Helping Behavior

Abstract

Helping behavior is a form of social behavior: voluntary action that benefits another person, whether a stranger in an emergency or a familiar other in need. The field turns on two questions—when do people help, and why. This article develops its main threads: the situational analysis of bystander intervention and the diffusion of responsibility that suppresses it; the empathy–altruism hypothesis that empathic concern can motivate genuinely other-oriented helping; the egoistic alternatives, including negative-state relief, that explain the same acts selfishly; the evolutionary and economic accounts of human altruism; the early developmental emergence of helping in infancy; and the individual and gender differences that shape who helps. A worked example and three interactive demonstrations make the mechanisms manipulable.

Keywords: helping behavior, social behavior, bystander effect, empathy–altruism, prosocial behavior

Few acts seem simpler than helping someone, and few have proved harder to explain. A person collapses on a crowded street; a child struggles with a task just out of reach; a stranger drops an armful of papers. Sometimes help comes at once, sometimes not at all, and the difference rarely tracks how kind the onlookers are. The murder of Kitty Genovese in 1964, reported—inaccurately, as it turned out—to have been witnessed by dozens who did nothing, set off a research programme that reframed helping from a question about character into a question about situations and minds.

What the behavioural sciences brought to the topic is a pair of distinct questions that are easy to run together. The first is situational: given that a person could help, what features of the moment make them more or less likely to? The second is motivational: when a person does help, what is the goal of the behavior—to benefit the other, or ultimately to benefit the self? The sections below take these in turn, from the bystander situation through the empathy–altruism debate and its egoistic rivals to the evolutionary, developmental, and individual-difference accounts—after first placing helping within the broader category of social behavior under which it is classified.

What Helping Behavior Is

Helping behavior, in the sense the behavioural sciences study it, is voluntary action undertaken to benefit another person. It is the concrete, observable core of the broader family of prosocial behavior—the full range of acts intended to benefit others, from sharing and comforting to cooperating and donating—and it shades into altruism when the helper's motivation is other-oriented rather than self-serving (Penner et al., 2005). The three terms are often used loosely, but the distinctions matter: prosocial behavior names the category of acts, helping names the behavior itself irrespective of motive, and altruism names a motivational claim about why the behavior occurs.

Two questions organise the field, and keeping them apart is the key to reading the literature. The situational question asks what features of a moment make helping more or less likely—the number of onlookers, the clarity of the emergency, the cost of intervening—and is answered without reference to the helper's ultimate goal. The motivational question asks what the helper is trying to achieve: to improve the other's welfare as an end in itself (altruism), or to gain some benefit, or avoid some cost, for the self (egoism). A single act of helping can be situationally promoted and egoistically motivated at the same time, which is why the two questions require different methods and yield different debates. The field that works on them is large and well mapped; the standard reference synthesis gathers the situational, motivational, evolutionary, and developmental lines of evidence that the rest of this article takes in turn (Schroeder & Graziano, 2015).

In the Medical Subject Headings vocabulary, Helping Behavior is a descriptor defined as behaviour that assists or benefits others, filed under Social Behavior. The placement is apt: helping is social through and through, defined entirely by its orientation toward another party and shaped by the relationship between helper and recipient. The remainder of this article takes the mechanisms of helping in turn—the bystander situation, the empathy–altruism hypothesis and its egoistic rivals, the evolutionary and developmental roots, and the individual differences—and connects each to the cognition and motivation it requires.

Perspectives on Helping Behavior

The study of helping is organised less by one grand theory than by a set of complementary perspectives, each tied to a distinct question. A situational perspective asked when bystanders intervene, and answered in terms of the number of onlookers, the interpretation of the event, and a cost–reward calculus. A motivational-altruistic perspective asked whether helping can ever be genuinely other-oriented, and answered that empathic concern evokes altruistic motivation. A motivational-egoistic perspective answered the same question the other way, explaining helping as relief of the helper's own aversive arousal. An evolutionary-economic perspective asked how a costly disposition to help strangers could arise and persist, and answered in terms of reciprocity and the punishment of free-riders. A developmental perspective asked when helping first appears, and found it strikingly early. Table 1 summarises them, and the sections that follow develop each in turn.

