what follows is a piece Stan Gooch wrote 35 years ago regarding human origins.
‘Chimpanzees and gorillas both have very heavy brow ridges. Gibbons also have these, but to a noticeably lesser extent. Orangs do not have them. The infants of all ape species have them in much less degree than the parents. In fact the young of all primates look a good deal more human than the adults. For my own money, the young of the gibbon look most human of all.
The young of apes look more human because further back in evolutionary time the adult ancestors of these primates were more human. The eighteen-week-old chimpanzee foetus looks quite amazingly human. These creatures have become more ape-like, after an initially closer start to ourselves, an example of devolution. A second, more important point is that young apes look more like us because we have managed to play one of nature’s oldest tricks – that of preserving child-like characteristics into adult life. This process is called neotony and is one of nature’s commonest methods of continuing the evolution of a species, in particular for backing it out of a dead-end. We have, for example, the flat face of the baby chimp, gorilla and gibbon, not the jutting muzzle of the adult. The process of neotony is central to any understanding of man’s evolution, and in particular to my own views.
One last word in favour of gibbons. Bernard Campbell states significantly: ‘The evidence for brachiation in man’s ancestry accumulates.’ Of course, with this statement Campbell does not mean to indicate the gibbon as such. Yet, the gibbon is the master brachiator.’
Taken from –
pages 34-35 of The Neanderthal Question (1977), by Stan Gooch