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Friends with Health Benefits: A Field Experiment
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Abstract
When pursuing goals, we commonly choose between going it alone versus teaming up together. In a field experiment (N=774 undergraduates), we tested the benefits of rewarding individual versus tandem goal pursuit. In a "standard-reward condition", we experimentally offered gym members an individual cash reward each day they visited the gym for four weeks. Participants in a "tandem-reward condition" could earn the same reward, but only if they surmounted an extra hurdle-they had to visit the gym with a friend. Although this additional requirement made it more difficult for participants in the tandem-reward condition to earn equivalent incentives, participants with this extra hurdle visited the gym about 35% more frequently than those earning a standard reward. A follow-up survey suggests that tandem rewards provide non-monetary incentives that change behavior, including increased accountability and enjoyment. Our findings illustrate the advantages of making desired behaviors social to promote follow-through.
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Psychologists have not determined the defining characteristics of extraversion. In four studies, the authors tested the hypothesis that extraversion facets are linked by reward sensitivity. According to this hypothesis, only facets that reflect reward sensitivity should load on a higher order extraversion factor. This model was tested against a model in which sociability links the facets. The authors also tested the generalizability of the model in a diverse sample of participants from 39 nations, and they tested the model using widely used extraversion scales. Results of all studies indicate that only facets that reflect reward sensitivity load on a higher order extraversion factor and that this factor correlates strongly with pleasant affect. Although sociability is undoubtedly an important part of extraversion, these results suggest that extraverts’ sociability may be a by-product of reward sensitivity, rather than the core feature of the trait.
Policy-makers are increasingly turning to behavioural science for insights about how to improve citizens’ decisions and outcomes¹. Typically, different scientists test different intervention ideas in different samples using different outcomes over different time intervals². The lack of comparability of such individual investigations limits their potential to inform policy. Here, to address this limitation and accelerate the pace of discovery, we introduce the megastudy—a massive field experiment in which the effects of many different interventions are compared in the same population on the same objectively measured outcome for the same duration. In a megastudy targeting physical exercise among 61,293 members of an American fitness chain, 30 scientists from 15 different US universities worked in small independent teams to design a total of 54 different four-week digital programmes (or interventions) encouraging exercise. We show that 45% of these interventions significantly increased weekly gym visits by 9% to 27%; the top-performing intervention offered microrewards for returning to the gym after a missed workout. Only 8% of interventions induced behaviour change that was significant and measurable after the four-week intervention. Conditioning on the 45% of interventions that increased exercise during the intervention, we detected carry-over effects that were proportionally similar to those measured in previous research3–6. Forecasts by impartial judges failed to predict which interventions would be most effective, underscoring the value of testing many ideas at once and, therefore, the potential for megastudies to improve the evidentiary value of behavioural science.
Temptation bundling—pairing a pleasurable indulgence with a behavior that provides delayed rewards—combats present bias by making behaviors with delayed benefits more instantly-gratifying. If people are sophisticated and capable of following self-set rules to overcome present bias, they could benefit from learning about temptation bundling. Participants in a four-week exercise-boosting program (N = 6792) received either an audiobook with encouragement to temptation bundle, only an audiobook, or neither an audiobook nor encouragement to temptation bundle. Giving participants audiobooks and encouraging temptation bundling boosted their likelihood of a weekly workout by 10–14% and average weekly workouts by 10–12% during and up to seventeen weeks post-intervention. Relative to giving audiobooks alone, encouraging temptation bundling had a modest positive effect on exercise on the extensive margin. The marginal benefit of encouraging temptation bundling may be small because free audiobooks leak information: Simply providing an audiobook to exercise program participants suggests they should temptation bundle.
Selfish incentives typically outperform prosocial incentives, and customer referral programs frequently use such “selfish” (i.e., sender-benefiting) incentives to incentivize current customers to recruit new customers. However, in two field experiments and a fully incentivized lab experiment, this research finds that “prosocial” (i.e., recipient-benefiting) referral incentives recruit more new customers. Five subsequent experiments test a process account for this effect, identifying two key psychological mechanisms: reputational benefits and action costs. First, at the referral stage, senders (existing customers) anticipate reputational benefits for referring recipients (potential new customers), who receive a reward for signing up. These reputational benefits render recipient-benefiting referrals just as effective as sender-benefiting referrals at the relatively low-cost referral stage. Second, at the uptake stage, recipient-benefiting referrals are more effective than sender-benefiting referrals: recipient-benefiting referrals directly incentivize recipients to sign up, providing a clear reward for an otherwise costly uptake decision. The preponderance of selfish, or sender-benefiting, referral incentives in the marketplace suggests these effects are unanticipated by marketers who design incentive schemes.