Table 1

Perspectives on Helping Behavior

The Bystander Situation

The founding discovery of the modern field is that whether a person helps in an emergency depends less on who they are than on how many others are present. John Darley and Bibb Latané staged emergencies—a victim apparently having a seizure, heard over an intercom—and varied the number of bystanders the participant believed were also present. The more bystanders a participant thought there were, the less likely they were to intervene and the longer they took when they did: with the participant alone, 85% responded; with others ostensibly present, the rate fell sharply (Darley & Latané, 1968). They named the mechanism diffusion of responsibility: when responsibility to act is shared among many, each person bears less of it, and the obligation that would compel a lone witness dissolves.

Latané and Darley modelled intervention as a sequence of five steps—notice the event, interpret it as an emergency, assume responsibility, decide one knows how to help, and act (Figure 1)—with the group suppressing helping at two of them. At the interpretation step, each onlooker looks to the others for cues and, seeing them outwardly calm, concludes nothing is wrong: a shared misreading the field calls pluralistic ignorance. At the responsibility step, diffusion sets in. Irving Piliavin and colleagues then carried the question out of the laboratory and onto the New York subway, staging collapses and recording who helped: help in this face-to-face setting was in fact frequent and fast, and depended on the apparent cause of the victim's distress—a person who seemed ill was helped more readily than one who seemed drunk (Piliavin et al., 1969). Demo 1 lets the reader vary the number of bystanders and read off how diffusion of responsibility lowers each individual's probability of helping.

The Empathy–Altruism Hypothesis

If the situational work asked when people help, Daniel Batson asked why—and in particular whether helping is ever genuinely for the other's sake. His empathy–altruism hypothesis holds that feeling empathic concern for a person in need (sympathy and compassion oriented toward their welfare, as distinct from the personal distress their plight causes in oneself) evokes motivation with the other's welfare as its ultimate goal (Batson et al., 1981). The experimental strategy was ingenious: because egoistic motives to help are satisfied by escape as readily as by helping, Batson varied how easy it was for participants to leave the situation. Under low empathy, helping tracked escape—people helped when they could not easily leave and left when they could—the egoistic signature. Under high empathy, people helped whether or not escape was easy, the pattern predicted only if their goal was the victim's welfare rather than their own relief.

The converging evidence from developmental and individual-difference research strengthened the case. Nancy Eisenberg and Paul Miller, reviewing decades of studies, found that empathy—and especially other-oriented sympathy—is positively, if modestly, related to prosocial behavior across ages and methods, with the relation strongest when empathy is measured in ways that capture concern for the other rather than mere emotional contagion (Eisenberg & Miller, 1987). The empathy–altruism claim remains contested, precisely because every demonstration must rule out a newly proposed egoistic alternative, but it is the most sustained case that human helping is not always, at bottom, self-interested. Demo 2 reconstructs Batson's two-by-two logic, letting the reader set empathy high or low and escape easy or difficult and see the predicted helping rate.

Egoistic Accounts: Arousal and Negative-State Relief

Against the altruistic reading stands a family of egoistic accounts, each proposing a self-directed goal that helping serves. The arousal: cost–reward model, developed from the Piliavin subway studies, holds that witnessing another's distress is physiologically arousing and unpleasant, and that the bystander acts to reduce that arousal, choosing the response—direct help, indirect help, or leaving—that does so most cheaply given the costs of helping and the costs of the victim receiving no help (Piliavin et al., 1969). Robert Cialdini's negative-state relief model sharpened the mechanism: a person made sad, whether by another's plight or by any other cause, is motivated to repair their mood, and helping is one reliable mood-repair device, so empathy promotes helping only because it produces sadness that helping then relieves (Cialdini et al., 1987).

Cialdini's experiments made the competing predictions testable. If helping under empathy is really mood-repair, then giving the empathic helper an alternative source of good mood—unexpected praise, money, or a mood-fixing drug they believe freezes their feelings—should remove the motivation to help; Cialdini reported exactly this attenuation, which Batson in turn contested on methodological grounds. The dispute was never cleanly resolved, and its real lesson is methodological: because almost any altruistic-looking act carries some incidental benefit to the helper, deciding between altruism and egoism requires experiments built specifically to pit one against the other, not mere observation that people help. Demo 3 lets the reader explore the arousal: cost–reward calculus, setting the cost of helping and the cost to the victim of no help and reading off the predicted response.

Evolutionary and Economic Roots

Helping non-relatives at a cost to oneself poses a problem for any account built on self-interest, biological or economic, and the resolution lies in reciprocity. Ernst Fehr and Urs Fischbacher argued that human cooperation extends far beyond kin and simple reciprocal exchange because humans are strong reciprocators: they reward cooperation and punish defection even when doing so is personally costly and yields no future return, a disposition that stabilises large-scale cooperation by making free-riding expensive (Fehr & Fischbacher, 2003). On this view a readiness to help, and to sanction those who do not, is part of an evolved and culturally elaborated system rather than a simple calculation of individual advantage.

