How to spend it: the neural basis of budget effects on cost-benefit decisions of rodent and human consumers

• Applicant: Professor Tobias Kalenscher, Ph.D., since 6/2022
• Subject Area: Biological Psychology and Cognitive Neuroscience
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 417910727

In economics, empirical studies of individual choices are mostly based on field data from samples of human population. Despite significant advances in the field of neuroeconomics, we still know very little about the neural basis of economic choice. Previous studies showed that economic theory accounts well for animal behaviors. These animal models serve as a means to probe elementary principles of microeconomics, as well as an indispensable complement to human research by allowing neurobiological manipulations to be employed. Thus, establishing cross-species research will enable us to fully understand the neural process underlying economic behaviors. To this end, I conducted a series of lesion experiments to explore the neural mechanisms of supply and demand in rat consumers. Rats were trained to trade effort (i.e. nose poking) for rewards: their demand for preferred reward decreased as its price (i.e. number of nose pokes required to get a reward) increased, which is expressed as price effect on demand elasticity. When the budget (i.e. total number of nose pokes available per session) was extended to compensate price increases, animals maintained their original consumption pattern, as shown by smaller price elasticities relative to conditions in which price increase was not compensated. This budget effect implies that rats evaluate effort costs not only by their nominal value (e.g. net effort required to obtain a reward), but also with respect to their purchasing power (e.g., how much reward can be purchased given its price and available budget). Interestingly, I have shown that budget effect on price elasticity was diminished when anterior cingulate cortex (ACC) was damaged, suggesting this region is crucial for animals to integrate budget information into cost-benefit computations. To assess the comparative value of our task, I translated our animal paradigm to a human budget task, and showed that manipulations of effort and budget had similar effects on human consumer behavior. However, despite these findings, it is still unclear 1) how the budget effect on cost-dependent reward valuation is represented in rat ACC neurons, 2) whether behavioral/cognitive process underlying this budget effect is parallel across species. To address these issues, I propose to conduct tetrode recordings in the ACC of rats performing the effort-budget task. In the second experiment, I plan to refine our human task to develop a fully comparable paradigm that allows future comparisons between species, moving beyond the behavioral level. Results of the two experiments will provide new insights and empirical evidence to interpret effort-based cost-benefit decisions under budget constraint in rodents and humans, which are not captured in previous studies, and advance our understanding of the applicability of economic demand theory across species.

• DFG Programme: Research Grants
• Ehemalige Antragstellerin: Dr. Yue Hu, until 6/2022