What Motivates Effort? Evidence and Expert Forecasts∗
What Motivates Effort? Evidence and Expert Forecasts∗ Stefano DellaVigna Devin Pope UC Berkeley and NBER U Chicago and NBER This version: March 15, 2017 Abstract How much do different monetary and non-monetary motivators induce costly effort? Does the effectiveness line up with the expectations of researchers and with results in the literature? We conduct a large-scale real-effort experiment with 18 treatment arms. We examine the effect of (i) standard incentives; (ii) behavioral factors like social preferences and reference dependence; and (iii) non-monetary inducements from psychology. We find that (i) monetary incentives work largely as expected, including a very low piece rate treat- mentwhichdoesnotcrowdouteffort; (ii) the evidence is partly consistent with standard behavioral models, including warm glow, though we do not find evidence of probability weighting; (iii) the psychological motivators are effective, but less so than incentives. We then compare the results to forecasts by 208 academic experts. On average, the experts an- ticipate several key features, like the effectiveness of psychological motivators. A sizeable share of experts, however, expects crowd-out, probability weighting, and pure altruism, counterfactually. As a further comparison, we present a meta-analysis of similar treat- ments in the literature. Overall, predictions based on the literature are correlated with, but underperform, the expert forecasts. ∗We thank Ned Augenblick, Oriana Bandiera, Dan Benjamin, Jordi Blanes-i-Vidal, Patrick Dejarnette, Jon de Quidt, Clayton Featherstone, Judd Kessler, David Laibson, John List, Benjamin Lockwood, Barbara Mellers, Katie Milkman, Don Moore, Sendhil Mullainathan, Victoria Prowse, Jesse Shapiro, Uri Simonsohn, Erik Snowberg, Philipp Strack, Justin Sydnor, Dmitry Taubinsky, Richard Thaler, Mirco Tonin, and Kevin Volpp.
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