Research
My research concerns discounting, the decrease in the subjective value of delayed and probabilistic outcomes, and its role in decision-making across the adult lifespan. This research comprises four lines of work, described below with selected publications.
Research area 01
Age-related differences in discounting
How does discounting differ with age, and what are the sources of these differences?
There is no consensus as to whether, or in which direction, discounting differs with age, and recent meta-analyses have concluded that adult age differences are small at best. These analyses, however, did not systematically take socioeconomic status into account. Our studies of younger and older adults with lower and higher incomes revealed age differences that were modest but systematic: Older adults discounted delayed gains and delayed losses less steeply than younger adults, whereas they discounted probabilistic gains more steeply. Current research examines the sources of these differences and, in particular, the extent to which they reflect people’s financial circumstances.
Selected works
Wan, H. (2026). Age, income, and the discounting of delayed and probabilistic rewards: The roles of financial resources and attribute salience [Doctoral dissertation, Washington University in St. Louis]. Paper
Wan, H., Myerson, J., Green, L., Strube, M. J., & Hale, S. (2026). Age, income, and the discounting of delayed and probabilistic rewards. Frontiers in Psychology, 17, 1765142. Paper
Wan, H., Myerson, J., Green, L., Strube, M. J., & Hale, S. (2025). Age, income, and the discounting of delayed monetary losses. The Journals of Gerontology: Series B, 80(11), gbaf162. Paper
Wan, H., Myerson, J., Green, L., Strube, M. J., & Hale, S. (2024). Age-related differences in delay discounting: Income matters. Psychology and Aging, 39(6), 632–643. Paper
Research area 02
Decision-making in more complicated situations
Can decisions in more complicated situations be predicted from simple choices?
Most of what is known about discounting comes from simple choices in which outcomes differ only in amount and in either delay or probability. Many everyday decisions, however, involve outcomes that are both delayed and probabilistic or that combine gains with losses. We examine whether decisions in these more complicated situations can be predicted from simple choices. When rewards were both delayed and probabilistic, delay discounting was much shallower than simple choices would lead one to expect, and none of three prominent models predicted this delay–probability asymmetry. Current research extends this approach to other kinds of outcomes and to adults of different ages and incomes.
Selected works
Myerson, J., Green, L., Vanderveldt, A., & Wan, H. (2026). Delay–probability asymmetry in discounting: An anomaly in multiattribute choice. Journal of the Experimental Analysis of Behavior, 126(1), e70123. Paper
Wan, H., Myerson, J., & Green, L. Asymmetric conditioning in the discounting of delayed, probabilistic rewards: A test of three combination rules. Manuscript in preparation.
Wan, H., Myerson, J., & Green, L. Delay and probability discounting: From standard to more complex, multi-attribute choice options. Book chapter in preparation.
Research area 03
Measurement of discounting
Do different procedures and measures assess the same construct?
Conclusions regarding individual and group differences in discounting depend on how discounting is measured. We examine whether different procedures and different measures of the degree of discounting assess the same construct. Our studies indicate that they do, both for delayed gains and for delayed losses. We have also developed brief questionnaires that retain the measurement quality of longer ones and whose brevity lends itself to online surveys with large samples.
Selected works
Wan, H., Green, L., & Myerson, J. (2025). Brief assessments of delay discounting: Two-amount monetary choice and delayed losses questionnaires. The Psychological Record, 75, 591–597. Paper
Wan, H., Green, L., & Myerson, J. (2024). Delayed monetary losses: Do different procedures and discounting measures assess the same construct? Behavioural Processes, 222, 105101. Paper
Wan, H., Myerson, J., & Green, L. (2023). Individual differences in degree of discounting: Do different procedures and measures assess the same construct? Behavioural Processes, 208, 104864. Paper
Research area 04
Basic processes of choice
What principles of choice can be established under controlled laboratory conditions?
Research with animals makes it possible to study choice under conditions that can be controlled more precisely than is usually possible in research with humans. In collaborative studies with pigeons and rats, we apply the behavioral-economic concepts used to study human decision-making, such as demand and discounting, to choices involving food, tokens, and social interaction. These studies show that animals’ choices are orderly and well described by quantitative models of demand and discounting, providing a controlled setting in which to evaluate behavioral-economic theory.
Selected works
Wan, H., Tan, L., & Hackenberg, T. D. (2026). Behavioral economic analysis of pigeons’ token accumulation and reinforcer demand in a laboratory-based token economy. Journal of the Experimental Analysis of Behavior, 125(2), e70095. Paper
Oliveira, L., Green, L., Myerson, J., & Wan, H. (2025). Discounting of probabilistic food reinforcement by pigeons. Journal of the Experimental Analysis of Behavior, 124(1), e70042. Paper
Kirkman, C., Wan, H., & Hackenberg, T. D. (2022). A behavioral-economic analysis of demand and preference for social and food reinforcement in rats. Learning and Motivation, 77, 101780. Paper
See the Publications page for the complete list, including data and code repositories.