If you would like to read studies on self-paced learning with immediate feedback going back to the 1960s, search for "programmed instruction": http://scholar.go

If you would like to read studies on self-paced learning with immediate feedback going back to the 1960s, search for "programmed instruction": http://scholar.google.com/scholar?q=programmed+instruction http://scholar.google.com/scholar?q=programmed+instruction