For a policy-maker promoting the end of a harmful tradition, conformist social influence is a compelling mechanism. If an intervention convinces enough people to abandon the tradition, this can spill over and induce others to follow. A key objective is thus to activate such spillovers and amplify an intervention’s effects. With female genital cutting as a motivating example, we develop empirically informed analytical and simulation models to examine this idea. Even if conformity pervades decision-making, spillovers can range from irrelevant to indispensable. Our analysis highlights three considerations. First, ordinary forms of individual heterogeneity can severely limit spillovers, and understanding the heterogeneity in a population is essential. Second, although interventions often target samples of the population biased towards ending the harmful tradition, targeting a representative sample is a more robust way to achieve spillovers. Finally, if the harmful tradition contributes to group identity, the success of spillovers can depend critically on disrupting the link between identity and tradition.
In this paper, we use mobile messaging to leverage recipients’ social ties and encourage offline prosocial activities in groups. In particular, we conduct a randomized field experiment with 80,000 blood donors and study how behavioral interventions and economic rewards motivate offline group formation. We find that two commonly used interventions—reminder messages and individual reward—are ineffective in motivating group formation because they do not compensate donors for the cost of bringing friends. In contrast, we find that group reward—a new reward that is contingent on a donor bringing a friend—is effective in motivating group formation. Furthermore, group reward tends to attract different types of donors, especially those who are traditionally less active in online social settings but have more local social ties. Structural estimation further reveals the underlying mechanisms, suggesting that group reward is four times more cost-effective than individual reward in driving total donation. Our study suggests that motivating offline group formation is a promising approach to boost prosocial activities.
The online appendix is available at https://doi.org/10.1287/mnsc.2018.3069 .
This paper was accepted by Chris Forman, information systems.
Significance
Principles guiding decisions that affect both ourselves and others are of prominent importance for human societies. Previous accounts in economics and psychological science have often described decision making as either categorically egoistic or altruistic. Instead, the present work shows that genuine altruism is embedded in context-specific egoistic bias. Participants were willing to both forgo monetary reward to spare the other from painful electric shocks and also to suffer painful electric shocks to secure monetary reward for the other. However, across all trials and conditions, participants accrued more reward and less harm for the self than for the other person. These results characterize human decision makers as egoistically biased altruists, with important implications for psychology, economics, and public policy.
Pursuing personal goals for delayed rewards (e.g., exercising to improve health) often provides consumers with immediate rewards (e.g., a fun workout) in addition to the delayed rewards they receive. With regard to health and academic goals, we find that attending to the immediate rewards of health and academic activities increases persistence in these activities to a greater extent than attending to delayed rewards, even though these activities are selected for the delayed rewards they provide. Specifically, bringing immediate rewards into activity choice—for example, having participants choose the most enjoyable rather than the most useful exercise or the tastier rather than healthier bag of carrots—increases persistence and consumption. Similarly, adding external immediate rewards to activity pursuit—for example, playing music in a high school classroom—increases persistence. Across these studies, immediate rewards are stronger predictors of activity persistence than delayed rewards. This research suggests that marketers and consumers can harness immediate rewards to increase persistence in long-term goals.
Influencing behavior change is an ongoing challenge in psychology, economics, and consumer behavior research. Building on previous work on commitment, self-signaling, and the principle of consistency, a large, intensive field experiment (N = 2,416) examined the effect of hotel guests’ commitment to practice environmentally friendly behavior during their stay. Notably, commitment was symbolic—guests were unaware of the experiment and of the fact that their behavior would be monitored, which allowed them to exist in anonymity and behave as they wish. When guests made a brief but specific commitment at check-in, and received a lapel pin to symbolize their commitment, they were over 25% more likely to hang at least one towel for reuse, and this increased the total number of towels hung by over 40%. This research highlights how a small, carefully planned intervention can have a significant impact on behavior. Theoretical and practical implications for motivating desired behavior are discussed.
We introduce and evaluate the effectiveness of temptation bundling—a method for simultaneously tackling two types of self-control problems by harnessing consumption complementarities. We describe a field experiment measuring the impact of bundling instantly gratifying but guilt-inducing “want” experiences (enjoying page-turner audiobooks) with valuable “should” behaviors providing delayed rewards (exercising). We explore whether such bundles increase should behaviors and whether people would pay to create these restrictive bundles. Participants were randomly assigned to a full treatment condition with gym-only access to tempting audio novels, an intermediate treatment involving encouragement to restrict audiobook enjoyment to the gym, or a control condition. Initially, full and intermediate treatment participants visited the gym 51% and 29% more frequently, respectively, than control participants, but treatment effects declined over time (particularly following Thanksgiving). After the study, 61% of participants opted to pay to have gym-only access to iPods containing tempting audiobooks, suggesting demand for this commitment device.
This paper was accepted by Uri Gneezy, behavioral economics.
