Psychology week 7 assignment 2
bmarlurer8
McCulloughprosocial2.pdf
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1 Part 3 Core Topics in Social Psychology
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1 Chapter 8
Prosocial Behavior Michael E. McCullough and Benjamin A. Tabak
Chimpanzees are our closest living relatives, with % of our genetic code over- lapping theirs (Varki & Nelson, ). Th is deep genetic similarity produces profound physical similarities—and also behavioral ones. Th ese behavioral similarities are nowhere better illustrated than in the realm of prosocial behav- ior. Chimpanzees, like humans from hunter–gatherer societies, hunt coopera- tively. Like humans, they patrol their territories in groups and engage in coordinated group violence against other groups (Wrangham & Peterson, ). Within groups, they form coalitions to defeat individuals too powerful for any of the coalition members to defeat on their own (de Waal, ), and males join forces to prevent each others’ mates from straying (Silk et al., ). Individuals also make an eff ort to reconcile with valuable relationship partners with whom they have recently experienced confl ict (Koski, Koops, & Sterck, ) and to comfort valuable relationship partners who have recently been the recipients of other individuals’ aggressive behavior (Fraser, Stahl, & Aureli, ). In addition, chimpanzees recognize when they need a partner to obtain a desirable food item, and they know which potential partners are likely to be most helpful to them (Melis, Hare, & Tomasello, ). Evidence also suggests that chimpanzees, like humans, will help others gain access to desired items even when they cannot immediately benefi t from a return favor (Warneken, Hare, Melis, Hanus, & Tomasello, ; Warneken & Tomasello, ).
But we cannot overlook that % uniqueness, which indicates that there are approximately million genetic diff erences between humans and chimpanzees
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1 due to base pair diff erences and nucleotide additions or deletions (Varki & Nelson, ). Th at uniqueness leads to important diff erences in human and chimpanzee prosocial behavior. For example, chimpanzees show no preference for behaviors that enable others to acquire food when they are attempting to acquire food (Jensen, Hare, Call, & Tomasello, ; Silk et al., ), but such behavior is common among humans to the point of banality: If I’m going out to get lunch, I just might off er to pick something up for you. Moreover, human infants are better than chimpanzees at inferring humans’ needs and then ren- dering appropriate forms of help (Warneken & Tomasello, ). Likewise, even though both humans and chimpanzees help others in some instances, it is humans and not chimpanzees that raise armies for the common defense, seek out training so that they can render more eff ective emergency aid to others, and endure taxation to provide help for the poor and needy. Th ese important behav- ioral diff erences may refl ect fundamental qualitative diff erences in evolved cog- nitive capacities such as delay of gratifi cation (Stevens, Cushman, & Hauser, ), the ability to infer other people’s mental states from their behavior and to act empathically on the basis of that knowledge (Liszkowski, Carpenter, & Tomasello, ), and the ability to generate and learn from culture (Richerson & Boyd, ). In this chapter, we will explore some of the more interesting features of humans’ tendencies to engage in helping, sharing, and cooperating— that is, the behaviors collectively known as “prosocial behaviors” (Penner, Dovidio, Piliavin, & Schroeder, ). We will describe the classic social– psychological work on this topic, and also some of the more important recent theoretical and empirical advances, beginning with the evolutionary models that are sometimes invoked to explain humans’ prosocial tendencies.
Evolutionary Models of Prosocial Behavior
Evolutionary researchers study the body’s (brain/mind included) present struc- tures by searching for the functions those structures evolved to serve in the past: Th eir project is usually (although not always; Andrews, Gangestad, & Matthews, ) an adaptationist one (Tooby & Cosmides, ; see Maner & Kenrick, Chapter , this volume). Adaptationism relies on the fact that indi- vidual organisms within a population that vary on a trait due to genotypic diversity can incur diff ering rates of genetic propagation (i.e., fi tness) if some variants of the trait (and, therefore, the genes that contribute to their assembly during development) cause higher rates of reproduction than do others because of their ability to cause organisms to respond to specifi c adaptive challenges eff ectively. Because of these phenotype-dependent diff erences in fi tness, small
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1 incremental changes in the genes that collectively give rise to the body’s mecha- nisms (e.g., the heart, the fi ngernails, the brain’s reward circuitry) that enhance the fi tness of the bearer of those genes can gradually shape the species-typical structure of those mechanisms.
Because of natural selection’s relentless favoritism for genes that enhance their bearers’ fi tness, prosocial behavior has been an evolutionary puzzle since Darwin (/): Incurring costs (even small costs in the currencies of money, time, or energy should redound to fi tness) that benefi t someone else’s fi t- ness (e.g., when someone saves a drowning child or donates blood for a stranger’s benefi t) at fi rst glance appears to be bad evolutionary bookkeeping. Nevertheless, several evolutionary processes have been identifi ed that can help explain the evo- lution of mental mechanisms for prosocial behavior in humans (McAndrew, ; Nowak, ; Wilson & Wilson, ). Here, we focus on the models that have (we think) the greatest potential to inform social psychology: kin altruism, direct reciprocity, indirect reciprocity, signaling, and group (or multilevel) selec- tion. What makes these theories useful to social psychology is that they imply that the mind possesses specifi c functional systems that natural selection designed for their effi cacy in producing certain types of prosocial behavior. If we under- stand the selection pressureswe can formulate hypotheses about the operation of the psychological systems that evolved in response to those pressures and the social factors that activate and condition the operation of those systems.
Kin Altruism
Humans regularly endure tremendous energetic costs (e.g., gestation, nursing, feeding, sheltering, clothing, paying for college) to help their off spring and other genetic relatives. Th e theory of kin altruism explains such behaviors by exploit- ing the fact that one’s fi tness is not a function of the number of one’s off spring that survive to reproductive maturity, but rather a function of the number of off spring one has plus the number of off spring that one’sour genetic relatives have (Hamilton, ). Th e theory of kin altruism specifi es that certain forms of prosocial behavior that are benefi cial to the recipient and costly to the helper can evolve when the benefi t B to the individual being helped is greater than the cost C to the helper, discounted by a coeffi cient of relatedness r between the helper and the individual being helped (with r = . being the degree of relatedness between identical twins, r = . between fi rst-degree relatives, r = . between grandparents and their grandchildren, or uncles and aunts and their nieces and nephews, and so on; Hamilton, ), which is equivalent to the likelihood that the recipient also possesses the helper’s “altruism gene.” In other words, specifi c forms of kin altruism are evolutionarily plausible when C < rB.
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1 In support of Hamilton’s () model, people report more willingness to provide help (particularly biologically costly help) to closely related genetic relatives than to more distant ones (Bressan, ; Burnstein, Crandall, & Kitayama, ; Korchmaros & Kenny, ; Lieberman, Tooby, & Cosmides, ; Stewart-Williams, ). Estimates of migrant workers’ remittances to their families back at home based on two factors—() the fi tness costs the worker incurs by sending money back home and () the fi tness benefi ts the worker receives via the enhanced fi tness of the relatives who benefi t from the remittance—account for roughly one-third of the variance in the amounts that those workers actually send home (Bowles & Posel, ).
