The Sting of Rejection: Deferring Blood Donors due to Low Hemoglobin Values Reduces Future Returns.

BACKGROUND: Roughly one quarter of short-term temporary deferrals (STTD) of blood donors are low-hemoglobin deferrals (LHD), i.e. STTD due to a hemoglobin (Hb) value falling below a cutoff of 125 g/L for female and 135 g/L for male donors. Since voluntarily donating blood is a prosocial activity, donors may perceive deferral as social exclusion, which can cause social pain, decrease self-esteem, and lead to antisocial behavior. However, little is known about the causal impacts of LHD on donor return. STUDY DESIGN AND METHODS: We conducted a quasi-experiment with 80,060 donors invited to blood drives in the canton of Zurich, Switzerland, between 2009 and 2014. Within a narrow window of Hb values around the predetermined cutoff, the rate of LHD jumps discontinuously. This discontinuous jump allows us to quantify the causal effects of LHD on donor return, as it is uncorrelated with other unobserved factors that may also affect donor return. RESULTS: We found different behavioral reactions to LHD for female and male donors. Female donors do not react to the first LHD. However, after any repeated LHD, they are 13.53 percentage points (p <0.001) less likely to make at least 1 donation attempt within the next 18 months and make 0.389 fewer donation attempts (p <0.001). Male donors react to the first LHD. They are 5.32 percentage points (p = 0.139) less likely to make at least 1 donation attempt over the next 18 months and make 0.227 (p = 0.018) fewer donation attempts. After any repeated LHD, male donors are 13.30 percentage points (p = 0.004) less likely to make at least 1 donation attempt and make 0.152 (p = 0.308) fewer donation attempts. CONCLUSION: LHD have detrimental impacts on donor return, especially if they occur repeatedly - suggesting that avoiding false LHD and helping donors to better cope with them helps to maintain the pool of prospective donors.

Numerical ability predicts mortgage default.

Unprecedented levels of US subprime mortgage defaults precipitated a severe global financial crisis in late 2008, plunging much of the industrialized world into a deep recession. However, the fundamental reasons for why US mortgages defaulted at such spectacular rates remain largely unknown. This paper presents empirical evidence showing that the ability to perform basic mathematical calculations is negatively associated with the propensity to default on one's mortgage. We measure several aspects of financial literacy and cognitive ability in a survey of subprime mortgage borrowers who took out loans in 2006 and 2007, and match them to objective, detailed administrative data on mortgage characteristics and payment histories. The relationship between numerical ability and mortgage default is robust to controlling for a broad set of sociodemographic variables, and is not driven by other aspects of cognitive ability. We find no support for the hypothesis that numerical ability impacts mortgage outcomes through the choice of the mortgage contract. Rather, our results suggest that individuals with limited numerical ability default on their mortgage due to behavior unrelated to the initial choice of their mortgage.

Call of duty: the effects of phone calls on blood donor motivation.

BACKGROUND: Little is known about the long-term effects of interventions aimed at increasing turnout among voluntary blood donors. STUDY DESIGN AND METHODS: We use a retrospective natural experiment with all 40,653 donors who were repeatedly invited to blood drives in Zurich, Switzerland, between 2010 and 2013. The intervention is a quasi-randomized phone call informing donors of a current shortage of their blood type. The panel structure of the data allows identification of different types of donors reacting to the phone call. RESULTS: Our analysis reveals two types. Type 1 donors make up 27.1% of the population. They are highly motivated and exhibit a baseline donation rate of 59.4% (p < 0.001). The phone call raises their probability to donate by 9.9% at the upcoming blood drive (p < 0.001). However, the phone call reduces their donation rate by 2.3% (p = 0.003) at each future blood drive. In contrast, the 72.9% of Type 2 donors exhibit a low baseline donation rate of 5.8% (p < 0.001). The phone call raises their probability to donate by 5.8% at the upcoming blood drive (p < 0.001). Moreover, the phone call leads to habit formation in Type 2 donors and increases their donation rate by 2.1% at the next blood drive (p = 0.03). CONCLUSION: Behavioral interventions are effective at increasing donation rates in the short run. However, they can crowd out the intrinsic motivation of the most motivated donors. Thus, blood donation services should avoid interventions for highly motivated donors and target them at irregular donors. Our results also sound a warning on using other interventions.