When people encounter problems in translating their goals into action (e.g., failing to get started, becoming distracted, or falling into bad habits), they may strategically call on automatic processes in an attempt to secure goal attainment. This can be achieved by plans in the form of implementation intentions that link anticipated critical situations to goal-directed responses ("Whenever situation
x arises, I will initiate the goal-directed response
y!"). Implementation intentions delegate the control of goal-directed responses to anticipated situational cues, which (when actually encountered) elicit these responses automatically. A program of research demonstrates that implementation intentions further the attainment of goals, and it reveals the underlying processes. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
In order to mobilise action against a social problem, public service communicators often include normative information in their persuasive appeals. Such messages can be either effective or ineffective because they can normalise either desirable or undesirable conduct. To examine the implications in an environmental context, visitors to Arizona's Petrified Forest National Park were exposed to messages that admonished against the theft of petrified wood. In addition, the messages conveyed information either about descriptive norms (the levels of others' behaviour) or injunctive norms (the levels of others' disapproval) regarding such thievery. Results showed that focusing message recipients on descriptive normative information was most likely to increase theft, whereas focusing them on injunctive normative information was most likely to suppress it. Recommendations are offered for optimising the impact of normative messages in situations characterised by objectionable levels of undesirable conduct. After decades of debate concerning their causal impact, (e.g.
We evaluate the results of a field experiment designed to measure the effect of prompts to form implementation intentions on realized behavioral outcomes. The outcome of interest is influenza vaccination receipt at free on-site clinics offered by a large firm to its employees. All employees eligible for study participation received reminder mailings that listed the times and locations of the relevant vaccination clinics. Mailings to employees randomly assigned to the treatment conditions additionally included a prompt to write down either (i) the date the employee planned to be vaccinated or (ii) the date and time the employee planned to be vaccinated. Vaccination rates increased when these implementation intentions prompts were included in the mailing. The vaccination rate among control condition employees was 33.1%. Employees who received the prompt to write down just a date had a vaccination rate 1.5 percentage points higher than the control group, a difference that is not statistically significant. Employees who received the more specific prompt to write down both a date and a time had a 4.2 percentage point higher vaccination rate, a difference that is both statistically significant and of meaningful magnitude.
Background:
Smoking is the leading preventable cause of premature death in the United States. Previous studies of financial incentives for smoking cessation in work settings have not shown that such incentives have significant effects on cessation rates, but these studies have had limited power, and the incentives used may have been insufficient.
Methods:
We randomly assigned 878 employees of a multinational company based in the United States to receive information about smoking-cessation programs (442 employees) or to receive information about programs plus financial incentives (436 employees). The financial incentives were $100 for completion of a smoking-cessation program, $250 for cessation of smoking within 6 months after study enrollment, as confirmed by a biochemical test, and $400 for abstinence for an additional 6 months after the initial cessation, as confirmed by a biochemical test. Individual participants were stratified according to work site, heavy or nonheavy smoking, and income. The primary end point was smoking cessation 9 or 12 months after enrollment, depending on whether initial cessation was reported at 3 or 6 months. Secondary end points were smoking cessation within the first 6 months after enrollment and rates of participation in and completion of smoking-cessation programs.
Results:
The incentive group had significantly higher rates of smoking cessation than did the information-only group 9 or 12 months after enrollment (14.7% vs. 5.0%, P<0.001) and 15 or 18 months after enrollment (9.4% vs. 3.6%, P<0.001). Incentive-group participants also had significantly higher rates of enrollment in a smoking-cessation program (15.4% vs. 5.4%, P<0.001), completion of a smoking-cessation program (10.8% vs. 2.5%, P<0.001), and smoking cessation within the first 6 months after enrollment (20.9% vs. 11.8%, P<0.001).
Conclusions:
In this study of employees of one large company, financial incentives for smoking cessation significantly increased the rates of smoking cessation. (ClinicalTrials.gov number, NCT00128375.)
Psychologists have not determined the defining characteristics of extraversion. In four studies, the authors tested the hypothesis that extraversion facets are linked by reward sensitivity. According to this hypothesis, only facets that reflect reward sensitivity should load on a higher order extraversion factor. This model was tested against a model in which sociability links the facets. The authors also tested the generalizability of the model in a diverse sample of participants from 39 nations, and they tested the model using widely used extraversion scales. Results of all studies indicate that only facets that reflect reward sensitivity load on a higher order extraversion factor and that this factor correlates strongly with pleasant affect. Although sociability is undoubtedly an important part of extraversion, these results suggest that extraverts' sociability may be a by-product of reward sensitivity, rather than the core feature of the trait.
Some of the most fundamental questions concerning our evolutionary origins, our social relations, and the organization of society are centred around issues of altruism and selfishness. Experimental evidence indicates that human altruism is a powerful force and is unique in the animal world. However, there is much individual heterogeneity and the interaction between altruists and selfish individuals is vital to human cooperation. Depending on the environment, a minority of altruists can force a majority of selfish individuals to cooperate or, conversely, a few egoists can induce a large number of altruists to defect. Current gene-based evolutionary theories cannot explain important patterns of human altruism, pointing towards the importance of both theories of cultural evolution as well as gene-culture co-evolution.