If humans’ penchant for prosocial behavior really did evolve in part via kin altruism, then the selection pressure for kin altruism should have left its imprint on the mind’s cognitive architecture: If ancestral humans had been unable to reli- ably identify their genetic relatives, then their prosocial behavior could not have produced benefi cial fi tness consequences for them via Hamilton’s () rule. Lieberman, Tooby, and Cosmides () outlined the workings of a hypothesized “kinship estimator” that computes the degree of relatedness between a potential benefi ciary and the benefactor. Among siblings, the kinship estimator appears to use two ancestrally reliable cues: () the degree of “maternal perinatal association” (i.e., the amount of time that the individual was in a long-term perinatal relation- ship with his or her own mother) and () the degree of sibling coresidence (i.e., the amount of time that the two individuals lived together during childhood). When these cues imply a high degree of relatedness, the benefactor is more likely to help a person in need (Lieberman et al., ). Th e challenge of identifying one’s kin seems trivial here only because we are thinking about humans—a species about which we all feel like experts rather than, say, lemurs (Charpentier, Boulet, & Drea, ), a species about which most of us know almost nothing.
Th e mind should also be sensitive to cues about the remaining reproductive potential of one’s kin because it is partly through a relative’s future reproductive potential that it is self-serving for people to provide costly help to their kin (Bowles & Posel, ). In support of this proposition, Burnstein et al. () found that participants reported more willingness to provide costly help (e.g., saving someone from a fi re) to relatives who were healthy (i.e., with greater potential for future reproduction) than to relatives who were not healthy (and whose future reproductive potential was therefore more limited).
Direct Reciprocity
Th e theory of direct reciprocity posits that mechanisms for prosocial behavior can evolve when the likelihood is greater than zero that the recipient of help
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1 will be disposed to help the benefactor in the future if the need arises (Nowak, ). Trivers () fi rst coined the term reciprocal altruism to describe this form of interaction, and demonstrated mathematically that under some condi- tions, behavioral systems for reciprocal altruism could evolve in social species.
A widely used paradigm for research on reciprocal altruism is the prisoner’s dilemma (Rapoport & Chammah, ), in which two participants are presented with a choice either to cooperate with, or to defect against, their partner. If both partners cooperate, they receive a moderate reward (the so-called “reward for mutual cooperation”). If both partners defect, both earn a small payoff called the “punishment for mutual defection.” If one individual defects and the other coop- erates, the defector receives a large boon called the “temptation to defect” and the cooperator receives the smallest payoff —the “sucker’s payoff .”
Unconditional defection is the rational course of action in the prisoner’s dilemma because it provides the best outcome both when one’s partner defects and when one’s partner cooperates. However, the prisoner’s dilemma becomes more interesting when the two individuals play multiple rounds of the game rather than only one round, allowing them to make choices based on their part- ners’ behavior in previous rounds. In a landmark study in which players from around the world submitted computer programs that would execute strategies for playing this so-called iterated prisoner’s dilemma, Axelrod () sought to determine which strategies would score the most points against all of the other strategies that were submitted.
A simple strategy called “tit-for-tat” emerged victorious. Tit-for-tat begins an iterated game with a cooperative move. If the partner also cooperates, then tit-for-tat continues to cooperate. If the partner defects on a given round, how- ever, tit-for-tat will defect on the successive round. If the defecting player ever returns to cooperating, then tit-for-tat will also return to cooperating on the next round. Tit-for-tat has several characteristics that make it eff ective in iterated games: it is () “nice” (i.e., it begins by cooperating), () retaliatory (it responds to defection with defection), () forgiving (i.e., when a defecting part- ner returns to cooperation, it returns to cooperation as well, and () clear (i.e., its decisions are honest and easy to understand). It does well in iterated games with a wide variety of strategies not by dominating them, but by racking up rela- tively high tie scores in games with other opponents that are disposed to cooper- ate and by preventing more selfi sh strategies from getting the best of itself.
Axelrod and Hamilton () demonstrated that the iterated prisoner’s dilemma provides a game-theoretic model for the evolution of Trivers’s () reciprocal altruism. Nowak () showed formally that direct reciprocity (as modeled in the prisoner’s dilemma) can favor the evolution of cooperation in social species when the probability of a successive round of interaction between two interactants exceeds the ratio of the costs of the altruistic act to the
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1 benefactor divided by the value of the benefi t to the recipient. Th e fact that much, if not most, of human social life (especially the social life of small groups of hunter–gatherers and, by extension, our ancestors) involves iterated games rather than single one-shot games may explain why people in (as far as we know) every society studied to date tend to be more generous and prosocial in economic games such as the prisoner’s dilemma than standard economic theo- ries for the one-shot prisoner’s dilemma predict (Henrich et al., ; Hoff man, McCabe, & Smith, ; Simpson & Beckes, ).
Just as evolutionary psychologists interested in social behavior have deduced that the mind possesses specialized cognitive systems for computing kinship (Lieberman, Tooby, & Cosmides, ), they also have deduced that the mind possesses specialized cognitive machinery for detecting individuals who might cheat in the types of social contracts (i.e., “If you’ll help me now, I’ll help you later”) that the prisoner’s dilemma attempts to model (Cosmides, ; Cosmides & Tooby, ). Using a variant of the Wason Selection task (which illustrates that people are not very good at marshaling the right kinds of evidence to test the validity of logical statements of the form if P, then Q), Cosmides and Tooby () showed that people are more accurate at testing evidence to deter- mine whether particular individuals have cheated on a social contract. People’s relatively good skill at detecting cheaters is as true of American undergraduates as it is of people from the Shiwiar, a remote society of hunter/horticulturalists in Amazonian Ecuador (Sugiyama, Tooby, & Cosmides, ).
Others researchers have proposed that gratitude might be part of the evolved psychological system that governs reciprocal altruism (McCullough, Kilpatrick, Emmons, & Larson, ; McCullough, Kimeldorf, & Cohen, ; Trivers, ). Gratitude is a reliable emotional response to receiving help from another person that was valuable to the self, costly to the donor, and intention- ally rendered (Tesser, Gatewood, & Driver, ; Tsang, ). Th e experience of gratitude leads to reciprocation (Bartlett & DeSteno, ; Tsang, ) and strengthens relationships between benefactors and benefi ciaries (Algoe, Haidt, & Gable, ).
Forgiveness might also be an important component of the evolved psycho- logical apparatus that facilitates reciprocal altruism, and perhaps also kin altru- ism as well (McCullough, ; McCullough, Kurzban, & Tabak, ). In the context of reciprocal altruism in particular, responding to defections by occasion- ally forgiving them rather than retaliating can help to preserve cooperation when there is a possibility that individuals might make mistakes in implementing their prosocial intentions, or might mistake their partners’ prosocial intentions for selfi sh ones (Van Lange, Ouwerkerk, & Tazelaar, ). People who forgive their relationship partners for interpersonal transgressions experience greater restora- tions of positive relations (Karremans & Van Lange, ; Tsang, McCullough, &
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1 Fincham, ) and elicit prosocial behavior from partners who have trans- gressed (Kelln & Ellard, ; Wallace, Exline, & Baumeister, ). In support of the contention that the capacity to forgive was naturally selected on the basis of selection pressure for the maintenance of valuable relationships, people are more forgiving of relationships in which the transgressor and victim are close and com- mitted (Finkel, Rusbult, Kumashiro, & Hannon, ; McCullough et al., ) and in which transgressors have communicated (e.g., through apologies or other expressions of remorse) their inability or unwillingness to harm the victim in the future (McCullough, Worthington, & Rachal, ), though these eff ects are more diffi cult to demonstrate experimentally between strangers in laboratory settings (Lount, Zhong, & Murnighan, ; Risen & Gilovich, ).
