After many scientific tests were done on an early Greek statue, the Getty Museum was about to buy it. However, a small group of experts looked at it and said immediately "It's a fake". Eventually, it was found to be a fake. The question was, how could anyone beat the battery of scientific tests just by looking at it? The sceptics were asked how they did it. One said "It doesn't look old, as if it had been centuries under the ground. Another said "Its fingernails don't look right". Apparently they had all seen something which triggered a doubt. Psychologists thought this might be an ancient mental mechanism which has survival value.