4 Human research methods for studying operant demand

Human behavior seeks to maximize reinforcement over time. This tendency manifests in several ways, presenting as preferences for immediacy over delay, guarantees over probabilistic outcomes, and maximum consumption as a function of cost. The latter can be conceptualized as the law of demand – changes in consumption occur in accordance with changes in unit price. The extent to which consumption of a commodity persists as prices change depends on myriad variables: environmental shifts, changes in motivation, and the availability of alternative reinforcers, to name a few. The purpose of this chapter is to introduce readers to the concept of operant demand and explore methods of studying demand via human subject research. Historical perspectives have informed the modern understanding and application of human operant demand research, resulting in the introduction of the hypothetical purchase task. Hypothetical purchase tasks have been validated across various applications; these are described in the chapter and inform a purchase task toolkit curated for those interested in conducting their first purchase task study. The chapter concludes by discussing qualitative components of behavioral economic demand research and the impact qualitative research has contributed to improved ecological validity of purchase task methods.