At the neural level, mutual cooperation during prisoner’s dilemmas is supported by brain regions involved in motivating the pursuit of reward (e.g., nucleus accumbens, caudate nucleus, ventromedial frontal/orbitofrontal cor- tex, and rostral anterior cingulate cortex; Rilling et al., ; Rilling, Sanfey, Aronson, Nystrom, & Cohen, ), and is partially dependent on serotonin (Wood, Rilling, Sanfey, Bhagwagar, & Rogers, ).
Social psychologists have identifi ed several other factors that infl uence cooperation in prisoner’s dilemma-type situations. For example, the ability to communicate (and, therefore, coordinate) with an interaction partner fosters cooperation in prisoner’s dilemma-like contexts (Kiesler, Sproull, & Waters, ; Steinfatt, ), especially when people can make mistakes in imple- menting their prosocial intentions (Tazelaar, Van Lange, & Ouwerkerk, ). In addition, people cooperate more with ingroup members than with outgroup members when sharing limited resources (Van Vugt, Snyder, Tyler, & Biel, ), perhaps because ingroup members are seen as more trusting than outgroup members (Turner, Oakes, Reicher, & Wetherell, ).
Indirect Reciprocity
Th e evolution of direct reciprocity requires a relatively high probability of future interactions among individuals who are taking turns helping each other, but there is a kind of prosocial behavior that can evolve even when the benefactor and benefi ciary have zero likelihood of meeting again. Indirect reciprocity occurs when a benefactor acquires a good reputation for providing help to peo- ple in need; this encourages other individuals to help the benefactor in the future (Nowak, ). Experimental evidence shows that people tend to help, donate, or cooperate more frequently with individuals who have reputations for having been helpful or cooperative with others in the past (Seinen & Schram, ; Wedekind & Milinski, ).
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1 According to Nowak (), when the probability q of knowing a benefac- tor’s history of helpfulness toward others exceeds the ratio of the costliness of the benefactor’s act of helping relative to its benefi t to the recipient (c/b), natu- ral selection favors the evolution of mechanisms that promote indirect reci- procity. Indirect reciprocity seems like an important candidate for explaining prosocial behavior in humans because our languages are replete with personal- ity descriptors for conveying information about other people’s generosity (e.g., soft -hearted) and stinginess (e.g., tight-fi sted). Moreover, people are indeed more prosocial when their partners have the ability to spread information to others about their generosity and selfi shness (Piazza & Bering, ; Sommerfeld, Krambeck, Semmann, & Milinski, ).
Signaling Th eory
Signaling theory seeks to explain the evolution of prosocial behavior by virtue of its ability to convey information to others about a benefactor’s hidden (i.e., genotypic) qualities (McAndrew, ), such as his or her intelligence, physical strength, resourcefulness, or value as a mate or coalition member (Gintis, Smith, & Bowles, ; Smith & Bleige Bird, ). A diff erential preference for associating with individuals who have signaled such hidden traits might pro- vide benefi ts to benefactors that off set the costs of the generous behavior itself. In a signaling account of prosocial behavior, signalers receive fi tness benefi ts from sending information, receivers benefi t from decoding it and using it, and both signalers and receivers have evolved psychological systems that are dedi- cated to these purposes (Maynard Smith & Harper, ).
In support of signaling models for prosocial behavior, Iredale, Van Vugt, and Dunbar () found that men were more generous in donating their earnings from a laboratory task to charity when a female observer was present than when a male observer or no observer was present, which led the researchers to propose that gen- erosity in such contexts might result from a system design to advertise an otherwise hidden psychological quality (e.g., empathy or the ability to share) that was relevant to their mate value. Likewise, people are more cooperative with attractive than unat- tractive members of the opposite sex, and such cooperative behaviors makes coop- erators seem particularly attractive (Farrelly, Lazarus, & Roberts, ).
Group (or Multilevel) Selection Th eory
Another evolutionary model that has infl uenced recent research on prosocial behavior is the theory of group selection, increasingly known as “multilevel
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1 selection theory.” For the fi rst years of the twentieth century, many biolo- gists assumed that natural selection took place at the level of both individuals and groups, but with the publication of Williams’s () Adaptation and Natural Selection, the concept of group selection became anathema to evolu- tionary biologists on the grounds that, even if theoretically plausible, the assumptions governing its tenability were so restrictive as to make it ignorable in practice.
Th e assumptions of group selection have been revisited in recent years (Wilson & Wilson, ), and Williams himself () went on to soft en his position on the ignorability of group selection as an evolutionary force. Wilson and Wilson () summarized the foundational claim of multilevel selection in this way: “Selfi shness beats altruism within groups. Altruistic groups beat selfi sh groups” (p. ). In the same way that individual-selection models of altruism posit that fi tness benefi ts redound to individuals with prosocial phe- notypes as a result of their prosocial behavior, group-selection or multilevel selection models posit that some fi tness benefi t redounds to groups with high levels of prosocial behavior relative to other groups. As a result, groups with higher levels of prosocial behavior will become more common whereas groups with lower levels of prosocial behavior will become less common.
Nowak () explained that the mathematical feasibility of group- selection models of prosocial behavior requires more restrictive assumptions than other models do (for example, one must assume that as soon as a group reaches a certain size, it splits in two and one of the two resultant groups replaces another group within a population, with the consequence that the number of groups within a population remains constant). Although critical tests of the utility of multilevel (or group selection) theory for explaining the evolution of prosocial behavior in humans are diffi cult to specify, group-selection accounts of altru- ism require that altruists () can identify each other, () tend to preferentially associate with each other, and () outcompete groups of nonaltruists. Th ese requirements appear to be fulfi lled in social relations among children and adults (Gürerk, Irlenbusch, & Rockenbach, ; Pradel, Euler, & Fetchenhauer, ; Sheldon, Sheldon, & Osbaldiston, ).
Intermezzo on the Current Diffi culty of Reconciling Functionalist and Nonfunctionalist Accounts of Prosocial Behavior
Social–psychological research on prosocial behavior predates psychologists’ more recent interest in applying evolutionary concepts to prosocial behavior.
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1 It can be jarring to move from the tight selectionist and functionalist logic of evolutionarily informed research on prosocial behavior to the constructs and theoretical apparatus that have historically driven social–psychological research on prosocial behavior, so readers should prepare for an abrupt transition to a rather diff erent approach to the social psychology of prosocial behavior. Terminology is also used quite diff erently. For example, what biologists mean by altruism is very diff erent from how that term is used in the mainstream social psychology literature.
It would be good to see some reconciliation between these two approaches to studying prosocial behavior, but the diffi culty of doing so is compounded by the fact that the research fi elds with an interest in the evolution of prosocial behavior (e.g., economics, anthropology, ecology, and evolutionary biology) have themselves not reached consensus on many basic issues. For example, there is no consensus on how specifi c forms of prosocial behavior should be named and defi ned, how carefully the costs and benefi ts to interactants should be specifi ed, the extent to which short-term benefi ts can be taken as proxies for lifetime reproductive fi tness, and even whether a behavior should be described as “prosocial” if it did not evolve in response to selection pressures for prosocial behavior (West, Griffi n, & Gardner, ). To wit, consider the elephant’s production of dung (which dung beetles can then use to their benefi t). Is the ele- phant behaving prosocially toward the dung beetle by producing dung? One should answer affi rmatively unless one has defi ned prosocial behavior at the outset as “the output of a behavioral system that evolved to deliver benefi ts to others” (West, Griffi n, & Gardner, ). One can hardly criticize social psychologists for failing to make more incisive contributions to the interdisciplinary science of prosocial behavior when those more evolutionarily minded disciplines’ own con- ceptual house is in such disarray. We will not solve these problems here, but we will point out some places in which more conceptual clarity might help social psychol- ogy increase its impact on the interdisciplinary science of prosocial behavior.
