More words on brain + experience: nowadays there are new imaging techniques which have allowed researchers to SEE that new brain cells, or more accurately new pathways between brain cells, develop as a direct result of experience, so that the proof that the brain can change as a result of learning and experience is made visible. In fact the pathways that develop, themselves depend on prior experience; memories created depend on the significance they have to the person experiencing them. This is all connected to the way brain cells communicate with each other -- how they discharge and send impulses to the next cell in a chain depends on input from yet other cells in the net. Nice stuff, "plasticity of the brain". It is an idea that used to be dismissed.