Intelligence being the characteristic which we consider most 'human', it was inevitable that people searching for our early ancestors should have expected them to be big-brained from an early stage in their development.
So when in 1912 a big-brained skull and an apelike jawbone were 'discovered' together at Piltdown in England, along with fossil animal bones, they were readily accepted as the 'Missing Link' between humans and apes.
'Piltdown Man', however, was actually a skilful forgery using a modern human skull and the jaw of an orang-utan. He bedevilled the study of our ancestry for decades: subsequent discoveries of genuine hominid fossils with small jaws and small brains were for a long time considered suspect because of their divergence from the expected path of human development as exemplified by Piltdown Man.
Gradually, however, the tide of opinion turned and Piltdown Man was no longer considered to have been in the mainstream of human evolution. In 1953 various dating techniques were able to establish the genuine (recent) age of the Piltdown remains and the hoax was unmasked, though to this day the identity and motive of the hoaxer remain a mystery .