Reciprocity and Fairness: Two Norms for Prosocial Behavior
One cannot go far in the history of research on the social psychology of proso- cial behavior without encountering the concept of norms. Norms are written or unwritten rules for appropriate behavior that people internalize through direct punishment, direct reinforcement, or social learning (Batson, ; Gürerk, Irlenbusch, & Rockenbach, ; Weber & Murnighan, ), and they are regularly enforced in hunter–gatherer groups whose lives closely resemble
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1 those of ancestral humans (Boehm, ). Social psychologists have concen- trated on two norms that help to explain many of the prosocial behaviors that are favored and for which violations are regularly punished cross-culturally: the norm of reciprocity and the norm of fairness.
Th e Norm of Reciprocity
Th e norm of reciprocity is the obligation to benefi t (and refrain from harming) people from whom one has received benefi ts in the past (Gouldner, ). Th ere is also a norm of negative reciprocity, thought to be equally universal and infl uential, that compels people to return harm for harm (Eisenberger, Lynch, Aselage, & Rohdieck, ). Reciprocity norms are believed to be cross-culturally universal features of humans’ moral sensibilities (Brown, ; Triandis, ), and may refl ect how the evolved psychological processes that govern eff ective reciprocal altruism (Axelrod, ) give rise to culture.
In an early study of the reciprocity norm, Pruitt () showed that the amount of helping that people reciprocate in laboratory situations is () a direct function of the amount they had previously been given, () an inverse function of the total amount of resources the benefactor had to give, and () a direct function of the amount of resources the benefactor would have to give in the future. Th ese fi ndings suggest that people are motivated to provide benefi ts in order to repay debts—especially generous ones—and also to maintain their standing as good candidates for future exchange.
Th e Norm of Fairness
Th e norm of fairness refl ects a deep aversion to unequal treatment. Brosnan and de Waal () trained capuchin monkeys to exchange tokens for food, and they showed that aft er monkeys who had been trained to exchange tokens for pieces of cucumber witnessed other monkeys who were able to trade tokens for grapes (a more highly valued food item) the monkeys either () refused to continue trading tokens or () rejected the cucumber pieces completely. Likewise, people are much less cooperative in iterated prisoner’s dilemmas when their partners systematically receive better payoff s than they do (Sheposh & Gallo, ). Anger and resentment are associated with feeling underbene- fi ted (Hassebrauck, ), as is increased disapproval of the overbenefi ted part- ner (Sheposh & Gallo, ). Conversely, enhancing people’s confi dence that a public good will be distributed fairly among contributors increases contribu- tions (Eek & Anders, ).
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1 According to equity theory (Walster, Berscheid, & Walster, ; Walster, Walster, & Berscheid, ), people are motivated to preserve equity, which these theorists defi ne as a state in which the ratio of outcomes to inputs is equal for all of the individuals involved in a relationship. A prediction from equity theory about Brosnan and de Waal’s () capuchin monkeys trading tokens for money is that the monkey receiving cucumber (the worse outcome) instead of grapes (the better outcome) could potentially be satisfi ed with that arrange- ment if the experimenters reduced the number of tokens needed to trade per unit of cucumber so that the two monkeys’ ratios of outcomes (value received) to inputs (number of tokens traded) were equal. Th ings can be equitable even if they are not identical.
When people’s cost/benefi t ratios become markedly lower than those of their partners (i.e., when they are overbenefi ted), they oft en feel guilty (Austin, McGinn, & Susmilch, ) and become motivated to reduce the inequity. One prosocial thing partners who are feeling overbenefi ted might do to reduce the inequity is to try to help their partners increase their benefi ts or reduce their inputs. Th ey might also engage in indirect prosocial behavior. Wayment (), for example, found that people who reported higher levels of survivor guilt and grief following the September terrorist attacks engaged in collective helping more so than people who reported less survivor guilt and grief. Relatedly, Berscheid and Walster () showed that people are motivated to provide benefi ts to people they have inadvertently harmed in proportion to the amount of harm done. Conversely, people who feel underbenefi ted relative to their inputs may respond to the perceived inequity in many ways, including reducing their eff ort, trying to renegotiate a better deal, or exiting the relationship and trying to fi nd a new one.
Equity theory has been modifi ed substantially since its initial formulation and has well-known limitations. For example, equity concerns are less salient in relationships with high degrees of interpersonal commitment and self-other overlap and in relationships for which partners have poor alternatives (Buunk & Bakker, ; Medvene, Teal, & Slavich, ; Rusbult, , ). Nevertheless, equity retains some degree of importance even in highly commit- ted relationships (Sprecher, ), especially when partners have an exchange orientation to the relationship or to relationships in general (Buunk & Van Yperen, ). It is also clear that people diff er in the extent to which they are oriented toward a communal view of relationships (Clark, Ouellette, Powell, & Milberg, ), and these individual diff erences should be considered as impor- tant moderators of people’s responses to inequity. Recently, Tabibnia, Satpute, and Lieberman () made some progress in identifying brain regions that support calculations of fairness and unfairness in social exchange (viz., areas involved in reward computation and emotion regulation).
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1 Motives for Prosocial Behavior
Social psychologists oft en study prosocial behavior by examining the motives that stimulate it. One of the greatest distinctions is between prosocial behavior that is motivated by so-called egoistic concerns and behavior that is motivated by so-called altruistic concerns (and it is here we see the term “altruism” used very diff erently from its usage in biology). Batson, Ahmad, Powell, and Stocks () described three types of egoistic motivations for prosocial behavior: () the motivation to receive material, social, and self-administered rewards (such as payment, gift s, credit for future help from reciprocal altruism partners, enhanced self-esteem, or imagined religious rewards); () the motivation to avoid material, social, and self-administered punishments (e.g., fi nes/imprisonment, attacks, social sanctions for violating norms, or shame); and () the motivation to reduce aversive arousal (including distress associated with witnessing other people’s pain and suff ering).
Rather than assuming that every instance of helping has an egoistic motiva- tion at its root, theorists from the altruistic tradition in social psychology hypoth- esize instead that “at least some of us, to some degree, under some circumstances, help with an ultimate goal of benefi ting the person in need” (Batson, Ahmad, & Lishner, , p. ). (Evolutionarily minded readers will notice, too, the very diff erent way in which the concept of “ultimate” is used in this quotation. Evolutionary thinkers would typically look for the ultimate causes of prosocial behavior in the selectionist models we enumerated earlier—all of which, ulti- mately, turn on the fact that mechanisms designed for prosocial behavior could have evolved only because their ultimate cause was that they increased the fi tness of their bearer, on average, during evolution.) Th e number of egoistic models for prosocial motivation that have been advanced over the years is overwhelming, so here we limit ourselves to describing two of the more infl uential ones, plus an altruistic alternative and some of the critiques that have been leveled against it.
