Psychological Sclence OnlineFirst,published on January 29.2014 as dol:10.1177/0956797613516148 Research Article Geographical Differences in Subjective Well-Being Predict Extraordinary Altruism 0.1177 567976155161 o SAGE Kristin M.Brethel-Haurwitz and Abigail A.Marsh Georgetown University Abstract ny donaonoory the anecedents of whicn are poony under e is known ence of pro nere is sigr it is u nt geograph variation in well-being predicts the prevalence of this form of extraordinary altruism.We calculated per nita rates of altruistic kidney donation across the United States and found that an index of subjective well-being predicted altruistic donation,even after we controlled for relevant sociodemographic variables. This relationship persisted at the state level and at the la relations promoted by societal factors that increase subjective well-being. ocial behvior.mpoa ondretedvn kidney donaion Received 7/31/13:Rev accepted 11/12/13 Altruistic kidney donation.or the donation of a kidney to well-being also shows strong regional variation and has a stranger,has been described as an act of "extraordinary been linked to common prosocial behaviors,such as vol unteering and charitable giving (Thoits Hewitt,2001) no Paymen except compensa exp vanation in wel tions in the United States since 1999 are maintained by vide a stranger with one of their 03: sey et a 2010 red by th sychological studies have been con ducted to assess the precursors of altruistic kidney the donor volunteers a kidney to an unknown recipient donation.nd most of these have employed retrospective Such a donation represents an intentional,costly behav S (B at benefiting an anony nonkin othe Norden 2008:Massev et al 2010)Th data ma Bat on.2010:Clavien Chapuisat.201 de Waal.2009) insufficient for capturing antecedents of altruism,which prone to self-report biases (Eisenberg 1983).Living kidney nding Author: donation in nied States in M 2013. ables.Subjective well-being may be one such variable: .mail:kb527georgetown.edu 11.201
Psychological Science 201X, Vol XX(X) 1–10 © The Author(s) 2014 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/0956797613516148 pss.sagepub.com Research Article Altruistic kidney donation, or the donation of a kidney to a stranger, has been described as an act of “extraordinary altruism” (Munson, 2002). Altruistic kidney donors receive no payment except compensation for medical bills, undergo exhaustive medical and psychiatric testing, may experience severe postsurgical pain, and are often treated with skepticism or even derision for their decision to provide a stranger with one of their own internal organs (Henderson et al., 2003; Massey et al., 2010). But little is known about the antecedents of this form of extraordinary altruism. Few psychological studies have been conducted to assess the precursors of altruistic kidney donation, and most of these have employed retrospective self-report data in small samples (Boulware et al., 2005; Henderson et al., 2003; Lennerling, Fehrman-Ekholm, & Norden, 2008; Massey et al., 2010). These data may be insufficient for capturing antecedents of altruism, which is notoriously prone to self-report biases (Eisenberg, 1983). Living kidney donation in the United States is unevenly distributed at the regional level (Matas et al., 2013), which suggests the importance of regional variables. Subjective well-being may be one such variable; well-being also shows strong regional variation and has been linked to common prosocial behaviors, such as volunteering and charitable giving (Thoits & Hewitt, 2001). We explored whether geographical variation in wellbeing predicts the prevalence of extraordinary altruism. Records on all nondirected (altruistic) kidney donations in the United States since 1999 are maintained by the Organ Procurement and Transplantation Network, which is administered by the United Network for Organ Sharing under contract with the U.S. Department of Health and Human Services. In a nondirected donation, the donor volunteers a kidney to an unknown recipient. Such a donation represents an intentional, costly behavior aimed at benefiting an anonymous, nonkin other, which satisfies the most stringent definitions of altruism (Batson, 2010; Clavien & Chapuisat, 2013; de Waal, 2009). 516148PSSXXX10.1177/0956797613516148Brethel-Haurwitz, MarshWell-Being and Altruism research-article2014 Corresponding Author: Kristin M. Brethel-Haurwitz, Department of Psychology, Georgetown University, White-Gravenor Hall, 3700 O St. N.W., Washington, DC 20057 E-mail: kb527@georgetown.edu Geographical Differences in Subjective Well-Being Predict Extraordinary Altruism Kristin M. Brethel-Haurwitz and Abigail A. Marsh Georgetown University Abstract Altruistic kidney donation is a form of extraordinary altruism, the antecedents of which are poorly understood. Although well-being is known to increase the incidence of prosocial behaviors and there is significant geographical variation in both well-being and altruistic kidney donation in the United States, it is unknown whether geographical variation in well-being predicts the prevalence of this form of extraordinary altruism. We calculated per capita rates