A behavioral economic analysis of fat appetite in rats

A behavioral economic analysis of rats' consumption of various fat and swee t solutions was conducted in order to assess whether rats' fat appetite is readily modifiable. According to economic demand theory, changes in the pri ce of a reinforcer will produce substantial changes in its consumption unde r conditions in which a substitutable reinforcer is available. Results from income-compensated price changes revealed that sucrose, mineral oil and sa ccharin solutions substituted for a corn oil solution: increases in the pri ce of the corn oil led to large decreases in its consumption and sizable in creases in consumption of these alternatives. On the other hand, plain wate r did not substitute for the corn oil solution: increasing the price of the corn oil did not result in nearly as marked a change in its consumption no r in consumption of the water. Neither the strength of preference for the c orn oil under baseline conditions nor the caloric content of the alternativ e solution predicted whether the alternative reinforcer substituted for the corn oil. Rather, palatability appeared to be a dimension along which subs titution was based. These results suggest that fat appetite is modified whe n palatable alternatives are available, independent of how strongly the fat is preferred. (C) 1998 Academic Press.