Cognitive skills affect economic preferences, strategic behavior, and job attachment.

Economic analysis has so far said little about how an individual's cognitive skills (CS) are related to the individual's economic preferences in different choice domains, such as risk taking or saving, and how preferences in different domains are related to each other. Using a sample of 1,000 trainee truckers we report three findings. First, there is a strong and significant relationship between an individual's CS and preferences. Individuals with better CS are more patient, in both short- and long-run. Better CS are also associated with a greater willingness to take calculated risks. Second, CS predict social awareness and choices in a sequential Prisoner's Dilemma game. Subjects with better CS more accurately forecast others' behavior and differentiate their behavior as a second mover more strongly depending on the first-mover's choice. Third, CS, and in particular, the ability to plan, strongly predict perseverance on the job in a setting with a substantial financial penalty for early exit. Consistent with CS being a common factor in all of these preferences and behaviors, we find a strong pattern of correlation among them. These results, taken together with the theoretical explanation we offer for the relationships we find, suggest that higher CS systematically affect preferences and choices in ways that favor economic success.

Prosociality predicts individual behavior and collective outcomes in the COVID-19 pandemic.

The COVID-19 pandemic induces a social dilemma: engaging in preventive health behaviors is costly for individuals but generates benefits that also accrue to society at large. The extent to which individuals internalize the social impact of their actions may depend on their prosociality, i.e. the willingness to behave in a way that mostly benefits other people. We conduct a nationally representative online survey in Germany (n = 5843) to investigate the role of prosociality in reducing the spread of COVID-19 during the second coronavirus wave. At the individual level, higher prosociality is strongly positively related to compliance with public health behaviors such as mask wearing and social distancing. A one standard deviation (SD) increase in prosociality is associated with a 0.3 SD increase in compliance (p < 0.01). At the regional (NUTS-2) level, a one SD higher average prosociality is associated with an 11% lower weekly incidence rate (p < 0.01), and a 2%p lower weekly growth rate (p < 0.01) of COVID-19 cases, controlling for a host of demographic and socio-economic factors. This association is driven by higher compliance with public health behaviors in regions with higher prosociality. Our correlational results thus support the common notion that voluntary behavioral change plays a vital role in fighting the pandemic and, more generally, that social preferences may determine collective action outcomes of a society.

Biased health perceptions and risky health behaviors-Theory and evidence.

This paper investigates the role of biased health perceptions as a potential driving force of risky health behaviors. We define absolute and relative health perception biases, illustrate their measurement in surveys and provide evidence on their relevance. Next, we decompose the theoretical effect into its extensive and intensive margin: When the extensive margin dominates, people (wrongly) believe they are healthy enough to "afford" unhealthy behavior. Finally, using three population surveys, we provide robust empirical evidence that respondents who overestimate their health are less likely to exercise and sleep enough, but more likely to eat unhealthily and drink alcohol daily.

Prosocial Motivation and Blood Donations: A Survey of the Empirical Literature.

Recent shortages in the supply of blood donations have renewed the interest in how blood donations can be increased temporarily. We survey the evidence on the role of financial and other incentives in eliciting blood donations among donors who are normally willing to donate pro bono. We present the predictions from different empirical/psychological-based theories, with some predicting that incentives are effective while others predict that incentives may undermine prosocial motivation. The evidence suggests that incentives work relatively well in settings in which donors are relatively anonymous, but evidence indicates also that when image concerns become important, incentives may be counterproductive as donors do not want to be seen as greedy.

Spillovers of prosocial motivation: Evidence from an intervention study on blood donors.

Blood donations are increasingly important for medical procedures, while meeting demand is challenging. This paper studies the role of spillovers arising from social interactions in the context of voluntary blood donations. We analyze a large-scale intervention among pairs of blood donors who live at the same street address. A quasi-random phone call provides the instrument for identifying the extent to which the propensity to donate spills over within these pairs. Spillovers transmit 41% to 46% of the behavioral impulse from one donor to the peer. This creates a significant social multiplier, ranging between 1.7 and 1.85. There is no evidence that these spillovers lead to intertemporal substitution. Taken together, our findings indicate that policy interventions have a substantially larger effect when targeted towards pairs instead of isolated individuals.