of altruistic kidney donation across the United States and found that an index of subjective well-being predicted altruistic donation, even after we controlled for relevant sociodemographic variables. This relationship persisted at the state level and at the larger geographic regional level. Consistent with hypotheses about the relationship between objective and subjective well-being, results showed that subjective well-being mediated the relationship between increases in objective well-being metrics, such as income, and altruism. These results suggest that extraordinary altruism may be promoted by societal factors that increase subjective well-being. Keywords well-being, social behavior, altruism, prosocial nondirected living kidney donation Received 7/31/13; Revision accepted 11/12/13 Psychological Science OnlineFirst, published on January 29, 2014 as doi:10.1177/0956797613516148 Downloaded from pss.sagepub.com by Cai Xing on February 11, 2014
Bretbel-Haurwitz,Marsb Altruistic kidney donations cannot be readily explained others,supporting democracy:Aknin.Dunn.Norton by other dominant self-serving explanations for altruistic 2011;Diener Ryan,2009;Krueger,Hicks,McGue behavior,in luding kir selection, 00I cial behaviors also meet The of these donaio ey e nd thei normative nature have raised many questions about their Bove,2011;Bekkers Wiepking,2011).It remains unclear causes (Henderson et al.,2003). whether subjective well-being can also promote acts of evidence y altruism.This is sed quality of life (Kahneman.Diener. kidney donation is that such donations are exceedingly Schwarz,2003).Objective well-being,which reflects rare;per capita rates of altruistic kidney donation are les than 1 in 10,000.This base rate renders indivi can wa This ob sures that capture,in aggregate,associations Wascher,2003;Oswald Wu,2010).Subjective well- at the individual level (iener Tay.Oishi 2013)A elf rd engagement meaning.and numose and ng D tions and life satisfaction (Diener.2012:Ryan Deci .well-beingindex.com/).Gallup-Healthways hasc nducte 2001).A recently proposed"engine"model of well-being nationwide sampling of well-being since 2008.thereby incorporates these of well-being and creating the m s extensive ollection of well-being ing rep bat. nt inpu the co he index taps into more &C lead to voluntary.beneficent well-being outcomes and 2000 and includes both ex perienced and evaluative well activities (Jayawickreme,Forgeard,&Seligman 2012) being (i.e,self-reported well-being in the moment and Well-being outcomes are retrospectively),which is a recomme pursu thei .CO bute to geneind e06 hneman Riis Our aim in this study was to evaluate the relationshin changes in objective well-being would be anticipated to between this nationally representative index of well well-being.which would lead to being and per capita kidney in s to prom extrao for well-being outcomes.Donors con istently h desire to help another person as their primary motivation median income,age,and physical health,which may be for donating (Henderson et al. 2003: Lennerling associated with both well-being and altruistic donation sberg,Meyer, 201d are not hypothesized to drive the association between the two out exception,donors self-report that donation positively Method affected their psychological well-being and that the 2010 decision to donat again (Mass vant to our hypothe e in on P cally ne tha statistics provided by the United Network for Organ kidney donations between 1999 and 2010 (Organ Sharing (Matas et al., 2013).Together,these factors sup- Procurement and Transplantation Network,2011)and port the hypothesis that increases in well-being may pro ents well-being (Gallup 20 well-b less extreme prosocial behaviors at the individual wide demographic and economic information indices o level (spending money on others,volunteering)and at physical and mental health,and state characteristics of the community level (trusting others,cooperating with collectivism and religiosity
2 Brethel-Haurwitz, Marsh Altruistic kidney donations cannot be readily explained by other dominant self-serving explanations for altruistic behavior, including kin selection, reciprocity, or adherence to social norms (Batson, 2010; Massey et al., 2010). The rarity of these donations and their strongly counternormative nature have raised many questions about their causes (Henderson et al., 2003). Converging strands of evidence have suggested that well-being may promote altruistic kidney donation. Wellbeing is a broad construct that comprises objectively and subjectively assessed quality of life (Kahneman, Diener, & Schwarz, 2003). Objective well-being, which reflects objectively measured basic human needs (e.g., economic resources, access to clean water, and good health), affords individuals the opportunity to engage in activities that contribute to subjective well-being (Gabriel, Mattey, & Wascher, 2003; Oswald & Wu, 2010). Subjective wellbeing incorporates both eudemonic components, such as self-reported engagement, meaning, and purpose, and hedonic components, such as self-reported positive emotions and life satisfaction (Diener, 2012; Ryan & Deci, 2001). A recently proposed “engine” model