This review covers recent developments in the social influence literature, focusing primarily on compliance and conformity research published between 1997 and 2002. The principles and processes underlying a target's susceptibility to outside influences are considered in light of three goals fundamental to rewarding human functioning. Specifically, targets are motivated to form accurate perceptions of reality and react accordingly, to develop and preserve meaningful social relationships, and to maintain a favorable self-concept. Consistent with the current movement in compliance and conformity research, this review emphasizes the ways in which these goals interact with external forces to engender social influence processes that are subtle, indirect, and outside of awareness.
The Day Reconstruction Method (DRM) assesses how people spend their time and how they experience the various activities and settings of their lives, combining features of time-budget measurement and experience sampling. Participants systematically reconstruct their activities and experiences of the preceding day with procedures designed to reduce recall biases. The DRM's utility is shown by documenting close correspondences between the DRM reports of 909 employed women and established results from experience sampling. An analysis of the hedonic treadmill shows the DRM's potential for well-being research.
Download link at: http://sitemaker.umich.edu/norbert.schwarz/day_reconstruction_method__time_use____well-being
We designed a commitment savings product for a Philippine bank and implemented it using a randomized control methodology.
The savings product was intended for individuals who want to commit now to restrict access to their savings, and who were
sophisticated enough to engage in such a mechanism. We conducted a baseline survey on 1777 existing or former clients of a
bank. One month later, we offered the commitment product to a randomly chosen subset of 710 clients; 202 (28.4 percent) accepted
the offer and opened the account. In the baseline survey, we asked hypothetical time discounting questions. Women who exhibited
a lower discount rate for future relative to current trade-offs, and hence potentially have a preference for commitment, were
indeed significantly more likely to open the commitment savings account. Mter twelve months, average savings balances increased
by 81 percentage points for those clients assigned to the treatment group relative to those assigned to the control group.
We conclude that the savings response represents a lasting change in savings, and not merely a short-term response to a new
product.
Consumers’ lives are filled with myriad behaviors that can be successfully executed with minimal attention. Many such low-attention behaviors benefit from persistence but are often not performed long enough (e.g., hygiene, exercise). The current work examines consumer persistence-failures through an attentional lens. Specifically, drawing on boredom and resource-matching frameworks, we suggest one key driver of poor consumer persistence is that many behaviors demand less attention than consumers have available, leaving excess attention that leads to boredom and premature abandonment. The current research thus proposes an attention-matching framework for persistence and suggests that concurrently performing a task that engages excess attention will improve the match between attentional demands and available resources, thereby increasing persistence. Five experiments across a range of low-attention behaviors (e.g., toothbrushing, coordination exercise) demonstrate that concurrently performing a task that occupies excess attention (e.g., reading, listening), delays boredom and increases persistence. Moreover, two important boundary conditions arise. First, the focal behavior must require minimal attention, leaving excess attention available to attend to the tangential task. Second, the tangential task must engage excess attention without exceeding attentional capacity. This research provides important theoretical and practical contributions, offering the potential to improve consumer well-being by increasing persistence in low-attention behaviors.
Economic incentives are a promising approach for improving health behavior but have been limited by their short-lived benefits. In this manuscript, we examine whether coupling economic incentives with motivational tools provided by health wearables can address this limitation and drive longer-term changes in health behavior. We focus on “gain-loss” incentive schemes that offer both an economic reward for goal attainment and a penalty for failure to meet a goal. In an experiment conducted on individuals wearing Fitbit wearables, we find that gain-loss incentives can drive increases in physical activity but are limited by the element of choice. Specifically, we find modest and short-lived increases in physical activity for those provided the choice of gain-loss incentives. The subpar benefits for this group seem to emerge because those who benefit most from these schemes do not opt into them when they are voluntary. In contrast, we find significant and persistent increases in physical activity for those assigned (oftentimes against their preference) to the same gain-loss incentives. These individuals recorded ∼2,000 additional steps daily during the incentive period, and benefits persisted for six months after incentives ended. Critically, the persistent gains to this group were driven by individuals who also utilized the wearable’s goal-setting tool. Our results suggest that a novel approach toward motivating sustained changes in health behavior couples aggressive incentive schemes that jolt individuals out of their comfort zone in the short term with motivational tools built into health wearables that help individuals sustain healthy behavior after economic incentives end.
This paper was accepted by Kartik Hosanagar, information systems.
Habits involve regular, cue-triggered routines. In a field experiment, we tested whether incentivizing exercise routines—paying participants each time they visit the gym within a planned, daily two-hour window—leads to more persistent exercise than offering flexible incentives—paying participants each day they visit the gym, regardless of timing. Routine incentives generated fewer gym visits than flexible incentives, both during our intervention and after incentives were removed. Even among subgroups that were experimentally induced to exercise at similar rates during our intervention, recipients of routine incentives exhibited a larger decrease in exercise after the intervention than recipients of flexible incentives.
