Exponential-growth bias (EGB) is the tendency for individuals to partially neglect compounding of exponential growth. We develop a model wherein biased agents misperceive the intertemporal budget constraint, and derive conditions for overconsumption and dynamic inconsistency. We construct an incentivized measure of EGB in a US-representative population and find substantial bias, with approximately one third of subjects estimated as the fully biased type. The magnitude of the bias is negatively associated with asset accumulation, and does not respond to a simple graphical intervention. (JEL: D03, D11, D12, D14, D18, D91, E21)

We present evidence that intrinsic demand for information about the future is increasing in expected future consumption utility. In the first experiment, subjects may resolve a lottery now or later. The information is useless for decision making, but the larger the reward, the more likely subjects are to pay to resolve the lottery early. In the second experiment, subjects may pay to avoid being tested for herpes simplex virus type 1 (HSV-1) and the more highly feared type 2 (HSV-2). Subjects are three times more likely to avoid testing for HSV-2, suggesting that more aversive outcomes lead to more information avoidance. In a third experiment, subjects make choices about when to get tested for a fictional disease. Some subjects behave in a way consistent with expected utility theory, and others exhibit greater delay of information for more severe diseases. We also find that information choice is correlated with positive affect, ambiguity aversion, and time preference, as some theories predict. Data, as supplemental material, are available at https://doi.org/10.1287/mnsc.2016.2550 . This paper was accepted by Teck-Hua Ho, behavioral economics.

In a nationally representative sample, we predict retirement savings using survey‐based elicitations of exponential‐growth bias (EGB) and present bias (PB). We find that EGB, the tendency to neglect compounding, and PB, the tendency to value the present over the future, are highly significant and economically meaningful predictors of retirement savings. These relationships hold controlling for cognitive ability, financial literacy, and a rich set of demographic controls. We address measurement error as a potential confound and explore mechanisms through which these biases may operate. Back of the envelope calculations suggest that eliminating EGB and PB would increase retirement savings by approximately 12%. (JEL D91, D14)

A large fraction of microbial life on earth exists in complex communities where metabolic exchange is vital. Microbes trade essential resources to promote their own growth in an analogous way to countries that exchange goods in modern economic markets. Inspired by these similarities, we developed a framework based on general equilibrium theory (GET) from economics to predict the population dynamics of trading microbial communities. Our biotic GET (BGET) model provides an a priori theory of the growth benefits of microbial trade, yielding several novel insights relevant to understanding microbial ecology and engineering synthetic communities. We find that the economic concept of comparative advantage is a necessary condition for mutualistic trade. Our model suggests that microbial communities can grow faster when species are unable to produce essential resources that are obtained through trade, thereby promoting metabolic specialization and increased intercellular exchange. Furthermore, we find that species engaged in trade exhibit a fundamental tradeoff between growth rate and relative population abundance, and that different environments that put greater pressure on group selection versus individual selection will promote varying strategies along this growth-abundance spectrum. We experimentally tested this tradeoff using a synthetic consortium of Escherichia coli cells and found the results match the predictions of the model. This framework provides a foundation to study natural and engineered microbial communities through a new lens based on economic theories developed over the past century.

No abstract