Most often, however, the plagiarist has started out with good intentions but hasn't left enough time to do the reading and thinking that the assignment requires, has become desperate, and just wants the whole thing done with. At this point, in one common scenario, the student gets careless while taking notes on a source or incorporating notes into a draft, so the source's words and ideas blur into those of the student, who has neither the time nor the inclination to resist the blurring.
Harvey, G. (2008). Writing with sources: A guide for students (2nd ed.). Cambridge, MA: Hackett Publishing Co.