For most of human history, the model for learning was simple: if you wanted to learn something new, you either had to figure it out on your own or apprentice yourself to someone who could show you how to do it.Watch, listen, and try out the new skill; this worked for peasants and royalty, parents and children, blacksmiths and monks. So what changed all that? Massive increases in population began the first change, and the shift from plowshares to factories during the Industrial Revolution brought new models of learning.