Louis Penner and colleagues drew these strands into a multilevel framework, arguing that prosocial behavior must be analysed at three levels at once: the micro (the origins and development of prosocial tendencies in individuals), the meso (helper–recipient encounters, as in the bystander studies), and the macro (prosocial behavior in groups and organisations) (Penner et al., 2005). The framework is useful because it locates the situational, motivational, and evolutionary perspectives as answers to questions at different levels rather than as rivals: the bystander effect lives at the meso level, empathy–altruism at the micro, and strong reciprocity at the macro, and a complete account of a single helpful act may draw on all three.

Development and Individual Differences

If helping were purely a product of socialisation and self-interested calculation, it should appear late and vary wildly; in fact it appears strikingly early. Felix Warneken and Michael Tomasello showed that infants as young as 14 to 18 months spontaneously help an unfamiliar adult achieve a goal—retrieving an out-of-reach object, opening a cabinet whose owner's hands are full—without reward or encouragement, and that young chimpanzees perform some of the same instrumental helping, suggesting shared evolutionary roots (Warneken & Tomasello, 2006). Warneken later argued that this early helping is precocious and not initially driven by expectations of reciprocity or social approval, which emerge to shape and channel it only over subsequent years (Warneken, 2015).

Across individuals, helping is not evenly distributed, and the differences are partly dispositional. Alice Eagly and Maureen Crowley's meta-analysis of gender and helping found not that one sex helps more overall but that the kind of helping differs: men helped more in the chivalrous, heroic, and risky situations that dominated the experimental literature—brief encounters with strangers, often with onlookers—while the nurturant, sustained helping more common among women was largely absent from those studies, a reminder that measured sex differences can be artefacts of which helping gets studied (Eagly & Crowley, 1986). More recent work has related helping to stable personality, a thread the next section develops.

Worked Example

The mechanisms become concrete in three small exercises, each matching one of the demonstrations. The numbers below are illustrative—they capture the qualitative shape of the published findings rather than reproducing any single reported statistic.

Diffusion of responsibility (individual and group). Suppose a lone bystander would help with probability p​_alone = 0.85. Model diffusion by dividing that tendency as onlookers are added: with n bystanders, each individual's probability is p​_ind = p​_alone / (1 + k(n − 1)), where k = 0.6 sets the strength of diffusion. With n = 1 the individual probability is 0.85. With n = 5 it falls to 0.85 / (1 + 0.6 × 4) = 0.85 / 3.4 = 0.25. The probability that at least one of the five helps is 1 − (1 − 0.25)⁵ = 1 − 0.75⁵ = 1 − 0.237 = 0.76—lower than the 0.85 a single committed bystander would have provided. The group both dilutes each person's duty and, counter-intuitively, can leave the victim worse off than a lone witness would. Demo 1 lets the reader move n and k and watch both probabilities change.

Empathy–altruism (the two-by-two). Represent helping as a rate from 0 to 1 in Batson's design. Under low empathy, helping is egoistic and tracks escape: with easy escape the rate is low, say 0.18, because leaving relieves the arousal as cheaply as helping; with difficult escape it rises to 0.64, because now helping is the cheapest relief. Under high empathy the goal is the victim's welfare, so escape is irrelevant: the rate is high under both easy escape (0.83) and difficult escape (0.82). The diagnostic contrast is the easy-escape column: 0.18 under low empathy versus 0.83 under high—a gap of 0.65 that no purely egoistic account predicts. Demo 2 lets the reader toggle empathy and escape and read off the cell.

Arousal: cost–reward (a net impulse). Model the impulse to intervene directly as the cost to the victim of receiving no help minus the cost to the bystander of helping: I = C​_no-help − C​_help, each on a 0–10 scale. A clear, cheap-to-help emergency—C​_no-help = 9, C​_help = 2—gives I = +7, a strong pull toward direct intervention. A costly, ambiguous one—C​_no-help = 4, C​_help = 8—gives I = −4, predicting the bystander leaves, looks away, or redefines the event as not an emergency. The model's content is in the two costs: raising the cost of helping or lowering the victim's apparent need both push the same bystander from intervention toward escape. Demo 3 lets the reader set both costs and watch the predicted response shift.

