Experimental tests of dynamically inconsistent time preferences have largely relied on choices over time-dated monetary rewards. Several recent studies have failed to find the standard patterns of present bias. However, such monetary studies contain often-discussed confounds. In this article, we sidestep these confounds and investigate choices over consumption (real effort) in a longitudinal experiment. We pair this effort study with a companion monetary discounting study. We confirm very limited time inconsistency in monetary choices. However, subjects show considerably more present bias in effort. Furthermore, present bias in the allocation of work has predictive power for demand of a meaningfully binding commitment device. Therefore our findings validate a key implication of models of dynamic inconsistency, with corresponding policy implications.

Experimental tests of dynamically inconsistent time preferences have largely relied on choices over time-dated monetary rewards. Several recent studies have failed to find the standard patterns of time inconsistency. However, such monetary studies contain often discussed confounds. In this paper, we sidestep these confounds and investigate choices over consumption (real effort) in a longitudinal experiment. We pair those effort choices with a companion monetary discounting study. We confirm very limited time inconsistency in monetary choices. However, subjects show considerably more present bias in effort. Furthermore, present bias in the allocation of work has predictive power for demand of a meaningfully binding commitment device. Therefore our findings validate a key implication of models of dynamic inconsistency, with corresponding policy implications.

We experimentally investigate the time-inconsistent taste for immediate grati…cation and future-preference misprediction. Across seven weeks, 100 participants choose the number of unpleasant transcription tasks given various wages to complete immediately and at di¤erent future dates. Participants preferred 10-12% fewer tasks in the present compared to any future date, leading to an estimated of 0:83. Comparing predictions with actual immediate-work choices provides evidence against substantial sophistication, with estimates implying that participants understand no more than 24% of their present bias. Finally, we …nd evidence of "projection bias": when decisions were elicited right after completing tasks rather than before, participants wished to complete 4-12% fewer tasks.