Jean-Baptiste André

• Researcher at CNRS - Ecole Normale Supérieure de Paris

Why do humans believe in moralizing gods? Leading accounts argue that these beliefs evolved because they help societies grow and promote group cooperation. Yet recent evidence suggests that beliefs in moralizing gods are not limited to large societies and might not have strong effects on cooperation. Here, we propose that beliefs in moralizing gods...

Institutions allow cooperation to persist when reciprocity and reputation provide insufficient incentives. Yet how they do so remains unclear, especially given that institutions are themselves a form of cooperation. To solve this puzzle, we develop a mathematical model of reputation-based cooperation in which two social dilemmas are nested within o...

Interpersonal trust impacts societal and individual outcomes, affecting economic growth, democracy, and well-being. Trust levels vary both within and across countries, raising the question of what factors influence interpersonal trust. Existing research indicates that an individual’s socioeconomic status influences their level of trust, with wealth...

Human moral judgments are both precise, with clear intuitions about right and wrong, and at the same time obscure, as they seem to result from principles whose logic often escapes us. The development of Artificial Intelligence (AI) applications requires an understanding of this subtle logic if we are to embed moral considerations in artificial syst...

What role do emotions play in moral cognition? Leading accounts argue that a multiplicity of emotions, including guilt, outrage, shame, empathy, and even disgust, play an essential role in moral psychology. Here, this chapter argues that many of these emotions are only super cially associated with moral cognitive contents and adaptive challenges, a...

Individuals living in either harsh or favorable environments display well-documented psychological and behavioral differences. For example, people in favorable environments tend to be more future-oriented, trust strangers more, and have more explorative preferences. To account for such differences, psychologists have turned to evolutionary biology...

While necessary parts of the puzzle, cultural technologies are insufficient to explain peace. They are a form of second-order cooperation - a cooperative interaction designed to incentivize first-order cooperation. We propose an explanation for peacemaking cultural technologies, and therefore peace, based on the reputational incentives for second-o...

We applaud Boyer's attempt to ground the psychology of ownership partly in a cooperative logic. In this commentary, we propose to go further and ground the psychology of ownership solely in a cooperative logic. The predictions of bargaining theory, we argue, completely contradict the actual features of ownership intuitions. Ownership is only about...

Commentators raise fundamental questions about the notion of purity (sect. R1), the architecture of moral cognition (sect. R2), the functional relationship between morality and cooperation (sect. R3), the role of folk-theories of self-control in moral judgment (sect. R4), and the cultural variation of morality (sect. R5). In our response, we addres...

Addressing global environmental crises such as anthropogenic climate change requires the consistent adoption of proenvironmental behavior by a large part of a population. Here, we develop a mathematical model of a simple behavior-environment feedback loop to ask how the individual assessment of the environmental state combines with social interacti...

Standard approaches to cultural evolution focus on the recipients or consumers. This does not take into account the fitness costs incurred in producing the behaviors or artifacts that become cultural, i.e., widespread in a social group. We argue that cultural evolution models should focus on these fitness costs and benefits of cultural production p...

What explains the ubiquity and cultural success of prosocial religions? Leading accounts argue that prosocial religions evolved because they help societies grow and promote group cooperation. Yet recent evidence suggests that prosocial religious beliefs are not limited to large societies and might not have strong effects on cooperation. Here, we pr...

Institutions explain humans’ exceptional levels of cooperation. Yet institutions are at the mercy of the very problem they are designed to solve. They are themselves cooperative enterprises, so to say that institutions stabilize cooperation just begs the question: what stabilizes institutions? Here, we use a mathematical model to show that reputati...

Many games, especially repeated games, have multiple Nash equilibria. This multiplicity limits the predictive power of game theory for understanding animal behavior, and plays an important role in evolutionary anthropology as a seemingly irrefutable argument that cultural group selection is necessary for human cooperation. In this article, I propos...