Th e Negative State Relief Model
Cialdini, Darby, and Vincent () proposed a “negative state relief ” model that specifi es that people help others to reduce their own distress by experienc- ing the countervailing positive emotions that come from helping someone in need. Th ese researchers found that people who had either () harmed someone or () witnessed someone experiencing harm (both of which presumably led to negative moods, although for diff erent reasons) subsequently engaged in more prosocial behavior than did people in a control group who had not perpetrated
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1 or witnessed any transgressions against others—but only if they had not expe- rienced an intervening situation that improved their moods (i.e., the receipt of money or social approval). Furthermore, there is evidence that under certain conditions, helping can elevate one’s mood (Gebauer, Riketta, Broemer, & Maio, ; Midlarsky, ; Williamson & Clark, ). Conversely, several studies have also shown that inducing positive aff ect increases helping behaviors (Carlson, Charlin, & Miller, ), perhaps because people want to ensure that their good moods will not be spoiled by someone else’s suff ering (Batson, Ahmad, Powell, & Stocks, ).
Th e Arousal: Cost-Reward Model
Piliavin and colleagues (Dovidio, Piliavin, Gaertner, Schroeder, & Clark, ; Piliavin, Dovidio, Gaertner, & Clark, ) developed the “arousal: cost-reward theory” to explain when people are likely to help in emergency situations. Th e negative state relief model, however, involves helping to enhance one’s mood— regardless of the reason for the bad mood; based on the arousal: cost-reward theory, emergency helping is the result of a motivation to eliminate the negative aff ect specifi cally due to witnessing the physical or emotional distress of the person in need.
Th e arousal: cost-reward theory specifi es three conditions under which emer- gency assistance should be most likely. First, the more aversive arousal people feel in an emergency situation, the more likely they will be to provide help (Dovidio, ; Gaertner & Dovidio, ). Second, people will be more likely to help when the victim and the helper share similarities, common group identities, or feelings of relatedness or closeness. Th ird, the model specifi es that emergency helping will be more likely when the costs of doing so are low relative to the hedonic rewards that will come from helping. When the costs of helping become too high—for example, if the person in need is bleeding and the helper may have to come in contact with blood (Piliavin & Piliavin, ), or when their levels of arousal are heightened by the fact that the person in need is of a diff erent race than they are (Kunstman & Plant, ), people may choose other methods for reducing their negative arousal (e.g., trying to ignore the person’s plight or leaving the scene) (Dovidio, Piliavin, Gaertner, Schroeder, & Clark, ).
Th e Empathy-Altruism Hypothesis
Batson and colleagues have repeatedly tested the hypothesis that humans have an “altruistic motivation” for helping that is reliably elicited by empathy for the
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1 person in need. Batson et al. () defi ne empathy as “an other-oriented emo- tional response elicited by and congruent with the perceived welfare of some- one else” (p. ). Empathy for another person can be enhanced by observing or imagining the person’s aff ective state (de Vignemont & Singer, ), by sharing emotions, feelings or sensations (Preston & de Waal, ), by valuing another person’s welfare (Batson, Eklund, Chermok, Hoyt, & Ortiz, ; Batson, Turk, Shaw, & Klein, ), and by recognition of kinship, similarity, or closeness (Cialdini, Brown, Lewis, Luce, & Neuberg, ). In the laboratory, empathy for complete strangers is elicited most commonly (and with the least apparent risk of confounding with other processes) through a two-step process: fi rst, exposing a participant to someone else’s need; and second, instructing the participant to imagine how the person in need is feeling (Batson, ; Batson, Turk, Shaw, & Klein, ). At the neural level the experience of empathy for some- one in distress is supported by some of the same brain regions that are involved in the distress that people feel when experiencing pain or discomfort (e.g., bilateral anterior insula and rostral anterior cingulate cortex; Singer et al., ).
Empathy reliably elicits helping (Coke, Batson, & McDavis, ), but this fact does not imply that the motivation underlying empathy-induced helping is to improve the welfare of the person in need: Th e underlying goal could be, for example, reducing one’s own empathic arousal, or avoiding social or self- imposed punishments associated with failing to help, or gaining social or self- approval. Batson and colleagues (and their detractors) have conducted more than experiments to evaluate these motivations over the past several decades. In one of the earliest studies (Batson, Duncan, Ackerman, Buckley, & Birch, ), they induced empathy in participants by telling half of the sample that they had values and interests similar to a confederate named Elaine, who would be receiving random electric shocks as part of the experimental procedure. Before the study began, Elaine and the experimenter had a conversation (that they intended the participant to overhear) in which Elaine described her appre- hension about receiving the shocks due to a traumatic event that she had expe- rienced in the past. Aft er two trials participants were then asked if they would be willing to trade places with Elaine to help her avoid more suff ering.
To test an egoistic explanation derived from negative state relief theory, the researchers manipulated how diffi cult it was for the participants to escape the situation (in the easy escape condition, participants could fi nish the study aft er the fi rst two trials; in the diffi cult escape condition, participants could not leave until all trials were completed). Participants in the low-empathy group were more likely to opt out when doing so was easy; however, when it was diffi cult, half of them agreed to trade places with Elaine. In support of the empathy- altruism hypothesis, the majority of those in the high-empathy group agreed to trade places with Elaine irrespective of whether it was easy for them to escape.
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1 Other experiments using perspective-taking manipulations of empathy (for review see Batson, ) have likewise demonstrated that inducing empathy causes people to help even when escape is easy, which suggests that participants are able to accomplish their empathically induced goal only by helping the par- ticipant (rather than by escaping the situation). Th ese results cast doubt on the tenability of the hypothesis that the motivation underlying empathically induced helping is the escape of aversive arousal (Batson, Ahmad, Powell, & Stocks, ). Batson et al. () likewise concluded that experiments testing the possibility that empathy-induced helping was motivated by the goal of avoiding social or self-administered punishments for failing to help have con- sistently supported the empathy-altruism hypothesis.
Research on the possibility that empathically induced helping has as its goal the rewards (either self-administered or from other people) associated with helping someone else has been a bit more controversial, with some researchers claiming confi rmation (Cialdini et al., ; Schaller & Cialdini, ; Smith, Keating, & Stotland, ) and others claiming refutation based on method- ological limitations in the studies that supposedly supported the egoistic alternative, along with experimental data that surmount those methodological limitations (Batson et al., , ; Dovidio, Allen, & Schroeder, ; Schroeder, Dovidio, Sibicky, Matthews, & Allen, ). Nevertheless, even Cialdini and colleagues () have acknowledged that the argument for the existence of an altruistic motivation in human nature “does appear to have won the war in important respects” (p. ).
Who Provides Help?
Some people are more prosocial than others. Some stop at the scene of acci- dents to render fi rst aid, or donate to charities, or volunteer in their communi- ties. Others do not. Researchers have tried to explain these individual diff erences in terms of () prosocial personality traits; () sex diff erences; and () genetic and neuroendocrine factors.