of well-being incorporates these various elements of well-being and posits that objective indices of well-being represent input variables that promote subjective processes that, in turn, lead to voluntary, beneficent well-being outcomes and activities (Jayawickreme, Forgeard, & Seligman, 2012). Well-being outcomes are defined as outcomes that are pursued for their own sake, contribute to general wellbeing, and are characterized and measured independently of other outcomes. Under this model, positive changes in objective well-being would be anticipated to increase subjective well-being, which would lead to increases in well-being outcomes. Altruistic kidney donation satisfies these three criteria for well-being outcomes. Donors consistently report the desire to help another person as their primary motivation for donating (Henderson et al., 2003; Lennerling, Forsberg, Meyer, & Nyberg, 2004; Massey et al., 2010). They also report high levels of well-being after donation (Lennerling et al., 2008; Massey et al., 2010); nearly without exception, donors self-report that donation positively affected their psychological well-being and that they would make the same decision to donate again (Massey et al., 2010). Finally, altruistic kidney donation is a concrete outcome that can be independently measured using statistics provided by the United Network for Organ Sharing (Matas et al., 2013). Together, these factors support the hypothesis that increases in well-being may promote altruistic donation. Researchers have linked subjective well-being to less extreme prosocial behaviors at the individual level (spending money on others, volunteering) and at the community level (trusting others, cooperating with others, supporting democracy; Aknin, Dunn, & Norton, 2011; Diener & Ryan, 2009; Krueger, Hicks, & McGue, 2001). However, these prosocial behaviors also meet a range of self-serving goals, such as adherence to perceived social norms and enhancement of reputation (Bednall & Bove, 2011; Bekkers & Wiepking, 2011). It remains unclear whether subjective well-being can also promote acts of unambiguous and lifesaving extraordinary altruism. This is what we sought to determine in our study. One difficulty in identifying antecedents of altruistic kidney donation is that such donations are exceedingly rare; per capita rates of altruistic kidney donation are less than 1 in 10,000. This very low base rate renders individual-level assessments infeasible for capturing predictors of donation. This obstacle can be superseded by comparing regional measures that capture, in aggregate, associations at the individual level (Diener, Tay, & Oishi, 2013). A nationally representative regional assessment of subjective well-being in the United States recently became available: the Gallup-Healthways Well-Being Index (http://www .well-beingindex.com/). Gallup-Healthways has conducted nationwide sampling of well-being since 2008, thereby creating the most extensive collection of well-being data in the country. The index taps into more dimensions of wellbeing than does most past research (Diener & Seligman, 2004) and includes both experienced and evaluative wellbeing (i.e., self-reported well-being in the moment and retrospectively), which is a recommended approach, given the biases that affect each perspective (Kahneman & Riis, 2005). Our aim in this study was to evaluate the relationship between this nationally representative index of wellbeing and per capita altruistic kidney donations across states to establish whether well-being promotes extraordinary altruism. We assessed the relationship between these variables while controlling for covariates, including median income, age, and physical health, which may be associated with both well-being and altruistic donation but which are not hypothesized to drive the association between the two. Method We obtained data relevant to our hypotheses using publically available databases and previously published research. Variables included statistics on nondirected kidney donations between 1999 and 2010 (Organ Procurement and Transplantation Network, 2011) and statewide assessments of well-being (Gallup, 2012). We also accounted for variables that may be confounded with our primary variables of interest, including statewide demographic and economic information, indices of physical and mental health, and state characteristics of collectivism and religiosity. Downloaded from pss.sagepub.com by Cai Xing on February 11, 2014
