Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 17 March 2006:
Vol. 311. no. 5767, p. 1517
DOI: 10.1126/science.311.5767.1517n
Prev | Table of Contents | Next

This Week in Science

Models of animal decision-making often assume that choices are based on the fitness consequences that each choice yields. Fitness gains, in turn, depend on both the intrinsic properties of the options and the state of the subject at the time of the choice. However, recent studies in humans and other vertebrates have shown that preferences may reflect more closely the subject's state at the time of learning than at the time of choice. Pompilio et al. (p. 1613) now describe similar behavior in an invertebrate. In the desert locust, the state-dependent benefit experienced on acquaintance with a source of reward drove later choices. This finding contrasts with normative theories of choice in biology and economics, which rely on present rather than past benefit and psychological models of reinforcement learning that use absolute reward magnitude rather than state-dependent benefit.




To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)