In 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.

Thesis (Ph. D.)--UCLA, 2009. / Vita. Description based on print version record. Includes bibliographical references (leaves 179-202).

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2000. / Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 82-94).

The Cognitive Evaluation Theory explains the outcomes of studies employing Deci's paradigm, but only when used post hoc. A basic assumption is that extrinsic rewards always increase intrinsic motivation for nonhuman subjects. Deci's paradigm was modified for use with 22 rats to test this assumption. Running in an exercise wheel was the intrinsically motivated activity studied. ANCOVA revealed that external rewards increased intrinsic interest on the first day following the cessation of reinforcement (F = 8.32), but on two subsequent days and again a week later, no significant differences between the reward and control groups were evident (F = .29; F = .33; F = 3.70). The assumption was not supported. It was demonstrated that repeated posttest measures are necessary to avoid basing conclusions upon one point along the extinction continuum.