Well-Being and Altruism Altruistic donations by state Indices of well-being by state Sharing and were ba The Gallup-Heaing Index.a component of up,2012 (2011 data as of lune 19.2011.These data included the States that comprises six components.The life state of residence for all nondirected kidney donors from component is based on the Cantril Ladder Scale (Cantril which ded ere av action 5 years in experience of smiling and laughter.worry.and othe emotional variables.Physical bealtb includes feeling well-rested and reported sick days. and ea thful The t ondenr's relationshin with his or her sunervisor lated for each state using the 2010 census data for the access indudes feeling safe and having enough money for population 18 and older as the population base The basic needs.Gallup-Healthways surveys a minimum inimun living kidn 1,000 adult es each day via botl ombined to only.)Thus,overall per capita donation rates repr sent each state's total number of donors from 1999 to 2010 Covariates by state by that s for stare in 2010 divided b Both well-being and altruistic donation may covary with total per capita don alth sta 0)an ach state's media Table 1.D ents. e of White,non-Hispanic res Demographic variable donors se Bureau 2000)and 2010 (US Census Bureau 2012)cen 535 56.0m sus data.We collected statistics on educational attainmen 420 43.98 000 through urea Age (years) h lated for the proportion of the population aged 18 and 35-4 25.3 older.Educa l-attainment statistics were for adults 32 age d 25 and olde an hor 65+ 251 hold inc ne (s Census Bur eau 201b)and Gini coef Race/ethnicity ficient,a measure of income inequality (Noss,2011;U.S Census Bureau, 2005) Because Black nic altruistic donors must ealt 30 physical-h 3.1 pass mental-and Asian de d/n ve 436 t0 days mental health through the Behavioral Risk Factor Surveillance System,a nationwide health survey con Control and Prevention 11,201
Well-Being and Altruism 3 Altruistic donations by state Statistics on altruistic kidney donation were provided by the United Network for Organ Sharing and were based on Organ Procurement and Transplantation Network (2011) data as of June 19, 2011. These data included the state of residence for all nondirected kidney donors from January 1999 to June 2011. Between 1999 and 2010, the most recent year for which complete data were available, 955 altruistic donations were recorded. Donors’ demographic information is presented in Table 1. All 955 donors’ states of origin were included in further analyses except for Washington, D.C., and Puerto Rico, for which scores on the Gallup-Healthways Well-Being Index and other key variables were unavailable. Per capita donations for the period from 1999 to 2010 were also calculated for each state using the 2010 census data for the population 18 and older as the population base. (The minimum age for eligibility for altruistic living kidney donation is 18; in addition, the Gallup-Healthways WellBeing Index includes responses of adults 18 and older only.) Thus, overall per capita donation rates represent each state’s total number of donors from 1999 to 2010 divided by that state’s 2010 adult population. Per capita donation rates for 2010 represent the total number of donors for a state in 2010 divided by the state’s adult population in 2010. We identified state-level correlates of total per capita donations by state as well as per capita donations for 2010 only. Indices of well-being by state The Gallup-Healthways Well-Being Index, a component of Gallup Daily Tracking (Gallup, 2012), is a state-level measure of self-reported subjective well-being in the United States that comprises six components. The life-satisfaction component is based on the Cantril Ladder Scale (Cantril, 1965) and evaluates life satisfaction at the current moment of the survey and expected life satisfaction 5 years in the future. Emotional health includes the respondent’s daily experience of smiling and laughter, worry, and other emotional variables. Physical health includes feeling well-rested and reported sick days. Healthy behavior includes exercise and eating a healthful diet. The workenvironment component includes job satisfaction and the respondent’s relationship with his or her supervisor. Basic access includes feeling safe and having enough money for basic needs. Gallup-Healthways surveys a minimum of 1,000 adults across the United States each day via both landlines and cell-phone lines; results of these surveys are then combined to create an annual index. Covariates by state Both well-being and altruistic donation may covary with sociodemographic variables that are not predicted to drive the well-being/altruism relationship, including age, sex, race, education, health status, and income (Boulware et al., 2005; Diener & Ryan, 2009). Our regression analyses therefore included as covariates each state’s median age, male-to-female sex ratio, proportion of the population with a high school degree or higher, and proportion of White, non-Hispanic residents. Data on race, sex, and median age were obtained from the U.S. Census Bureau; we used intercensal estimates from 1999 (U.S. Census Bureau, 2000) and 2010 (U.S. Census Bureau, 2012) census data. We collected statistics on educational attainment for 2000 through the U.S. Census Bureau (2006) and for 2010 through the U.S. Census Bureau (2011a) via the American Community Survey. Race and sex were calculated for the proportion of the population aged 18 and older. Educational-attainment statistics were for adults aged 25 and older. Economic variables included state-level median household income (U.S. Census Bureau, 2011b) and Gini coefficient, a measure of income inequality (Noss, 2011; U.S. Census Bureau, 2005). Because altruistic donors must also pass mental- and physical-health screenings, we included state averages for the number of days within the past 