This paper was accepted by Yan Chen, decision analysis.
A growing number of firms use incentive programs to encourage healthy behaviors, but there is little evidence about how such incentives should be structured over time. We explore this issue using a large field experiment that incentivized employees of a Fortune 500 company to use their workplace gym. We compare the effectiveness of a treatment with constant incentives over 8 weeks to two treatments that varied incentives over time. One variable treatment featured front-loaded incentives, which could, in theory, help procrastinators overcome startup costs to joining an incentive program. We find, however, that the front-loaded incentive did not increase participation on the extensive margin relative to the constant incentive and was less effective in sustaining exercise over time. The second variable incentive was designed to leverage short-term habit formation by turning incentives on and off over a longer period of time. This novel sporadic incentive showed slightly stronger effects than the constant incentive. We discuss how the nature of habit-formation processes affects the relative benefits of consistent versus periodic incentives.
This paper was accepted by Uri Gneezy, behavioral economics.
Recent large-scale randomized experiments find that helping people form implementation intentions by asking when and where they plan to act increases one-time actions, such as vaccinations, preventative screenings and voting. We investigate the effect of a simple scalable planning intervention on a repeated behavior using a randomized design involving 877 subjects at a private gym. Subjects were randomized into i) a treatment group who selected the days and times they intended to attend the gym over the next two weeks or ii) a control group who instead recorded their days of exercise in the prior two weeks. In contrast to recent studies, we find that the planning intervention did not have a positive effect on behavior. We observe a tightly estimated null effect even though the majority of subjects believed that planning is helpful and despite clear evidence that they engaged with the planning process.
Significance
With three billion people subsisting on the equivalent of $2.50 per day, alleviating poverty is one of the most urgent challenges facing the world today. One solution to this problem has been to encourage the growth of small enterprises through microlending. A successful innovation is represented by Kiva.org , which matches citizen lenders with low-income entrepreneurs in developing countries. To increase prosocial lending, we use a large-scale field experiment and machine-learning methods to recommend lending teams to lenders. We find that lenders who join a team contribute significantly more compared with those who do not. Our results suggest team recommendation can be an effective and low-cost behavioral mechanism to increase charitable contributions.
Although observers of human behavior have long been aware that people regularly struggle with internal conflict when deciding whether to behave responsibly or indulge in impulsivity, psychologists and economists did not begin to empirically investigate this type of want/should conflict until recently. In this article, we review and synthesize the latest research on want/should conflict, focusing our attention on the findings from an empirical literature on the topic that has blossomed over the last 15 years. We then turn to a discussion of how individuals and policy makers can use what has been learned about want/should conflict to help decision makers select far-sighted options. © 2008, Association for Psychological Science. All rights reserved.
Much of the theory in personnel economics relates to effects of monetary incentives on output, but the theory was untested because appropriate data were unavailable. A new data set for the Safelite Glass Corporation tests the predictions that average productivity will rise, the firm will attract a more able workforce, and variance in output across individuals at the firm will rise when it shifts to piece rates. In Safelite, productivity effects amount to a 44-percent increase in output per worker. This firm apparently had selected a suboptimal compensation system, as profits also increased with the change.
We investigate the effects of team competition on pro-social lending activity on Kiva.org, the first microlending website to match lenders with entrepreneurs in developing countries. Using naturally occurring field data, we find that lenders who join teams contribute 1.2 more loans ($30–$42) per month than those who do not. To further explore factors that differentiate successful teams from dormant ones, we run a large-scale randomized field experiment ( ) by posting forum messages. Compared to the control, we find that lenders make significantly more loans when exposed to a goal-setting and coordination message, whereas goal-setting alone significantly increases lending activities of previously inactive teams. Our findings suggest that goal-setting and coordination are effective mechanisms to increase pro-social behavior in teams.
Unhealthy behaviors are responsible for a large proportion of health care costs and poor health outcomes.1 Surveys of large employers regularly identify unhealthy behaviors as the most important challenge to affordable benefits coverage. For this reason, employers increasingly leverage incentives to encourage changes in employees’ health-related behaviors. According to one survey, 81% of large employers provide incentives for healthy behavior change.2 In this Viewpoint, we discuss the potential and limitations of an approach that behavioral science research has shown can be used to influence health behaviors but that is distinct from incentives: the use of commitment devices (Table).3
Treatment for tobacco dependence is not available in many low-resource settings, especially in developing countries.
To test the impact of a novel mix of monetary and social incentives on smoking abstinence in rural communities of Thailand.
An RCT of commitment contracts and team incentives for rural smokers to quit smoking. Smokers were not blinded to treatment status, although the assessor of the biochemical urine test was.
