We can use the following definition of learning to help us understand this concept: learning is a relatively permanent change in behavior or knowledge that comes from experience or training. But what does this really mean? We all "know" things and we can all perform lots of behaviors. But where did they come from? Some things are innate - we are born with the knowledge. But others must be acquired actively. Thus, any knowledge or behavior that we now possess that we were not born with, was somehow "learned". Psychologists have studied learning in a variety of ways, from examining the salivation of dogs in response to meat powder, to how rats press a lever in the pursuit of obtaining some kind of reward, to offering children rewards for doing what is asked of them, to examining how people are able to tie their shoe laces.