Object orientation fosters reusable software structures. The result is accelerated design and implementation. OOP quickly brings new products and versions to the marketplace. Evidence consistent with the second reason is all around us. We all use packages designed via object oriented analysis and developed via object oriented languages or tools.
Evidence is consistent with the first reason is harder to find.
Whether or not OOP fits more closely with our intuitions is empirically testable, and I don't know of anyone who has performed such a test. If you know of any studies in this area, I'd like to hear from you. This idea, of course, is testable as well. In any event, our intuitions tell us that you'll enjoy this issue. Two articles fit squarely within our object oriented focus.