All adult smokers living in the study area were eligible to participate; 215 adult smokers from 42 villages in Nakhon Nayok province, Thailand, participated. Fourteen smokers who lacked teammates were dropped.
A total of 201 smokers were assigned to a two-person team, and then randomly assigned by team (in a 2:1 ratio) with computer-generated random numbers to receive smoking-cessation counseling (control group) or counseling plus offer of a commitment contract, team incentives, and text message reminders for smoking cessation at 3 months (intervention group).
The primary outcome was biochemically verified 7-day abstinence at 6 months, assessed on an intention-to-treat basis. Secondary outcomes include study participation, biochemically verified abstinence at 3 months, self-reported abstinence at 14 months, and the incremental cost per quitter of the intervention, nicotine gum, and varenicline in Thailand. Data were collected in 2010-2011 and analyzed in 2012.
The trial enrolled 215 (10.5%) of 2055 smokers. The abstinence rate was 46.2% (61/132) in the intervention group and 14.5% (10/69) in the control group (adjusted OR 7.5 [3.0-18.6]) at 3 months; 44.3% (58/131) and 18.8% (13/69) at the primary end point of 6 months (adjusted OR 4.2 [1.8-9.7]); and 42.0% (55/131) and 24.6% (17/69) at 14 months (adjusted OR 2.2 [1.0-4.8]). The purchasing power parity-adjusted incremental cost per quitter from the intervention is $281 (95% CI=$187, $562), less than for nicotine gum ($1780, 95% CI=$1414, $2401) or varenicline ($2073, 95% CI=$1357, $4388) in Thailand.
The intervention enhanced abstinence by 91%-136% at 6 months, relative to the control group, although self-reports at 14 months suggest tapering of the treatment effect. The intervention may offer a viable, cost-effective alternative to current smoking-cessation approaches in low-resource settings.
This study is registered at ClinicalTrials.gov NCT01311115.
We implement a gym-attendance incentive intervention and elicit subjects' predictions of their postintervention attendance. We find that subjects greatly overpredict future attendance, which we interpret as evidence of partial naiveté with respect to present bias. We find a significant postintervention attendance increase, which we interpret as habit formation, and which subjects appear not to predict ex ante. These results are consistent with a model of projection bias with respect to habit formation. Neither the intervention incentives, nor the small posttreatment incentives involved in our elicitation mechanism, appear to crowd out existing intrinsic motivation. The combination of naiveté and projection bias in gym attendance can help to explain limited take-up of commitment devices by dynamically inconsistent agents, and points to new forms of contracts. Alternative explanations of our results are discussed.
Data, as supplemental material, are available at http://dx.doi.org/10.1287/mnsc.2014.2091 .
This paper was accepted by Uri Gneezy, behavioral economics.
Domestic attempts to use financial incentives for teachers to increase student achievement have been ineffective. In this paper, we demonstrate that exploiting the power of loss aversion—teachers are paid in advance and asked to give back the money if their students do not improve sufficiently—increases math test scores between 0.201 (0.076) and 0.398 (0.129) standard deviations. This is equivalent to increasing teacher quality by more than one standard deviation. A second treatment arm, identical to the loss aversion treatment but implemented in the standard fashion, yields smaller and statistically insignificant results. This suggests it is loss aversion, rather than other features of the design or population sampled, that leads to the stark differences between our findings and past research.
Rapidly growing health-care costs have fueled interest in using financial incentives to improve health behaviors. Most of the research on financial incentives outside of clinical studies has been observational, limiting our ability to make causal inferences on their effectiveness. The few carefully-designed studies have generally found little lasting effect on behavior after the incentive program ended. We report on a large field experiment with employees of a Fortune 500 company which offered incentives for using the company gym. In addition to understanding the effects of incentives alone, we investigate a novel approach to generate lasting behavior change using self-funded commitment contracts. At the end of incentive period, half of the incentive group were offered the opportunity to create a self-funded commitment contract to motivate their own behavior. Workers responded strongly during the incentive period, doubling their rate of use of the company gym. After the incentive period ended, we find that those offered incentives only continued to attend at higher rates, but the effect was quite modest in magnitude. The availability of a commitment contract, however, substantially improved the long-run effects of the incentive program both during the commitment period and well beyond, offering a promising new approach to increasing the long-run effect of incentive programs.Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.
A defining aspect of human cooperation is the use of sophisticated indirect reciprocity. We observe others, talk about others, and act accordingly. We help those who help others, and we cooperate expecting that others will cooperate in return. Indirect reciprocity is based on reputation, which spreads by communication. A crucial aspect of indirect reciprocity is observability: reputation effects can support cooperation as long as peoples' actions can be observed by others. In evolutionary models of indirect reciprocity, natural selection favors cooperation when observability is sufficiently high. Complimenting this theoretical work are experiments where observability promotes cooperation among small groups playing games in the laboratory. Until now, however, there has been little evidence of observability's power to promote large-scale cooperation in real world settings. Here we provide such evidence using a field study involving 2413 subjects. We collaborated with a utility company to study participation in a program designed to prevent blackouts. We show that observability triples participation in this public goods game. The effect is over four times larger than offering a $25 monetary incentive, the company's previous policy. Furthermore, as predicted by indirect reciprocity, we provide evidence that reputational concerns are driving our observability effect. In sum, we show how indirect reciprocity can be harnessed to increase cooperation in a relevant, real-world public goods game.