Prosocial Personality Traits
Individual diff erences in trait empathy are associated with individual diff erences in prosocial behavior (Davis et al., ) and empathy and other prosocial traits are stable over time (Eisenberg et al., ). Based on fi ndings such as these, Penner, Fritzsche, Craiger, and Freifeld () proposed that the prosocial
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1 personality consists primarily of a suite of personality traits including () a sense of responsibility, () empathy, and () the self-perception that one is capable of being helpful across diverse situations. In addition, believing in a “just world” (Furnham, )—the idea that people ultimately get what they deserve—may infl uence prosociality. People who believe in a just world may help others when they believe that others deserve their help (Zuckerman, )—though they may be less likely to help people whose plights they perceive to be largely self-created (Lerner, , ).
Bierhoff , Klein, and Kramp’s () study illustrates some of these points. Th ey studied the personality diff erences between a group of people who had stopped to render aid at traffi c accidents and a group of other people (matched on age, sex, and socioeconomic status) who had witnessed similar accidents but had not stopped to help. Helpers described themselves as having more internal loci of control, stronger beliefs in a just world, and higher empa- thy. Similarly, Oliner and Oliner () and Fagin-Jones and Midlarsky () found that non-Jews who had aided or rescued Jews during the Holocaust reported more empathy and feelings of social responsibility (and were more likely to see all people as equal) than did a group of age- and sex-matched non-Jews who did not.
Th e prosocial traits proposed by Penner et al. () overlap to some extent with the “Big Five” (John, ) or “Five-Factor” (McCrae & Costa, ) per- sonality dimension known as Agreeableness (Penner et al., ), which itself is a reliable predictor of prosocial behavior (e.g., Graziano, Habashi, Sheese, & Tobin, ). Highly agreeable people tend to be more aware of the mental states of others, which may be one of the mechanisms responsible for their prosociality (Nettle & Liddle, ). Graziano and colleagues () also found that people high in agreeableness tended to off er more help across a wider range of situations. Agreeable people also engage in more active implicit emotion regulation when confronted with aggressive or antisocial stimuli, which helps them to respond more prosocially to such stimuli (Meier, Robinson, & Wilkowski, ).
Sex Diff erences
Men render more aid in social psychology experiments (when helping is mea- sured in terms of behaviors such as giving money to a stranger, stopping a man from stealing someone’s calculator, or helping someone who has dropped some envelopes) than women. In a meta-analysis of the extant studies, which evalu- ated diff erent predictors of between-study variation in eff ect size, Eagly and Crowley () found that a medium-sized gender diff erence favoring men
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1 (d = .) could be expected in a study with typical values on all moderators. Th ey also found that this eff ect would be expected to be even larger in experi- ments conducted outside university campuses.
But the fact that men tend to provide more help in social–psychological experiments should not be taken as evidence that men are more prosocial across the board than women. Women have more empathy for others than men (Eisenberg & Lennon, ), and longitudinal studies also indicate that girls demonstrate higher levels of prosocial behavior than boys (Gregory, Light- Hauserman, Rijsdijk, & Eley, ; Zahn-Waxler, Schiro, Robinson, Emde, & Schmitz, ). Women also provide more emotional and instrumental social support to people in their social networks (including family and friends) than do men—particularly under times of stress (Taylor et al., ). Additionally, they perform more caregiving (particularly in terms of personal care and household tasks) for older adults than do men (Miller & Cafasso, ). On the basis of gender diff erences such as these, Taylor and colleagues (Taylor, ; Taylor, Dickerson, & Klein, ; Taylor et al., ) have hypothesized evolved sex diff erences in biological systems designed to mobilize nurturance and social support, which arose due to selection pressure for women to provide care for their off spring during stress (see Taylor, Chapter , this volume).
Women are also more likely to provide heroic, life-threatening forms of care to strangers than the laboratory experiments indicate. Although men are overwhelmingly more likely to engage in life-threatening acts of heroism of the sort that might win them a nomination for a Carnegie Hero Fund Award (these awards are given to civilian adults who voluntarily, and outside of job responsi- bilities, knowingly risk their lives to rescue unrelated individuals form life- threatening situations such as fi res, drownings, and attacks by animals or criminals) relative to any conceivable base rate for their presence in the settings that give rise to such emergencies, Becker and Eagly () demonstrated that there are several forms of risky helping behaviors for which women are over- represented. For example, among unmarried people in Poland, the Netherlands, and France during World War II (i.e., when married couples are excluded from the calculations), unmarried non-Jewish women were approximately % more likely than unmarried non-Jewish men to risk their life, freedom, or safety to rescue Jews from the Holocaust (these and all comparable statistics below are adjusted for men’s and women’s representation in the general population). Becker and Eagly also documented that women are approximately % more likely than men to donate kidneys, approximately % more likely than men to serve in the Peace Corps, and about twice as likely to serve as physicians with Doctors of the World relative to their representation among all physicians in the United States.
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1 From these data, Becker and Eagly made the point that although men’s physical strength, capacity for fast action, (possibly) better training for infor- mal lifesaving (e.g., through the Boy Scouts or military training), and diff eren- tial responsiveness to the reputational incentives associated with being publicly acknowledged as heroes might lead them to engage in more emergency helping in many public settings, women’s tendency to help more than men in the other risky situations that Becker and Eagly documented might refl ect women’s higher levels of empathy or (we take them to mean, as a by-product of) a female-specifi c adaptation for providing nurturance to off spring during times of stress (see also Taylor et al., ).
Genetic and Neuroendocrine Factors
Behavioral-genetic studies indicate that prosocial behavior (at least as mea- sured by self-reports and informant reports of traits such as trust, empathy, cooperation, and altruism) has a substantial genetic component (Gillespie, Cloninger, Heath, & Martin, ; Gregory, Light-Hauserman, Rijsdijk, & Eley, ; Matthews, Batson, Horn, & Rosenman, ; Rushton, Fulker, Neale, Nias, & Eysenck, ). Additive genetic factors appear to account for roughly % to % of the variation in adults’ prosocial behavior, with the remainder largely attributable to nonshared environmental factors (Gregory, Light- Hauserman, Rijsdijk, & Eley, ).
With the widened availability of genomic methods to behavioral scientists, researchers have begun to identify several genes that are associated with proso- cial behavior. In a sample of multisibling families, Bachner-Melman and colleagues () found associations between selfl essness (e.g., less concern for one’s own needs, greater attendance to the needs of others) and the dopamine D and dopamine D receptor polymorphisms. Other researchers have found evidence that individual diff erences in the receptor genes for vasopressin and oxytocin are associated with individual diff erences in prosocial behavior (Israel et al., ; Knafo et al., ).
Who Receives Help?
In social psychology experiments, women in need receive more help than men in need. Based on a meta-analysis of data from experiments, Eagly and Crowley () estimated that women receive . standard deviations more
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1 help than men in similar need situations, but aft er controlling for potential moderators of between-study variability in their meta-analytic results, Eagly and Crowley found that women could be expected to receive a whopping . standard deviations more help than men generally receive.
People also tend to help people with whom they are similar (Park & Schaller, ). In addition, people are more likely to give help to members of groups to which they belong. For example, white people wait longer to provide emer- gency help (i.e., they provide help less immediately) to a black person than they do to a white person—particularly in high-emergency situations (Kunstman & Plant, ).
Finally, both men and women provide more help to attractive people than to unattractive people (Benson, Karabenick, & Lerner, ; Dovidio & Gaertner, ; Farrelly, Lazarus, & Roberts, ; West & Brown, ). Stürmer, Snyder, and Omoto () found that the attractiveness of the target to be helped was a particularly important mediator of helping when that person (who was of the same gender as the participant) was a member of a group to which the participant did not belong (e.g., when the potential helper was het- erosexual and the potential target of helping was same-gender homosexual, and vice versa). When the helper and target of helping were from the same social group (i.e., when both were either heterosexual or homosexual) empathy predicted helping better than did attractiveness.
