In his book on the subject, Sam Lloyd, a former management professor at the SMU Cox School of Business in Dallas, contends that people take "ownership" they have "a stronger investment in the assignment when they know they are responsible for the results and are trusted to use their judgment in obtaining the results."
He uses an interesting analogy to illustrate his point about ownership:
Have you ever driven a rental car? If so, did you wash it before returning it? Probably not. People who own cars are more inclined to wash them regularly. Ownership, whether in things or ideas, promotes accountability.