Chinese translation
Data on the effectiveness of employer-sponsored financial incentives for employee weight loss are limited.
To test the effectiveness of 2 financial incentive designs for promoting weight loss among obese employees.
Randomized, controlled trial. (ClinicalTrials.gov: NCT01208350)
Children's Hospital of Philadelphia.
105 employees with a body mass index between 30 and 40 kg/m2.
24 weeks of monthly weigh-ins (control group; n = 35); individual incentive, designed as $100 per person per month for meeting or exceeding weight-loss goals (n = 35); and group incentive, designed as $500 per month split among participants within groups of 5 who met or exceeded weight-loss goals (n = 35).
Weight loss after 24 weeks (primary outcome) and 36 weeks and changes in behavioral mediators of weight loss (secondary outcomes).
Group-incentive participants lost more weight than control participants (mean between-group difference, 4.4 kg [95% CI, 2.0 to 6.7 kg]; P < 0.001) and individual-incentive participants (mean between-group difference, 3.2 kg [CI, 0.9 to 5.5 kg]; P = 0.008). Twelve weeks after incentives ended and after adjustment for 3-group comparisons, group-incentive participants maintained greater weight loss than control group participants (mean between-group difference, 2.9 kg [CI, 0.5 to 5.3 kg]; P = 0.016) but not greater than individual-incentive participants (mean between-group difference, 2.7 kg [CI, 0.4 to 5.0 kg]; P = 0.024).
Single employer and short follow-up.
A group-based financial incentive was more effective than an individual incentive and monthly weigh-ins at promoting weight loss among obese employees at 24 weeks.
National Institute on Aging.
The laboratory experiments were designed to examine the effects of commitment to a performance goal on the level of effort exerted to achieve the goal. In both experiments, college students worked on two memorization tasks and, after receiving performance feedback on the first task, commitment to either an easy or a more difficult goal for the second task was varied. In the first experiment, goal commitment was manipulated either by giving the students perceived choice over setting their goal or by assigning them to one of the two goal levels. In the second experiment, goal commitment was manipulated by publicly identifying students' goals or by keeping the goals private. To assess effort, participants were allowed to spend as little or as much time as they desired studying for the second task. In both experiments, the commitment manipulations (high choice or public identification) led to significantly greater persistence in studying, regardless of the goal level. In addition, high-commitment subjects tended to be more successful in reaching their goals than low-commitment subjects. These experiments suggest that commitment to a goal has motivational properties that prompt an increase in effort.
Strong evidence shows that physical inactivity increases the risk of many adverse health conditions, including major non-communicable diseases such as coronary heart disease, type 2 diabetes, and breast and colon cancers, and shortens life expectancy. Because much of the world's population is inactive, this link presents a major public health issue. We aimed to quantify the eff ect of physical inactivity on these major non-communicable diseases by estimating how much disease could be averted if inactive people were to become active and to estimate gain in life expectancy at the population level.
For our analysis of burden of disease, we calculated population attributable fractions (PAFs) associated with physical inactivity using conservative assumptions for each of the major non-communicable diseases, by country, to estimate how much disease could be averted if physical inactivity were eliminated. We used life-table analysis to estimate gains in life expectancy of the population.
Worldwide, we estimate that physical inactivity causes 6% (ranging from 3·2% in southeast Asia to 7·8% in the eastern Mediterranean region) of the burden of disease from coronary heart disease, 7% (3·9-9·6) of type 2 diabetes, 10% (5·6-14·1) of breast cancer, and 10% (5·7-13·8) of colon cancer. Inactivity causes 9% (range 5·1-12·5) of premature mortality, or more than 5·3 million of the 57 million deaths that occurred worldwide in 2008. If inactivity were not eliminated, but decreased instead by 10% or 25%, more than 533 000 and more than 1·3 million deaths, respectively, could be averted every year. We estimated that elimination of physical inactivity would increase the life expectancy of the world's population by 0·68 (range 0·41-0·95) years.
Physical inactivity has a major health eff ect worldwide. Decrease in or removal of this unhealthy behaviour could improve health substantially.
None.
Voter turnout theories based on rational self-interested behavior generally fail to predict significant turnout unless they account for the utility that citizens receive from performing their civic duty. We distinguish between two aspects of this type of utility, intrinsic satisfaction from behaving in accordance with a norm and extrinsic incentives to comply, and test the effects of priming intrinsic motives and applying varying degrees of extrinsic pressure. A large-scale field experiment involving several hundred thousand registered voters used a series of mailings to gauge these effects. Substantially higher turnout was observed among those who received ailings promising to publicize their turnout to their household or their neighbors. These findings demonstrate the profound importance of social pressure as an inducement to political participation.