30 days that respondents reported poor physical or mental health through the Behavioral Risk Factor Surveillance System, a nationwide health survey conducted by the Centers for Disease Control and Prevention (United Health Foundation, 2013). Table 1. Demographics of Altruistic Living Kidney Donors in the United States (1999–2010) Demographic variable n Percentage of donors Sex Female 535 56.02 Male 420 43.98 Age (years) 18–24 50 5.24 25–34 169 17.70 35–44 242 25.34 45–54 312 32.67 55–64 158 16.54 65+ 24 2.51 Race/ethnicity White 878 91.94 Hispanic 24 2.51 Black 30 3.14 Asian 14 1.47 American Indian/Alaskan Native 3 0.31 Multiracial 6 0.63 Note: Data were drawn from the Organ Procurement and Transplantation Network (2011). Downloaded from pss.sagepub.com by Cai Xing on February 11, 2014
Bretbel-Haurwitz,Marsb State-level indices of collectivism-individualism and Bureau.7)=.83(p=.005),p7)=83(p=.005).Thes religiosity were also examined because of suggested results support the existence of a strong positive relation- links between thes variable and prosocial be ship between regional-leve well-being and the preva ntrol for the p survey of individuals conducted from 1993 to 1996,in collected we also c which states were ranked according to respondents' donation data from 2010 only.Although this variable i ieiocRtcftndnitaliandcolectinibehaios inherently more unstable because it relies on a smalle 2011G99 001 Gallup Daily Tracking (Gallup,2012).in which respon- These correlations were again replicated for the nine dents were asked the extent to which religion was an broader geographic regions,()=.83 (p=.006),p(7)= 85 5).which reaffirmed the stro ach sta s.On hip bet biased the observed association between well-being fied as "very religious and altruism,we next estimated a regression model pre altruistic-donation rates from Analysis strategy th Several strategies were used to examine the association following covariates:median houschold income.Gin between altruistic kidney donation and well-being at the coefficient,percentage of non-Hispanic Whites,sex ratio state level.In addition to investigating biva ducational tions phys we acco identify r otential contributions of sociodemogranhi altruism.B=0.58.(40)=236.p=023 (see Table 2 for economic,health,and social influences,including state results).Well-being also remained a significant predictor 0 capita donation rates when 2011 religiosity was the primary units of ana we als d as a cov te, 59,39 .50,P -023 raphic regions of the United States as defined set of covariates collected by the U.s.census Bureau). in1and 20.well-bein again predicted altruism,B=0.48,(40)=2.25.p=.030 (see Table 3 for results). In this well-being Results rem r o sm whe 10. State-level rates of altruistic kidne donation ae.B=04239=216. 037 Tog these findings suggest that the relatic nship between well from0to 76,which translates to per capita lonation rates being and altruism is not a function of basic sociodemo 0.000029(LUa graphic regional variation in religiosity Well-Being Indes d from 61.7(West virginia)to redicts that im (Hawaii;see Fig.1). ments in objective well-being result in subjective changes We first examined the bivariate association between hat promote well-being outcomes, such as altru 2010 state-leve -be 0 nog and er capita donation rate 3,201 gges s tha ective w (48)=52.001 (see Fig.2).To account for possible exa mined how positive changes in obiective measures o high-leverage outliers (in particular,Utah's donation rate well-being,which are known to promote subjective well- was 4.55 SD above the so conducted a ra eing (Di et al. donations <.001.1hs7S ve c 100 201 After controlling for baseline (1999)median income broader geographic regions defined by the U.S.Census we found that increases in median income from 1999 to
4 Brethel-Haurwitz, Marsh State-level indices of collectivism-individualism and religiosity were also examined because of suggested links between these variables and prosocial behavior (Henderson et al., 2003; Vandello & Cohen, 1999). The collectivism-individualism index was based on a national survey of individuals conducted from 1993 to 1996, in which states were ranked according to respondents’ endorsement of individualist and collectivist behaviors (Vandello & Cohen, 1999). The religiosity index was based on a 2011 Gallup survey, also a component of Gallup Daily Tracking (Gallup, 2012), in which respondents were asked the extent to which religion was an important aspect of their lives and the frequency with which they attended religious services. On the basis of responses to these questions, each state’s religiosity score was calculated as the percentage of respondents classified as “very religious.” Analysis strategy Several strategies were used to examine the association between altruistic kidney donation and well-being at the state level. In addition to investigating bivariate correlations between altruistic donations and well-being, we used multiple linear regression and mediation analyses to identify potential contributions of sociodemographic, economic, health, and social influences, including statelevel measures of collectivism and religiosity. The 50 