People make many inferences based on cues of wealth. These inferences regarding the character and behavior of others have real-life consequences, for example, social distancing from individuals at the lower end of the socio-economic spectrum. In this cross-cultural study, we investigate the association between perceived wealth and perceived trustwo...

We use an evolutionary approach to explain the existence and design features of human moral cognition. Because humans are under selection to appear as good cooperative investments, they face a trade-off between maximizing the immediate gains of each social interaction and maximizing its long-term reputational benefits. In a simplified game, we show...

Commentators raise fundamental questions about the notion of purity (sect. R1), the architecture of moral cognition (sect. R2), the functional relationship between morality and cooperation (sect. R3), the role of folk-theories of self-control in moral judgement (sect. R4), and the cultural variation of morality (sect. R5). In our response, we addre...

Studies have shown that people hold a number of stereotypes associated with wealth, wherein individuals of higher socio-economic status are often perceived as more competent, yet less warm. These wealth-based stereotypes can be activated by a diverse range of cues, such as clothing, accents, food preferences or facial expressions. The effects of th...

This section exposes twenty-five key concepts in evolutionary biology and in economics. Each concept is explicated first in evolutionary biology, then in economics. Then, a short synthesis presents some differences and some commonalities.

Why do many societies moralize apparently harmless pleasures, such as lust, gluttony, alcohol, drugs, and even music and dance? Why do they erect temperance, asceticism, sobriety, modesty, and piety as cardinal moral virtues? According to existing theories, this puritanical morality cannot be reduced to concerns for harm and fairness: it must emerg...

Addressing global environmental crises such as climate change requires the adoption of consistent proenvironmental behaviour by a large part of a population. Identifying the main determinants of proenvironmental behavioural consistency remains challenging. Here, we ask how the individual assessment of environmental actions interacts with social nor...

Life history theory is increasingly invoked in psychology as a framework for understanding differences in individual preferences. In particular, evolutionary human scientists tend to assume that, along with reproductive strategies, several behavioral traits such as cooperation and risk-taking and, in its broadest version, a range of psychological a...

Our goal in this paper is to use an evolutionary approach to explain the existence and design-features of human moral cognition. Our approach is based on the premise that human beings are under selection to appear as good cooperative investments. Hence they face a trade-off between maximizing the immediate gains of each social interaction, and maxi...

Many evolutionary models explain why we cooperate with non-kin, but few explain why cooperative behaviour and trust vary. Here, we introduce a model of cooperation as a signal of time preferences, which addresses this variability. At equilibrium in our model (i) future-oriented individuals are more motivated to cooperate, (ii) future-oriented popul...

This paper focuses on a class of reinforcement learning problems where significant events are rare and limited to a single positive reward per episode. A typical example is that of an agent who has to choose a partner to cooperate with, while a large number of partners are simply not interested in cooperating, regardless of what the agent has to of...

In recent decades, a large body of work has highlighted the importance of emotional processes in moral cognition. Since then, a heterogeneous bundle of emotions as varied as anger, guilt, shame, contempt, empathy, gratitude, and disgust have been proposed to play an essential role in moral psychology. However, the inclusion of these emotions in the...

We propose an approach reconciling the ultimate-level explanations proposed by Savage et al. and Mehr et al. as to why music evolved. We also question the current adaptationist view of culture, which too often fails to disentangle distinct fitness benefits.

Individual observations of risky behaviors present a paradox: individuals who take the most risks in terms of hazards (smoking, speeding, risky sexual behaviors) are also less likely to take risks when it comes to innovation, financial risks or entrepreneurship. Existing theories of risk-preferences do not explain these patterns. From a simple mode...

Many evolutionary models explain why we cooperate with non kin, but few explain why cooperative behavior and trust vary. Here, we introduce a model of cooperation as a signal of time preferences, which addresses this variability. At equilibrium in our model, (i) future-oriented individuals are more motivated to cooperate, (ii) future-oriented popul...

Why do many human societies condemn apparently harmless and pleasurable behaviors, such as lust, gluttony, drinking, drugs, gambling, or even music and dance? Why do they erect temperance, hedonic restraint, sobriety, decency and piety as cardinal moral virtues? While existing accounts consider this puritanical morality as an exception to the coope...

