 Microscopic examination revealed file-marks on the teeth, and it was deduced from this that someone had modified the teeth to a shape more suited to a human diet.The Piltdown Man hoax succeeded so well because, at the time of its discovery, the scientific establishment believed that the large modern brain preceded the modern omnivorous diet, and the forgery provided exactly that evidence.It has also been thought that nationalism and cultural prejudice played a role in the less-than-critical acceptance of the fossil as genuine by some British scientists.