How do educational psychologists define "motivation"?

How do educational psychologists define "motivation"?

Louis Pugliese (Lecturer in Educational Psychology, CSUN, Certified by the National Board for Professional Teaching Standards) gives expert video advice on: What conditions stimulate learning?; How can I help my child be more motivated in the classroom? and more...

Motivation is an internal drive. Often we look at motivation as the extrinsic things that somebody wants. We learn because we want to get a good job or we go to our job because we want money. But immediately, most of us get up and go to work because we're looking forward to going to work, and immediately most of us attend to a learning task because it has some intrinsic interest. Motivation is often described as the amount that we're invested or interested in the task, how much value it has to us, whether we want to learn to do it, try to do it, and it's also related to whether we think we can do it or not. I would love to be a teenage rock n roll guitar player, but I don't believe I'll be able to do that, so while my desire to do it is strong, my expectation that I'll be successful at it is very low, therefore my motivation is low.