The effects of partner choice have been documented in a large number of biological systems such as sexual markets, interspecific mutualisms, or human cooperation. There are, however, a number of situations in which one would expect this mechanism to play a role, but where no such effect has ever been demonstrated. This is the case in particular in...

In principle, any cooperative behaviour can be evolutionarily stable as long as it is incentivized by a reward from the beneficiary, a mechanism that has been called reciprocal cooperation. However, what makes this mechanism so powerful also has an evolutionary downside. Reciprocal cooperation faces a chicken-and-egg problem of the same kind as com...

In recent decades, a large body of work has highlighted the importance of emotional processes in moral cognition. Since then, a heterogeneous bundle of emotions as varied as anger, guilt, shame, contempt, empathy, gratitude, and disgust have been proposed to play an essential role in moral psychology. However, the inclusion of these emotions in the...

This paper focuses on a class of reinforcement learning problems where significant events are rare and limited to a single positive reward per episode. A typical example is that of an agent who has to choose a partner to cooperate with, while a large number of partners are simply not interested in cooperating, regardless of what the agent has to of...

Individuals exposed to deprivation tend to show a characteristic behavioral syndrome suggestive of a short time horizon. This pattern has traditionally been attributed to the intrinsically higher unpredictability of deprived environments, which renders waiting for long term rewards more risky (i.e. collection risks are high). In the current paper,...

[This corrects the article DOI: 10.1371/journal.pone.0236715.].

Why do, across ascetic spiritual traditions (e.g. Ancient Greek spiritualities, Stoicism, Christianity, Buddhism, Jainism, Hinduism, Confucianism), a moralizing side restricting bodily pleasures, and a joyful side celebrating self-control derived well-being develop in concert? Why are these two intertwined cultural traits a recent development in hu...

In principle, any cooperative behaviour can be evolutionarily stable as long as it is incentivized by a reward from the beneficiary, a mechanism that has been called reciprocal cooperation. However, what makes this mechanism so powerful also has an evolutionary downside. Reciprocal cooperation faces a chicken-and-egg problem of the same kind as com...

Why do, across ascetic spiritual traditions (e.g. Ancient Greek spiritualities, Stoicism, Christianity, Buddhism, Jainism, Hinduism, Confucianism), a moralizing side restricting bodily pleasures, and a joyful side celebrating self-control derived well-being develop in concert? Why are these two intertwined cultural traits a recent development in hu...

Individual observations of risky behaviors present a paradox: individuals who take the most risks in terms of hazards (smoking, speeding, risky sexual behaviors) are also less likely to take risks when it comes to innovation, financial risks or entrepreneurship. Existing theories of risk-preferences do not explain these patterns. From a simple mode...

Environmental adversity is associated with a wide range of biological outcomes and behaviors that seem to fulfill a need to favor immediate over long-term benefits. Adversity is also associated with decreased investment in cooperation, which is defined as a long-term strategy. Beyond establishing the correlation between adversity and cooperation, t...

In contrast to language or technology, many “symbolic” cultural phenomena do not seem to confer immediate fitness benefits. Standard approaches to cultural evolution in this domain focus on the recipients or consumers, which does not explain why these phenomena emerge. As a solution, we propose to consider the fitness costs and benefits incurred in...

In this article, we model cultural knowledge as a capital in which individuals invest at a cost. To this end, following other models of cultural evolution, we explicitly consider the investments made by individuals in culture as life history decisions. Our aim is to understand what then determines the dynamics of cultural accumulation. We show that...

The effects of partner choice have been documented in a large number of biological systems such as sexual markets, inter-specific mutualisms, or human cooperation. By contrast, this mechanism has never been demonstrated in a large number of intra-specific interactions in non-human animals such as collective hunts, although one would expect it to pl...