Environmental and Situational Factors
Th ere are many environmental and situational factors that infl uence prosocial behavior. For example, all over the world, people in cities are signifi cantly less helpful than people in rural areas (Steblay, ). Levine, Martinez, Brase, and Sorenson () conducted a study of helping behaviors in U.S. cities and found that population density was a more important predictor than overall population size. A common explanation for this fi nding is that with increased population density, people become fatigued by unwanted distractions and interruptions and therefore begin to psychologically close themselves off to interactions with strangers, which causes them to become less responsive to people who might be in need of help (Milgram, ).
In a cross-cultural study of helping in large world cities (e.g., Budapest, Rio de Janeiro, Tel Aviv, New York), Levine, Norenzayan, and Philbrick () found substantial cross-cultural diff erences in the extent to which people would () stop to pick up a pen that a confederate had dropped, () help or off er to help a confederate wearing a leg brace to pick up a pile of magazines he had
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1 dropped, and () help a seemingly blind confederate cross the street. Th e best predictor of cross-cultural diff erences in helping was purchasing power parity (PPP), which measures economic development. Cities in nations with the highest PPP had the lowest rates of helping (r = –. with the mean of all three measures of helping). Rates of helping were not signifi cantly correlated with the cities’ pop- ulation sizes, pedestrians’ mean walking speed (used as a proxy for pace of life), or culture-level measures of individualism and collectivism. Levine et al. () suggested that with economic development comes the replacement of traditional value systems that emphasized the importance of helping strangers.
Time Pressure
Time pressure also infl uences emergency helping. In an infl uential early study on this topic, Darley and Batson () assigned seminary students to low, moderate, and high “hurry” conditions. Th e students, who were on their way to give a talk about the Good Samaritan parable (a story in the Christian Bible about a man who stopped to help someone from a diff erent ethnic group who was very ill) or about a control topic, passed a confederate who looked unwell. Darley and Batson found that % of seminarians who were not rushed stopped to help, whereas only % of those who were running late stopped to help. Th e topic of the seminarians’ upcoming talks did not signifi cantly infl uence what they did (but see Greenwald, , who argued that there was in fact an impor- tant eff ect for the topic of the talk that was masked by low statistical power. We wonder why no one ever noted Greenwald’s suggestion and explored the issue further.).
Ambiguity of Need
Shotland and Straw () conducted an experiment in which they staged an altercation between a man and a woman. If the woman shouted “get away from me; I don’t know you,” bystanders helped % of the time. In contrast, if the women shouted “Get away from me; I don’t know why I ever married you,” bystanders helped % of the time.
Th e Bystander Eff ect
Th is takes us to the bystander eff ect—the tendency for people to render less assistance in an emergency as the number of other bystanders increases.
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1 Latané and Darley’s (, ) initial work in this area was stimulated by a New York Times account of the murder of a young woman in Queens, New York, named Kitty Genovese. According to the original report, Genovese was fatally assaulted outside of her apartment, and of her neighbors heard the -minute-long altercation without a single one lift ing a hand to intervene. As the standard telling of the story goes, the assailant left the scene and came back on two diff erent occasions shortly aft erward to continue the attack. However, recent research based on legal documents and testimony from the attacker’s murder trial calls into question many details of the canonical Kitty Genovese story. For example, there were two attacks rather than three; the number of eyewitnesses was fewer than ; several witnesses did call the police aft er the fi rst attack; none of the witnesses would have had the fi eld of view to see the complete -minute episode; the second and fatal attack took place indoors where only a few witnesses would have been able to hear or see any part of it; and the fi rst attack was, in fact, ended by bystander intervention—someone shouted out of a window so that the perpetrator ran off , presumably ending the altercation from many bystanders’ points of view (Manning, Levine, & Collins, ). Nevertheless, the story is still a powerful one that inspired scores of studies on the bystander eff ect and its boundary conditions.
Latané and Darley () proposed that people must successfully negotiate a series of decisions—oft en under conditions of considerable chaos and emo- tional arousal—before rendering aid in a group setting (Batson, ; Latané & Nida, ). Th ey hypothesized that the presence of other people biases each of these decisions toward the choice that would reduce the likelihood of prosocial behavior. First, people must notice that something is happening that requires intervention. If bystanders are uncertain about whether to help, they tend to look to others for guidance. Unfortunately, because no one wants to be embar- rassed by overreacting to a situation that is in actuality not an emergency, it is thought that most people inhibit their expressions of emotion in such situa- tions. As a result, looking to others for cues that an emergency is indeed hap- pening inhibits bystander intervention. Th is is a phenomenon that Latané and Darley () called pluralistic ignorance. Another important social process in these situations is social infl uence, in which other people’s inaction causes peo- ple to conclude that a situation does not, in fact, require intervention. In an experiment involving a confederate whom participants believed was blind, Ross and Braband () found that bystanders continued to react to odorless smoke even if the presumably blind confederate did not. However, bystanders reacted less oft en when the presumably blind confederate did not react to a woman’s scream (i.e., which did not require eyesight).
Having recognized a need, bystanders must then decide they have a per- sonal responsibility to take action. Darley and Latané () conducted an
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1 experiment in which participants engaged in a discussion, when a confederate began to feign a seizure and called for help. Nearly every participant who believed that no one else could hear what was happening tried to help the con- federate, whereas participants in larger groups (six persons) tended not to help. Conversely, participants are more likely to help—even when in the presence of others—if they perceive that the other bystanders are unable to help (Bickman, ). When people know that they are the only ones who are in a position to help, the personal costs of nonintervention become higher, as they know that they will be to blame if the person’s need remains unrelieved.
Finally, even if people decide that they should take action, they may believe that they are incompetent to do so. In the presence of groups, lack of perceived competence can deter off ers of help. Cramer et al. () conducted a study in which half of the participants were registered nurses and the others were gen- eral education students. With the use of confederate bystanders who were instructed not to react, participants passed a worker on a ladder and then heard a noise as if the worker had fallen. Th e nurses helped when in the presence of others or when alone, whereas the general education students were more likely to help if they were alone.
Other variables can also reduce the bystander eff ect. When groups are cohesive, rather than simply an aggregation of strangers, larger groups can actually increase helping behavior relative to smaller groups (Rutkowski, Gruder, & Romer, ). When people are seated face to face, and can easily observe each others’ facial and nonverbal reactions to a potential emergency situation (and so that others can see theirs), helping is higher in the presence of others than when people are seated back to back and thus cannot see each other’s nonverbal expressions of concern (Darley, Teger, & Lewis, ). Finally, people help more in the presence of friends than in the presence of strangers (Latané & Rodin, ) and may even help more when the group shares a common identity with the person in need of help: Men and women both are more likely to help a woman in distress if they have been seated among a group of strangers who were all women (Levine & Crowther, ).
Despite these boundary conditions, the bystander eff ect is robust. Across nearly laboratory experiments, approximately % of people tried to render aid to someone in need when alone, whereas only % of people did so in the presence of others (Latané & Nida, ). But the person in need has a diff erent question: “Will I receive help?” According to Latané and Nida’s () meta- analysis, in situations in which bystanders are able to see, and be seen by, other potential helpers, only % of people in need receive help. In contrast, people in need receive help % of the time when there is a single bystander.
