Well, babies don't learn to stand and walk (and many other skills) from scratch by trial and error. The hard part of constructing a walking machine has already

Well, babies don't learn to stand and walk (and many other skills) from scratch by trial and error. The hard part of constructing a walking machine has already been solved by millions of years of evolution. Indeed, a calf can walk within hours of being born. A human infant might need more time than a calf in part because walking on two legs is harder than walking on four, but much of the difference simply comes down to the fact that humans are born so early that a lot of predetermined brain development has not yet occurred (the muscles and bones are also too weak). The study [1] found that across varying mammalian species, walking is learned a predictable amount of time after conception (as opposed to time after birth). There's a surely a continuum between brain functions that are completely hard wired and completely learned from scratch. I think it's accurate to say that for many functions, learning is used as a form of adaptive refinement to finalize specific predetermined neural programs. But the exact interaction between learning and pre-programming isn't well understood in most cases. [1] http://www.pnas.org/content/106/51/21889.abstract http://www.pnas.org/content/106/51/21889.abstract