Social interactions involving coordination between individuals are subject to an “evolutionary trap.” Once a suboptimal strategy has evolved, mutants playing an alternative strategy are counterselected because they fail to coordinate with the majority. This creates a detrimental situation from which evolution cannot escape, preventing the evolution...

It is commonly asserted that when extrinsic mortality is high, individuals should invest early in reproduction. This intuition thrives in the literature on life-history theory and human behavior, yet it has been criticized repeatedly on the basis of mathematical models. The intuition is indeed wrong; but a recent theoretical criticism has confused...

Individuals exposed to deprivation tend to show a characteristic behavioural syndrome suggestive of a short time horizon. This pattern has traditionally been attributed to the intrinsically higher unpredictability of deprived environments, which renders waiting for long term rewards more risky (i.e. collection risks are high). In the current paper,...

It is commonly asserted that when extrinsic mortality is high, individuals should invest early in reproduction. This intuition thrives in the literature on life-history theory and human behavior, yet it has been criticized repeatedly on the basis of mathematical models. The intuition is indeed wrong; but a recent theoretical criticism has confused...

This paper aims to understand the dynamics of cultural accumulation when cultural knowledge is costly to produce and costly to learn. We first show that the cost of social learning prevents any significant cultural accumulation, as individuals rapidly reach a maximum amount of knowledge that they can barely learn over the course of their lives, wit...

A growing number of experimental and theoretical studies show the importance of partner choice as a mechanism to promote the evolution of cooperation, especially in humans. In this paper, we focus on the question of the precise quantitative level of cooperation that should evolve under this mechanism. When individuals compete to be chosen by others...

A bstract A growing number of experimental and theoretical studies show the importance of partner choice as a mechanism to promote the evolution of cooperation, especially in humans. In this paper, we focus on the question of the precise quantitative level of cooperation that should evolve under this mechanism. When individuals compete to be chosen...

Evolutionary game theory shows that social interactions involving coordination between individuals are subject to an "evolutionary trap." Once a suboptimal strategy has evolved, mutants playing an alternative strategy are counterselected because they fail to coordinate with the majority. This creates a detrimental situation from which evolution can...

We applaud Boyer & Petersen's (B&P's) article on economic folk beliefs. We believe that it is crucial for the future of democracy to identify the cognitive systems through which people form their beliefs about the working of the economy. In this commentary, we put forward the idea that, although many systems are involved, fairness is probably the m...

In biology, natural selection is the main explanation of adaptations and it is an attractive idea to think that an analogous force could have the same role in cultural evolution. In support of this idea, all the main ingredients for natural selection have been documented in the cultural domain. However, the changes that occur during cultural transm...

Pepper & Nettle explain the behavioral constellation of deprivation (BCD) in terms of differences in collection risk (i.e., the probability of collecting a reward after some delay) between high- and low-socioeconomic-status (SES) populations. We argue that a proper explanation should also include the costs of waiting per se, which are paid even whe...

[This corrects the article DOI: 10.1371/journal.pone.0173636.].

Menopause, the permanent cessation of ovulation, occurs in humans well before the end of the expected lifespan, leading to an extensive post-reproductive period which remains a puzzle for evolutionary biologists. All human populations display this particularity; thus, it is difficult to empirically evaluate the conditions for its emergence. In this...

Equity, defined as reward according to contribution, is considered a central aspect of human fairness in both philosophical debates and scientific research. Despite large amounts of research on the evolutionary origins of fairness, the evolutionary rationale behind equity is still unknown. Here, we investigate how equity can be understood in the co...

Simulation procedures, analytical model and supplementary discussion. (PDF)

The relative rarity of reciprocity in nature, contrary to theoretical predictions that it should be widespread, is currently one of the major puzzles in social evolution theory. Here we use evolutionary robotics to solve this puzzle. We show that models based on game theory are misleading because they neglect the mechanics of behavior. In a series...

Equity, defined as reward according to contribution, is considered a central aspect of human fairness in both philosophical debates and scientific research. Despite large amounts of research on the evolutionary origins of fairness, the evolutionary rationale behind equity is still unknown. Here, we investigate how equity can be understood in the co...