Free cholesterol testing as a motivation device in blood donations: evidence from field experiments.

BACKGROUND: Health tests are often seen as promising donor incentives to improve the supply of blood. However, systematic behavioral evidence on donor recruitment is scarce. STUDY DESIGN AND METHODS: To study the effectiveness of a free cholesterol test in attracting new donors and motivating previous donors, two field experiments were conducted. In Study 1, 2825 nondonors were randomly assigned to one of three treatments: a solicitation letter, a solicitation letter plus an appeal, or a solicitation letter plus an appeal and the offer of a free cholesterol test. In Study 2, 8269 previous donors were randomly assigned to one of three treatments: a standard invitation, an invitation plus an appeal, or an invitation plus an appeal and a cholesterol test. Marginal effects from probit estimations were calculated to study the effects of the treatments on donors' response. RESULTS: In Study 1, only 0.6 percent reacted to the solicitation letter. There were no significant differences in the response rates between the three treatments. In Study 2, 45.3 percent of the invited previous donors came to donate. The appeal (marginal effect, -0.5%; standard error [SE], 1.9%) and offering a cholesterol test (marginal effect, 1.6%; SE, 1.8%) did not significantly increase the probability of a donation relative to the standard invitation. The treatment effects for the cholesterol test did not systematically differ between frequent and infrequent donors and female and male donors. There is some evidence that young donors responded relatively most positive to the cholesterol test (marginal effect, 4.4%; SE, 2.2%). CONCLUSIONS: Contrary to conclusions from survey studies, free cholesterol testing did not significantly increase donations from nondonors and previous donors during a 3-month campaign. The two studies show that field experiments are an important method to evaluate donation incentives, because measuring donors' intentions alone can lead to significantly different conclusions.

Motivating household water conservation: A field experiment in Singapore.

We test and compare different incentives in motivating water conservation using a randomized controlled trial. In a field experiment carried out with Singaporean households, regular feedback was given, with informative, normative and monetary incentives provided to different groups. Evidence shows that all households saved an average of 4 Litres of water per person per day, with no difference in treatment effect found across various groups. Perhaps unsurprisingly, the water saving effect is also found to be more significant with high baseline users, who saved up to 5.9 Litres per person per day. High baseline households also respond more positively to the non-monetary incentives.

Do we harm others even if we don't need to?

Evolutionary explanations of the co-existence of large-scale cooperation and warfare in human societies rest on the hypothesis of parochial altruism, the view that in-group pro-sociality and out-group anti-sociality have co-evolved. We designed an experiment that allows subjects to freely choose between actions that are purely pro-social, purely anti-social, or a combination of the two. We present behavioral evidence on the existence of strong aggression-a pattern of non-strategic behaviors that are welfare-reducing for all individuals (i.e., victims and perpetrators). We also show how strong aggression serves to dynamically stabilize in-group pro-sociality.

Stress pulls us apart: anxiety leads to differences in competitive confidence under stress.

Social competition is a fundamental mechanism of evolution and plays a central role in structuring individual interactions and communities. Little is known about the factors that affect individuals' competitive success, particularly in humans. Key factors might include stress, a major evolutionary pressure that can affect the establishment of social hierarchies in animals, and individuals' trait anxiety, which largely determines susceptibility to stress and constitutes an important determinant of differences in competitive outcomes. Using an economic-choice experiment to assess competitive self-confidence in 229 human subjects we found that, whereas competitive self-confidence is unaffected by an individual's anxiety level in control conditions, exposure to the Trier social stress test for groups drives the behavior of individuals apart: low-anxiety individuals become overconfident, and high-anxiety individuals become underconfident. Cortisol responses to stress were found to relate to self-confidence, with the direction of the effects depending on trait anxiety. Our findings identify stress as a major regulator of individuals' competitiveness, affecting self-confidence in opposite directions in high and low anxious individuals. Therefore, our findings imply that stress may provide a new channel for generating social and economic inequality and, thus, not only be a consequence, but also a cause of inequality through its impact on competitive self-confidence and decision making in financially-relevant situations.