Intermittent Reinforcement and the Persistence of Behavior: Experimental Evidence

Whereas economists have made extensive studies of the impact of levels of incentives on behavior, they have paid little attention to the effects of regularity and frequency of incentives. We contrasted three ways of rewarding participants in a real-effort experiment in which individuals had to decide when to exit the situation : a continuous reinforcement schedule (all periods paid) ; a fixed intermittent reinforcement schedule (one out of three periods paid) ; and a random intermittent reinforcement schedule (one out of three periods paid on a random basis). In all treatments, monetary rewards were withdrawn after the same unknown number of periods. Overall, intermittent reinforcement leads to more persistence and higher total effort, while participants in the continuous condition exit as soon as payment stops or decrease effort dramatically. Randomness increases the dispersion of effort, inducing both early exiting and persistence in behavior ; overall, it reduces agents' payoffs. Our interpretation is that, in the presence of regime shifts, both the frequency and the randomness of the reinforcement schedules influence adjustments that participants make across time to their reference points in earnings expectations. This could explain why agents persist in activities although they lose money, such as excess trading in stock markets.Intermittent reinforcement ; ambiguity ; randomness ; incentives ; experiment

Intermittent Reinforcement and the Persistence of Behavior: Experimental Evidence

Whereas economists have made extensive studies of the impact of levels of incentives on behavior, they have paid little attention to the effects of regularity and frequency of incentives. We contrasted three ways of rewarding participants in a real-effort experiment in which individuals had to decide when to exit the situation: a continuous reinforcement schedule (all periods paid); a fixed intermittent reinforcement schedule (one out of three periods paid); and a random intermittent reinforcement schedule (one out of three periods paid on a random basis). In all treatments, monetary rewards were withdrawn after the same unknown number of periods. Overall, intermittent reinforcement leads to more persistence and higher total effort, while participants in the continuous condition exit as soon as payment stops or decrease effort dramatically. Randomness increases the dispersion of effort, inducing both early exiting and persistence in behavior; overall, it reduces agents’ payoffs. Our interpretation is that, in the presence of regime shifts, both the frequency and the randomness of the reinforcement schedules influence adjustments that participants make across time to their reference points in earnings expectations. This could explain why agents persist in activities although they lose money, such as excess trading in stock markets.randomness, ambiguity, intermittent reinforcement, incentives, experiment

Trust under the prospect theory and quasi-hyperbolic preferences: a field experiment in Vietnam

We conduct a field experiment in Vietnamese villages to explore the effect of the prospect theory and of quasi-hyperbolic time preferences parameters on trust and trustworthiness. We find that risk aversion, loss aversion and present bias do not influence trustors’ decisions, but a higher time discounting increases the amount sent in the South of Vietnam and probability weighting decreases it in the North. If time discounting and loss aversion do not influence trustworthiness, we show that more risk averse and less present biased trustees return a higher share of their wealth to the trustors. These results suggest that adopting another perspective than the expected utility theory and the exponential discounting approach of time preferences enables to uncover some channels by which risk and intertemporal time preferences influence trusting behavior in societies

Incentive Effects on Risk Attitude in Small Probability Prospects

Most studies on the role of incentives on risk attitude report data obtained from within-subject experimental investigations. This may however raise an issue of sequentiality of effects as later choices may be influenced by earlier ones. This paper reports instead between-subject results on the effect of monetary stakes on risk attitudes for small probability prospects in a laboratory experiment. Under low stakes, we find the typical risk seeking behavior for small probabilities predicted by the prospect theory. But under high stakes, we provide some evidence that risk seeking behavior is dramatically reduced. This could suggest that utility is not consistently concave over the outcome space, but rather contains a convex section for very small amounts.risk attitude, incentives, decision, experiment

Ambiguous incentives and the persistence of effort: Experimental evidence

International audienceWhen the assignment of incentives is uncertain, we study how the regularity and frequency of rewards and risk attitudes influence participation and effort. We contrast three incentive schemes in a real-effort experiment in which individuals decide when to quit : a continuous incentive scheme and two intermittent ones, fixed and random. In all treatments, we introduce a regime shift by withdrawing monetary rewards after the same unknown number of periods. In such an ambiguous environment, we show that less able and more risk averse players are less persistent in effort. Intermittent incentives lead to a greater persistence of effort, while continuous incentives entail exit as soon as payment stops. Randomness increases both earlier and later exiting. This selection effect in terms of ability and risk attitudes combined with the impact of intermittent rewards on persistence lead to an increase in mean performance after the regime shift when incentives are intermittent

Ontogenic changes in hematopoietic hierarchy determine pediatric specificity and disease phenotype in fusion oncogene-driven myeloid leukemia

Fusion oncogenes are prevalent in several pediatric cancers, yet little is known about the specific associations between age and phenotype. We observed that fusion oncogenes, such as ETO2–GLIS2, are associated with acute megakaryoblastic or other myeloid leukemia subtypes in an age-dependent manner. Analysis of a novel inducible transgenic mouse model showed that ETO2–GLIS2 expression in fetal hematopoietic stem cells induced rapid megakaryoblastic leukemia whereas expression in adult bone marrow hematopoietic stem cells resulted in a shift toward myeloid transformation with a strikingly delayed in vivo leukemogenic potential. Chromatin accessibility and single-cell transcriptome analyses indicate ontogeny-dependent intrinsic and ETO2–GLIS2-induced differences in the activities of key transcription factors, including ERG, SPI1, GATA1, and CEBPA. Importantly, switching off the fusion oncogene restored terminal differentiation of the leukemic blasts. Together, these data show that aggressiveness and phenotypes in pediatric acute myeloid leukemia result from an ontogeny-related differential susceptibility to transformation by fusion oncogenes. SIGNIFICANCE: This work demonstrates that the clinical phenotype of pediatric acute myeloid leukemia is determined by ontogeny-dependent susceptibility for transformation by oncogenic fusion genes. The phenotype is maintained by potentially reversible alteration of key transcription factors, indicating that targeting of the fusions may overcome the differentiation blockage and revert the leukemic state