Discussion

Read across its perspectives, the science of helping tells a coherent story about a behavior that is common, consequential, and more conditional than it feels from the inside. The situational perspective established that helping is powerfully shaped by the moment—above all by the presence of others, which dilutes responsibility and muddies the interpretation of events—so that failures to help are often failures of the situation rather than of character (Darley & Latané, 1968; Piliavin et al., 1969). The motivational perspectives then divided over why people help when they do: the empathy–altruism hypothesis holds that empathic concern can make another's welfare an end in itself, while egoistic accounts—arousal reduction, negative-state relief—insist the ultimate goal is always some benefit to the self (Batson et al., 1981; Cialdini et al., 1987; Eisenberg & Miller, 1987).

That debate has no clean victor, and its endurance is instructive: because almost any helpful act brings the helper some incidental benefit, altruism and egoism can be separated only by experiments built to pit them against each other, never by observing helping alone. The evolutionary and developmental perspectives reframe the question by widening the frame: helping of non-kin is stabilised by reciprocity and the costly punishment of free-riders, and its rudiments appear in infancy and in other apes, which suggests that a disposition to help is part of the human endowment rather than a thin cultural veneer (Fehr & Fischbacher, 2003; Warneken & Tomasello, 2006; Penner et al., 2005). The honest summary is that helping is neither simply selfish nor simply selfless, and neither a fixed trait nor a pure product of circumstance, but a behavior with situational triggers, mixed motives, deep roots, and real individual variation.

Current Directions

The most active front treats prosociality as structured rather than unitary, asking not whether a person is helpful but in what way and from what motive. Anne Böckler and colleagues distinguished altruistically motivated, norm-motivated, and strategically motivated prosocial behavior and showed that these come apart empirically—that self-reported prosociality predicts behaviour only weakly, and that the different motives have different correlates—so that lumping all helping together obscures more than it reveals (Böckler et al., 2016). A second front puts dispositional differences on a firm meta-analytic footing: Isabel Thielmann and colleagues synthesised hundreds of studies relating basic personality traits to prosocial behavior and found the most consistent predictors to be traits capturing other-regard and the willingness to bear personal cost for others, with the strength of the relation depending systematically on features of the situation (Thielmann et al., 2020). A third reframes the costs and benefits of helping for the helper, arguing that genuinely other-focused (“otherish”) motivation can serve the helper's own long-run well-being better than either pure self-interest or pure self-sacrifice (Crocker et al., 2017). Running through all three is a move to connect helping to emotion regulation: Jamil Zaki has argued that empathy is better understood as a set of partly controllable, motivated processes than as an automatic reflex, which reopens the question of when and how people choose to feel for—and help—others (Zaki, 2020).

Common Misconceptions

The bystander effect means people in cities are callous.

The effect is situational, not dispositional. The same person is less likely to help as the number of other onlookers grows, because responsibility diffuses and the event is harder to read, not because crowds are composed of uncaring individuals (Darley & Latané, 1968).

A larger crowd always means a victim is less likely to get any help at all.

What falls reliably is each individual's probability of intervening. Whether the probability that someone helps also falls depends on the numbers; in fast, unambiguous, face-to-face emergencies help can be frequent even in groups (Piliavin et al., 1969).

All helping is secretly selfish.

This may be true, but it cannot be established by noting that helpers feel good; that observation is equally consistent with altruism. The empathy–altruism hypothesis marshals experiments designed to rule out egoistic alternatives, and the question remains genuinely open rather than settled in egoism's favour (Batson et al., 1981).

Children must be taught to help; it does not come naturally.

Instrumental helping appears spontaneously in infants in the second year of life, before sustained socialisation for it and without reward, and some of it is shared with young chimpanzees—evidence that the disposition is early and partly built-in, however much culture later shapes it (Warneken & Tomasello, 2006).

Glossary

Altruism.

Helping motivated by the goal of benefiting another as an end in itself, rather than by any benefit to the self; a motivational claim about why helping occurs, not a kind of act.

Arousal: cost–reward model.

The egoistic account on which witnessing distress is aversively arousing, and the bystander chooses the response that reduces that arousal most cheaply, given the costs of helping and of the victim going unhelped.

Bystander effect.

The finding that an individual is less likely to help, and slower to do so, as the number of other bystanders present increases.

Diffusion of responsibility.

The process by which the obligation to act is shared among all present, so that each bystander feels less personal responsibility to intervene as the group grows; the primary mechanism of the bystander effect.