states constituted the primary units of analysis. We also investigated associations at the regional level (i.e., the nine geographic regions of the United States as defined by the U.S. Census Bureau). Results State-level rates of altruistic kidney donation vary widely. Between 1999 and 2010, total donors per state ranged from 0 to 76, which translates to per capita donation rates ranging from 0 (Delaware, Mississippi) to 0.000029 (Utah; see Fig. 1). Scores from the 2010 Gallup-Healthways Well-Being Index ranged from 61.7 (West Virginia) to 71 (Hawaii; see Fig. 1). We first examined the bivariate association between 2010 state-level well-being and per capita donation rates from 1999 to 2010 and found a positive association between well-being and per capita altruistic donation, r(48) = .52, p < .001 (see Fig. 2). To account for possible high-leverage outliers (in particular, Utah’s donation rate was 4.55 SD above the mean), we also conducted a rankorder correlation, which yielded comparable results, ρ(48) = .70, p < .001. This pattern was also replicated when state-level data were collapsed into the nine broader geographic regions defined by the U.S. Census Bureau, r(7) = .83 (p = .005), ρ(7) = .83 (p = .005). These results support the existence of a strong positive relationship between regional-level well-being and the prevalence of extraordinary altruism. To control for the period during which the data were collected, we also conducted analyses using altruisticdonation data from 2010 only. Although this variable is inherently more unstable because it relies on a smaller sample, the pattern of observed results remained very similar, r(48) = .42 (p = .003), ρ(48) = .45 (p = .001). These correlations were again replicated for the nine broader geographic regions, r(7) = .83 (p = .006), ρ(7) = .83 (p = .005), which reaffirmed the strong positive relationship between regional well-being and altruism. To control for confounding variables that may have biased the observed association between well-being and altruism, we next estimated a regression model predicting per capita altruistic-donation rates from 1999 to 2010 from subjective well-being, as measured by Gallup-Healthways, with the additional inclusion of the following covariates: median household income, Gini coefficient, percentage of non-Hispanic Whites, sex ratio, median age, educational attainment, and indices of poor mental and physical health. Even after we accounted for covariates, well-being remained a significant predictor of altruism, β = 0.58, t(40) = 2.36, p = .023 (see Table 2 for results).1 Well-being also remained a significant predictor of per capita donation rates when 2011 religiosity was added as a covariate, β = 0.59, t(39) = 2.36, p = .023. When we performed this regression using the same set of covariates collected in 1999 and 2000, well-being again predicted altruism, β = 0.48, t(40) = 2.25, p = .030 (see Table 3 for results). In this model, well-being remained a significant predictor of altruism when collectivism (collected between 1993 and 1996) was added as a covariate, β = 0.42, t(39) = 2.16, p = .037. Together, these findings suggest that the relationship between wellbeing and altruism is not a function of basic sociodemographic factors, including regional variation in religiosity or collectivism-individualism. The engine model of well-being predicts that improvements in objective well-being result in subjective changes that promote well-being outcomes, such as altruism (Jayawickreme et al., 2012). This model suggests that subjective well-being mediates the relationship between objective well-being and altruism. To test this model, we examined how positive changes in objective measures of well-being, which are known to promote subjective wellbeing (Diener et al., 2013), influence altruistic donations. We considered positive changes in both median income and health status across states from 1999 to 2010. After controlling for baseline (1999) median income, we found that increases in median income from 1999 to Downloaded from pss.sagepub.com by Cai Xing on February 11, 2014
Well-Being and Altruism Per Capita Donation Rates Well-Being Scores (3 time p separate regressions with and without the inclusion of the test showed that subjective well-being mediated the 11,201
Well-Being and Altruism 5 2010 predicted rates of altruistic donations during that time period, β = 0.33, t(47) = 2.61, p = .012. We estimated separate regressions with and without the inclusion of our hypothesized mediator (well-being) and conducted a Sobel test; consistent with the engine model, results of the test showed that subjective well-being mediated the Quintiles 1 2 3 4 5 Per Capita Donation Rates Quintiles 1 2 3 4 5 Well-Being Scores Fig. 1. Per capita altruistic living kidney donation rates (1999–2010) and 2010 Gallup-Healthways Well-Being Index scores across states. Data on kidney-donation rates were drawn from the Organ Procurement and Transplantation Network (2011); Well-Being Index scores were drawn from Gallup (2012). Quintile 1 represents the highest well-being/altruistic donation rates. Downloaded from pss.sagepub.com by Cai Xing on February 11, 2014