Bell, Mark Cameron.2008-04-102008-04-1020042008-04-10http://hdl.handle.net/1828/547In this thesis, I submit an empirical method for assessing the interests of non-human animals. This method involves attributing interests to animals on the basis of the choices they make between competing commodities/environments and by gauging the amount of energy they are willing to expend in acquiring these alternatives. Outfitted with consumer demand theory I argue that this method not only determines what an animal wants, it also reveals the commodities that the animal judges to be indispensable to its welfare.Animal psychologyMotivation in animals