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1 Volunteering
Volunteering is one of the most widely practiced prosocial behaviors. In the United States, approximately % of the population (i.e., million people) volunteered at least once between September and September (U.S. Department of Labor, ). Volunteering is evidently benefi cial for psycho- logical well-being and physical health (Brown, Nesse, Vinokur, & Smith, ; Musick, Herzog, & House, ; Oman, Th oresen, & McMahon, ; Th oits, ). Hansen, Larson, and Dworkin () also found that participation in volunteer activities was associated with personal development (e.g., identity) as well as interpersonal development (e.g., prosocial norms and ties to the com- munity) among an ethnically diverse sample of youth. Among the diff erent types of organizations in which people volunteer, more time is devoted to vol- unteering for religious organizations (.% of all volunteers; U.S. Department of Labor, ).
Some of the best predictors of volunteer activity are the extent to which one feels that volunteering has become an important part of one’s identity and the extent to which one feels that other people are aware of one’s volunteer activities and expect one to continue working as a volunteer (Finkelstein, Penner, & Brannick, ). Volunteering is also associated with higher levels of self- reported empathy, a generally positive orientation toward helping, and religiosity (Penner, ; Penner & Finkelstein, ). Clary and Snyder () further- more suggested that people can have any of six motivations for volunteering (i.e., expressing one’s values, gaining knowledge or understanding, growing or devel- oping psychologically, gaining career-relevant experience, strengthening one’s social relationships, or reducing one’s own negative feelings or addressing one’s own personal problems). Matching people with volunteer opportunities that allow them to fulfi ll their motivations produces greater satisfaction with the experience and increases their intention to volunteer in the future (Clary & Snyder, ; Clary et al., ; Clary, Snyder, Ridge, Miene, & Haugen, ). Also, it is important to note that requiring people to volunteer (e.g., through service learning requirements in high schools) who are not initially motivated to do so reduces their intention to volunteer in the future (Clary et al., ).
Fostering Prosocial Behavior
A considerable amount of research has addressed the factors that foster proso- cial behavior in children and adults. Parental modeling of prosocial behavior is
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1 an important element of prosocial development (Rushton, ). Another aspect of parenting that may foster prosocial behavior is providing reasoned explanations when asking children to change their behavior (Hoff man, ; Krevans & Gibbs, ). Similarly, parental authoritativeness, positivity (indexed by emotionally positive, noncoercive methods of discipline), and emotional availability also appear to play a role in prosocial development (Hastings, Zahn-Waxler, Robinson, Usher, & Bridges, ; Knafo et al., ; Moreno, Klute, & Robinson, ).
Rosenhan and White () conducted a study of fourth and fi ft h graders in which the children played a game once in the presence of an adult model and once without this model. Every time the model won, the model donated half of the earnings to charity. Children who had witnessed the model’s behavior, and particularly those who had also given to charity while in the model’s presence, tended to donate to charity when playing alone. Similarly, Rushton () stud- ied - to -year-old children who had witnessed an adult model play a game and donate a portion of his or her earnings (i.e., tokens) to charity. Two months later the children played one of three games that varied in similarity to the original game. Th e children who viewed the modeling behavior weeks earlier behaved more prosocially (i.e., donated more to charity) across all three game conditions. In addition, children who had been “preached” to during the task about the importance of giving money to the charity donated more money weeks later (even though preaching did not infl uence donations immediately following the game weeks earlier).
In addition, Bryan and Test () found that aft er drivers saw someone stop by the side of the road to help a woman change a fl at tire, they were more likely to stop and help a woman in a similar situation. Likewise, exposure to prosocially oriented television programs (Hearold, ) and video games (Gentile et al., ) can increase prosocial behavior in children and adoles- cents, perhaps through social learning or direct reinforcement: Video games are fun, so playing a video game in which characters have prosocial goals can make helping fun.
Explicit attempts to educate people about prosocial behavior can also make a diff erence. For example, educating others about the bystander eff ect has been shown to increase helping behavior in students (% versus % who did not hear the lecture; Beaman, Barnes, & Klentz, ). Finally, research suggests that subtly priming people with social stimuli such as geometric confi gurations that resemble eyes or faces (Bateson, Nettle, & Roberts, ; Haley & Fessler, ; Rigdon, Ishii, Watabe, & Kitayama, ), reminders of God or religion (Pichon, Boccato, & Saroglou, ; Shariff & Norenzayan, ), and even secular institutions such as contracts and police that regulate prosocial behavior (Shariff & Norenzayan, ) increase generosity, cooperation, and charitable
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1 giving. Th ese eff ects are obtained in both laboratory and fi eld experiments, sug- gesting that some of the lowest-hanging fruit in social psychologists’ eff orts to increase prosocial behavior in the real world might be best be obtained through subtle, nonpreachy stimuli that activate prosocial cognition and behavior without conscious awareness.
Prosocial Behavior Today
Nearly years of research on the social psychology of prosocial behavior has produced a broad and fascinating set of facts and theories about the factors that promote and inhibit prosocial behavior, as well as on interventions that might be applied in the real world to increase prosocial behavior. Th ese concepts con- tinue to attract the attention of social psychologists, and they should. We are confi dent that high-quality social–psychological work on prosocial behavior will continue much in the same fashion it has for the past fi ve decades.
Which is not to say that there is no room for new conceptual directions, because there is. Humans’ penchant for prosocial behavior is one of the great puzzles of evolutionary theorizing, and there is considerable room for further social–psychological research devoted to uncovering the mind’s functional cir- cuitry for producing prosocial behavior. By thinking explicitly about the selec- tion pressures that might have given rise to prosocial behavior and the types of psychological machinery that would be required to produce prosocial solutions in response to those selection pressures, social psychologists may be able to make important new strides in understanding how humans manage to be so prosocial, how those tendencies are thwarted, and the cognitive tools that the mind might possess for producing such remarkable behavior.
Moreover, many important issues in the mainstream social–psychological literature are ripe for evolutionary recasting. From what selection pressures did Batsonian altruistic motivation arise? Does the role of blood in discouraging emergency helping refl ect a confl ict between evolved mechanisms for disgust and evolved mechanisms for reciprocal altruism? Are men so much more likely to render emergency aid in highly public settings because of a desire to signal their value as protectors and providers to a choosy pool of prospective mates? Can the bystander eff ect be better conceptualized as a public goods problem (i.e., it benefi ts me if we have a system in which people can get help, but not if I’m the one who has to do the helping)—which would render it highly amena- ble to evolutionary analysis? Th e fi eld is fi lled with opportunities such as these. Careful reliance on well-established evidentiary criteria for testing adaptation- ist hypotheses (Andrews, Gangestad, & Matthews, ; Williams, ; see
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1 Maner & Kenrick, Chapter , this volume) is essential for doing this job well, and would help put the social psychology of prosocial behavior on a broader theoretical footing that will improve its relevance to both social psychology and the interdisciplinary science of prosocial behavior.
Acknowledgments
Preparation of this chapter was supported by the Center for the Study of Law and Religion at Emory University. Th e authors gratefully acknowledge Rob Kurzban, who provided helpful feedback on a previous version of this chapter.
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Prosocial Behavior
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core topics in social psychology
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