Mutualistic cooperation often requires multiple individuals to behave in a coordinated fashion. Hence, while the evolutionary stability of mutualistic cooperation poses no particular theoretical difficulty, its evolutionary emergence faces a chicken and egg problem: an individual cannot benefit from cooperating unless other individuals already do s...

In the ultimatum game, two people need to agree on the division of a sum of money. People usually divide money equally for the sake of fairness, and prefer to suffer financial losses rather than accept unfair divisions, contradicting the predictions of orthodox game theory. Models aimed at accounting for the evolution of such irrational preferences...

Many studies demonstrate that partner choice has played an important role in the evolution of human cooperation, but little work has tested its impact on the evolution of human fairness. In experiments involving divisions of money, people become either over-generous or over-selfish when they are in competition to be chosen as cooperative partners....

Abstract Reciprocity is characterized by individuals actively making it beneficial for others to cooperate by responding to them. This makes it a particularly powerful generator of mutual interest, because the benefits accrued by an individual can be redistributed to another. However, reciprocity is a composite biological function, entailing at lea...

One of the hallmarks of human fairness is its insensitivity to power: while strong individuals are often in a position to coerce weak individuals, fairness requires them to share the benefits of cooperation equally. The existence of such egalitarianism is poorly explained by current evolutionary models. We present a model based on cooperation and p...

Social evolution theory faces a puzzle: a gap between theoretical and empirical results on reciprocity. On the one hand, models show that reciprocity should evolve easily in a wide range of circumstances. On the other hand, empirically, few clear instances of reciprocity (even in a broad sense) have been found in nonhuman animals. In this paper, I...

Transmitted culture can be viewed as an inheritance system somewhat independent of genes that is subject to processes of descent with modification in its own right. Although many authors have conceptualized cultural change as a Darwinian process, there is no generally agreed formal framework for defining key concepts such as natural selection, fitn...

What makes humans moral beings? This question can be understood either as a proximate “how” question or as an ultimate “why” question. The “how” question is about the mental and social mechanisms that produce moral judgments and interactions, and has been investigated by psychologists and social scientists. The “why” question is about the fitness c...

Our discussion of the commentaries begins, at the evolutionary level, with issues raised by our account of the evolution of morality in terms of partner-choice mutualism. We then turn to the cognitive level and the characterization and workings of fairness. In a final section, we discuss the degree to which our fairness-based approach to morality e...

The evolutionary foundations of helping among nonkin in humans have been the object of intense debates in the past decades. One thesis has had a prominent influence in this debate: the suggestion that genuine altruism, strictly defined as a form of help that comes at a net fitness cost for the benefactor, might have evolved owing to cultural transm...

We model the evolution of the division of a resource between two individuals, according to a bargaining mechanism akin to the ultimatum game, in which a dominant proposer makes an offer that his partner can only accept or refuse. Individuals are randomly drawn from an infinite population and paired two-by-two. In each pair, a proposer is chosen. Th...

Human beings universally express a concern for the fairness of social interactions, and it remains an open question that which ultimate factors led to the evolution of this preference. Here, we present a model accounting for the evolution of fairness on the basis of individual selection alone. We consider a simple social interaction based on the Di...

Modes of cultural transmission are, by analogy with modes of genetic transmission, ways in which cultural information is transmitted between individuals. Despite its importance across the behavioral sciences and for theories of cultural evolution, no attempts have been made, to our knowledge, to critically analyze this analogy. We here aim at such...

Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. Nowak et al. argue that inclusive fitness theory has been of little value in explaining the natural world, and that it has led to negligible progress in explaining the evolution of eusociality. However, we believe that their arguments are based upon a...

The vast majority of human beings regularly engage in reciprocal cooperation with nonrelated conspecifics, and yet the current evolutionary understanding of these behaviors is insufficient. Intuitively, reciprocity should evolve if past behavior conveys information about future behavior. But it is not straightforward to understand why this should b...