Egoistic motivation.

Motivation to help whose ultimate goal is a benefit to the self—relief of distress, mood repair, reward, or avoided censure—even when the act benefits another.

Empathic concern.

An other-oriented emotional response of sympathy and compassion for a person in need, distinguished from the self-oriented personal distress their plight may also cause; the proposed source of altruistic motivation.

Empathy–altruism hypothesis.

Batson's claim that empathic concern for another evokes motivation with the other's welfare as its ultimate goal, not reducible to any egoistic motive.

Helping behavior.

Voluntary action undertaken to benefit another person; the subject of this article and a MeSH descriptor filed under social behavior, irrespective of the helper's underlying motive.

Instrumental helping.

Helping another achieve an action goal they cannot complete alone—retrieving an out-of-reach object, opening a door—the earliest form of helping to emerge in human infants and the form shared with chimpanzees.

Negative-state relief.

Cialdini's egoistic model on which a person in a sad or negative mood helps because helping reliably repairs mood, so empathy promotes helping only via the sadness it induces.

Pluralistic ignorance.

The shared misreading of a situation that occurs when each bystander, seeing the others remain outwardly calm, concludes that nothing is wrong—suppressing intervention at the interpretation step.

Prosocial behavior.

The broad category of voluntary acts intended to benefit others—helping, sharing, comforting, cooperating, donating—of which helping behavior is the central case.

Reciprocal altruism.

Helping another in the expectation of a returned benefit later; one evolutionary route by which a costly disposition to help non-kin can be sustained.

Social behavior.

Action directed at or shaped by other members of one's species; the MeSH parent category under which helping is filed, since it is defined by its orientation toward another party.

Strong reciprocity.

The disposition to reward cooperation and punish defection even at personal cost and with no prospect of future return; a mechanism Fehr and Fischbacher proposed to explain large-scale human cooperation among non-kin.

Key Researchers

C. Daniel Batson

(Professor Emeritus of Social Psychology, University of Kansas). Originated the empathy–altruism hypothesis and the experimental programme designed to show that empathic concern can motivate genuinely other-oriented helping. Wikipedia · Faculty Page

Robert B. Cialdini

(Regents' Professor Emeritus of Psychology and Marketing, Arizona State University). Proposed the negative-state relief model, the leading egoistic account of empathy-based helping as a means of repairing the helper's own mood. Wikipedia · Faculty Page

John M. Darley

(1938–2018) (Princeton University). Co-discoverer, with Bibb Latané, of the bystander effect and diffusion of responsibility, and author of the five-step model of intervention. Wikipedia · In Memoriam

Nancy Eisenberg

(Regents' Professor Emerita of Psychology, Arizona State University). A leading authority on empathy, sympathy, and the development of prosocial and moral behavior across the lifespan. Google Scholar · Wikipedia · Faculty Page

Bibb Latané

(Center for Human Science, Chapel Hill). Co-discoverer of the bystander effect and diffusion of responsibility, and originator of social impact theory. Wikipedia · Faculty Page

Michael Tomasello

(James F. Bonk Distinguished Professor of Psychology and Neuroscience, Duke University). Studies the comparative and developmental origins of cooperation and shared intentionality in children and apes, including the early emergence of helping. Google Scholar · Wikipedia · Faculty Page

Felix Warneken

(Department of Psychology, University of Michigan). Established that instrumental helping emerges spontaneously in human infants and young chimpanzees, founding the modern developmental study of altruism. ORCID · Google Scholar · Faculty Page

Frequently Asked Questions

What is helping behavior in psychology?

Helping behavior is voluntary action undertaken to benefit another person, from aiding a stranger in an emergency to assisting a familiar other with a task. It is the central case of prosocial behavior and is studied through two questions: when people help, and why (Penner et al., 2005).

What is the bystander effect?

It is the finding that a person is less likely to help, and slower to act, as the number of other onlookers increases. The main mechanisms are diffusion of responsibility—the sense of obligation is shared among all present—and pluralistic ignorance, the shared misreading of a calm-looking crowd as evidence that nothing is wrong (Darley & Latané, 1968).

What is diffusion of responsibility?

It is the reduction in each individual's felt responsibility to act when responsibility is shared among many bystanders. A lone witness bears the whole obligation to help; one of many bears only a fraction, which is why larger groups intervene less reliably per person (Darley & Latané, 1968).

What is the empathy–altruism hypothesis?