We measure how receiving information about coworkers’ savings behavior affects recipients’ savings choices. Low-saving employees were sent a simplified 401(k) plan enrollment or contribution increase form. A randomized subset of forms included information on the (high) fraction of coworkers either participating in or contributing at least 6% of pay to the plan. We document an oppositional reaction: peer information decreased the savings of (unionized) recipients who were not eligible for automatic enrollment in the 401(k). We find no significant evidence that peer information altered the savings decisions of recipients who had previously opted out of automatic 401(k) enrollment.
This paper estimates social effects of incentivizing people in teams. In two field experiments featuring exogenous team formation and opportunities for repeated social interactions, we find large team effects that operate through social channels. The team compensation system induced agents to choose effort as if they valued a marginal dollar of compensation for their teammate from two-thirds as much (in one study) to twice as much as they valued a dollar of their own compensation (in the other study). We conclude that social effects of monetary team incentives exist and can induce effort at lower cost than through direct individual payment.Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.
This paper evaluates a pilot program run by a company called OPOWER, previously known as Positive Energy, to mail home energy reports to residential utility consumers. The reports compare a household’s energy use to that of its neighbors and provide energy conservation tips. Using data from randomized natural field experiment at 80,000 treatment and control households in Minnesota, I estimate that the monthly program reduces energy consumption by 1.9 to 2.0 percent relative to baseline. In a treatment arm receiving reports each quarter, the effects decay in the months between letters and again increase upon receipt of the next letter. This suggests either that the energy conservation information is not useful across seasons or, perhaps more interestingly, that consumers’ motivation or attention is malleable and non-durable. I show that “profiling,” or using a statistical decision rule to target the program at households whose observable characteristics suggest larger treatment effects, could substantially improve cost effectiveness in future programs. The effects of this program provide additional evidence that non-price “nudges” can substantially affect consumer behavior.
Can incentives be effective when trying to encourage the development of good habits? We investigate the effect of paying people a non-trivial amount of money to attend an exercise facility a number of times during a one-month period. In two separate studies, we find that doing so leads to a large and significant increase in the average post-intervention attendance level relative to the control group. This result is entirely driven by the impact on people who did not previously attend the gym on a regular basis, as the average attendance rates for people who had already been using the gym regularly are either unchanged or diminished. In our second study, we also obtain biometric evidence that this intervention improves important health indicators such as weight, waist size, and pulse rate. Thus, even though personal incentives to exercise are already in place, it appears that providing financial incentive to attend the gym regularly for a month serves as a catalyst to get some people past the threshold of actually getting started with an exercise regimen. We argue that there is scope for financial intervention in habit formation, particularly in the area of health.
Departures from self-interest in economic experiments have recently inspired models of “social preferences.” We design a range
of simple experimental games that test these theories more directly than existing experiments. Our experiments show that subjects
are more concerned with increasing social welfare—sacrificing to increase the payoffs for all recipients, especially low-payoff
recipients—than with reducing differences in payoffs (as supposed in recent models). Subjects are also motivated by reciprocity:
they withdraw willingness to sacrifice to achieve a fair outcome when others are themselves unwilling to sacrifice, and sometimes
punish unfair behavior.
Much of the theory in personnel economics relates to effects of monetary incentives on output, but the theory was untested because appropriate data were unavailable. A new data set for the Safelite Glass Corporation tests the predictions that average productivity will rise, the firm will attract a more able workforce, and variance in output across individuals at the firm will rise when it shifts to piece rates. In Safelite, productivity effects amount to a 44-percent increase in output per worker. This firm apparently had selected a suboptimal compensation system, as profits also increased with the change.
We build a theory of prosocial behaviour that combines heterogeneity in individual altruism and greed with concerns for social reputation or self-respect. The presence of rewards or punishments creates doubt as to the true motive for which good deeds are performed, and this ‘overjustification effect’ can result in a net crowding out of prosocial behaviour by extrinsic incentives. The model also allows us to identify settings that are conducive to multiple social norms of behaviour, and those where disclosing one’s generosity may backfire. Finally, we analyse the equilibrium contracts offered by sponsors, including the level and confidentiality or publicity of incentives. Sponsor competition may cause rewards to bid down rather than up, and can even reduce social welfare by requiring agents to engage in inefficient sacrifices.
Much economic analysis -- and virtually all game theory -- starts with the assumption that people are both rational and selfish. The predictions derived from this assumption of rational selfishness are, however, violated in many familiar contexts. In this column and the next one, the evidence from laboratory experiments is examined to see what has been learned about when and why humans cooperate. This column considers the particularly important case of cooperation vs. free riding in the context of public good provision.