The Relation Between Preference and Demand in the Domestic Hen: Does Preference Vary With Price?

ABSTRACT Six hens responded under an increasing Fixed Ratio schedule of reinforcement to assess demand separately for two different food types: wheat and puffed wheat. Demand curves generated showed the least preferred food, puffed wheat, yielded a higher initial (ln L) demand than the more preferred food, wheat. While responding for the more preferred food, wheat, produced lower initial (ln L) demand functions, responding for wheat was maintained to higher increasing FR schedules of reinforcement than was that for puffed wheat. This phenomenon occurred across all six hens. To assess preference between the two food types the hens responded under a two-link concurrent-chain schedule of reinforcement. Under the concurrent-chain schedule of reinforcement there were three conditions, each consisted of a initial link with VI 90-s VI 90-s in effect, and terminal links of FR1, FR8 and FR32. The concurrent-chain schedule was used to examine if or how preference may relate to demand. Preference measures obtained showed wheat was generally preferred to puffed wheat across all prices throughout the preference assessment. As price increased in the terminal link during the preference assessment, preference for wheat became more extreme as did the hens responding. The results suggest that while there is a systematic relation between preference and demand, in that at higher FR values food with higher demand levels is preferred. This does not seem to hold, however, at FR