It is Daniel Batson's claim that feeling empathic concern for a person in need evokes motivation whose ultimate goal is that person's welfare, rather than any benefit to oneself. It is supported by experiments in which high-empathy participants help even when they could easily escape the situation (Batson et al., 1981).

Is helping ever truly selfless, or always selfish?

The question is genuinely open. Egoistic accounts such as negative-state relief explain helping as mood repair or arousal reduction, while the empathy–altruism hypothesis argues that empathic concern produces genuinely other-oriented motivation. Because helpers almost always gain some incidental benefit, only experiments designed to pit the two against each other can decide between them (Cialdini et al., 1987; Batson et al., 1981).

When do children start to help?

Strikingly early. Infants of 14 to 18 months spontaneously help an unfamiliar adult reach a goal—retrieving a dropped object, opening a cabinet—without reward or prompting, and young chimpanzees show some of the same instrumental helping, which suggests the disposition is early and partly built-in (Warneken & Tomasello, 2006).

Do men or women help more?

Neither helps more overall; the kind of helping differs. A meta-analysis found men helped more in the brief, risky, chivalrous encounters that dominated the experimental literature, while the sustained, nurturant helping more common among women was largely unstudied—so apparent sex differences partly reflect which helping researchers measured (Eagly & Crowley, 1986).

How does personality relate to helping?

Stable traits predict prosocial behavior, and the most consistent predictors are those capturing concern for others and a willingness to bear personal cost for them. A large meta-analysis found these relations are real but depend systematically on the situation, so disposition and circumstance jointly determine who helps (Thielmann et al., 2020).

References

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Böckler, A., Tusche, A., & Singer, T. (2016). The structure of human prosociality: Differentiating altruistically motivated, norm motivated, strategically motivated, and self-reported prosocial behavior. Social Psychological and Personality Science, 7(6), 530–541. https://doi.org/10.1177/1948550616639650

Cialdini, R. B., Schaller, M., Houlihan, D., Arps, K., Fultz, J., & Beaman, A. L. (1987). Empathy-based helping: Is it selflessly or selfishly motivated? Journal of Personality and Social Psychology, 52(4), 749–758. https://doi.org/10.1037/0022-3514.52.4.749

Crocker, J., Canevello, A., & Brown, A. A. (2017). Social motivation: Costs and benefits of selfishness and otherishness. Annual Review of Psychology, 68, 299–325. https://doi.org/10.1146/annurev-psych-010416-044145

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Eagly, A. H., & Crowley, M. (1986). Gender and helping behavior: A meta-analytic review of the social psychological literature. Psychological Bulletin, 100(3), 283–308. https://doi.org/10.1037/0033-2909.100.3.283

Eisenberg, N., & Miller, P. A. (1987). The relation of empathy to prosocial and related behaviors. Psychological Bulletin, 101(1), 91–119. https://doi.org/10.1037/0033-2909.101.1.91

Fehr, E., & Fischbacher, U. (2003). The nature of human altruism. Nature, 425(6960), 785–791. https://doi.org/10.1038/nature02043

Penner, L. A., Dovidio, J. F., Piliavin, J. A., & Schroeder, D. A. (2005). Prosocial behavior: Multilevel perspectives. Annual Review of Psychology, 56, 365–392. https://doi.org/10.1146/annurev.psych.56.091103.070141

Piliavin, I. M., Rodin, J., & Piliavin, J. A. (1969). Good Samaritanism: An underground phenomenon? Journal of Personality and Social Psychology, 13(4), 289–299. https://doi.org/10.1037/h0028433

Schroeder, D. A., & Graziano, W. G. (Eds.). (2015). The Oxford handbook of prosocial behavior. Oxford University Press. https://doi.org/10.1093/oxfordhb/9780195399813.001.0001

Thielmann, I., Spadaro, G., & Balliet, D. (2020). Personality and prosocial behavior: A theoretical framework and meta-analysis. Psychological Bulletin, 146(1), 30–90. https://doi.org/10.1037/bul0000217

Warneken, F., & Tomasello, M. (2006). Altruistic helping in human infants and young chimpanzees. Science, 311(5765), 1301–1303. https://doi.org/10.1126/science.1121448

Warneken, F. (2015). Precocious prosociality: Why do young children help? Child Development Perspectives, 9(1), 1–6. https://doi.org/10.1111/cdep.12101

Zaki, J. (2020). Integrating empathy and interpersonal emotion regulation. Annual Review of Psychology, 71, 517–540. https://doi.org/10.1146/annurev-psych-010419-050830