor earlier, making a flashy speech was no problem for him. He was trying to put feelings into each and every word of his speech.

But his speech had an opposite effect on the patients. They did not get impressed with him. On the other hand, the entire ward shook with their laughter. The aphasics knew that he did not mean a word of what he was saying. The President was lying!

Many doctors have always seen aphasic patients as people who are not totally normal because they lack the ability to understand words. Dr Sacks saw aphasics as more gifted than normal people. Normal people get carried away by words. An aphasic cannot understand words. But he or she can still understand what is being said. For Dr Sacks, that was an indication of their superior sensitivity.

He said most of the aphasics had this superior understanding. So, while normal people think of aphasic patients as brain damaged, they actually seem to understand human expressions better.