[This corrects the article DOI: 10.1371/journal.pone.0344731.].

The human pointing gesture is a species-unique and species-universal form of communication that depends on humans' especially powerful forms of cooperative cognition and motivation. I have previously hypothesized that the pointing gesture evolved as a behavioral tool empowering individuals to better coordinate their interdependent collaborative activities by informing one another of things helpfully. Here I provide new data in support of this hypothesis, focusing on the different ways in which human children and nonhuman great apes communicate to initiate, coordinate, and self-regulate their collaborative activities. All great apes collaborate and communicate, but humans collaborate and communicate in coordinated ways.

Early in ontogeny, children show a preference for prosocial others and for those with helpful intentions. Here, we investigate how children reason about prosocial actions when a selfish intention is revealed only after a prosocial behavior has benefitted them. 5-year-old children (N = 48) played a game with a puppet who acted prosocially by letting the child take a turn in a game. After the game, the puppet revealed either a selfish intention of getting a cookie for letting the child play (Undermining condition) or a prosocial intention of wanting the child to have fun (Prosocial condition). When given a chance to reciprocate a prosocial act, children shared less when the puppet had an Undermining versus a Prosocial intention. Children did not show any condition differences in their explicit social evaluations of the puppet, however. Our results indicate that an agent's initially hidden selfish intention, revealed only after a prosocial action, negatively impacts a child's willingness to later reciprocate with that agent.

Much research has examined young children's (lack of) understanding of the subjectivity of beliefs, yet the other side of the issue has remained overlooked: Do young children understand the objectivity of reality? In this study, 83 children from 4 to 5 years of age completed: (i) the False Belief Task, which assessed children's understanding that a character's subjective beliefs may not correspond to an altered objective reality and (ii) a novel Objective Reality Task, which assessed children's understanding that the objective reality may not correspond to a character's altered subjective beliefs. Performances on the two tasks improved in similar trajectories from 4 to 5 years of age and were correlated, including when controlling for age, suggesting similar underlying developmental processes. These findings provide empirical support for the analytical supposition that subjectivity and objectivity are complementary forms of understanding.

Three experiments investigated whether reciprocity in children aged 4-7 (N = 192; 53.12% female; 65.63% White) is sensitive to the cost of a gift from the benefactor's perspective. In the main study, 6- and 7-year-olds, but not 4- and 5-year-olds, preferred to reward a benefactor who valued a gift highly over one who gave an identical gift but valued it less. A follow up study found that 5- but not 4-year-olds at least expected object valuation to impact sharing. In the third study, 6- and 7-year-olds even rewarded a benefactor whose gift they themselves (the children) valued less (than another's gift) if that benefactor herself had valued it highly. Increasingly over age, young children's sharing and reciprocity consider subjective costs.

Even young toddlers coordinate actions with a partner. But coordinating choices or decisions is more challenging, particularly in multi-party groups. In this pre-registered study (data collected from Fall 2023 to Spring 2025), 2- and 3-year-olds (n = 100, 50% female, 26% underrepresented minority) needed to select "keys" that matched in color to open a box. Children coordinated with one another in same-aged dyads or triads. In dyads, children of both ages were mostly successful, whereas 3-year-olds were much more successful than 2-year-olds in triads. This was especially true in a generalization trial in which only one of ten 2-year-old triads was successful, while all other groups were successful. Success at both ages was predicted by rates of cooperative communication about their choice of key. These results demonstrate that even 2-year-olds can coordinate choices with a single partner, but doing so in groups tends to emerge at around age three, when children begin to develop more advanced ways of thinking about and working with others.

Abstract The study of great ape cognition offers insights into the evolutionary origins of human intelligence, but is hindered by small sample sizes and restricted access to data. To address this, we present the EVApeCognition Dataset, a publicly available resource comprising 262 experimental datasets from 150 scientific publications from the Wolfgang Köhler Primate Research Center (2004–2021) in Leipzig, Germany. Eighty-one apes participated in 150 studies, with a majority (N = 78) participating in more than one study. Publication of the dataset aims to make these unique datasets accessible for future meta-analyses and correlational analyses, helping us better understand how our great ape relatives think, learn, and behave.

Within their peer cultures, children not only teach and socially learn from one another, but they also prompt one another to confront and adapt to different, coequal perspectives in a way that superintending adults cannot do.

Classic false-belief tasks may be confusing because children converse with someone who knows that a situation has changed about a third person who does not know this. Two studies used a collaborative false-belief task in which US- and UK-based 3-year-olds (N = 84, 48 girls, data collection: 2023) and a partner had to jointly decide in which box a toy was hidden. Children informed their partner and provided reasons about the location of the toy more when their partner had a false belief than when they had a true belief. We discuss the hypothesis that collaborative decision making pushes children to understand how their partner's perspective relates to their own and, when they differ, to assess how each corresponds to reality.

Nature cannot build organisms biologically prepared for every contingency they might possibly encounter. Instead, nature builds some organisms to function as feedback control systems that pursue goals, make informed behavioral decisions about how best to pursue those goals in the current situation, and then monitor behavioral execution for effectiveness. Nature builds psychological agents, and these are of several different types depending on the nature of the self-regulatory architecture involved. Humans have evolved to create joint and collective agencies with others, which has enabled them to construct the unique cultural niches within which all of their most complex cognitive and social capacities develop.

The quest to make artificial intelligence models more human-like could profit from a study of biological agents and their evolution. Recent research suggests that animal species on the evolutionary line to humans employed a series of qualitatively distinct agentive architectures of ever-increasing complexity, with humans then forming shared agencies coordinated via linguistic communication.

Although children are influenced by social norms from birth, they only begin to understand social norms as such in the three to five year age period. It is at this age that they begin to enforce conformity to social norms on others, even using the normative language of should, must, and ought to. By the end of this age period, they are even capable of creating new social norms (i.e., game rules) themselves, and they automatically see these as binding on everyone concerned, suggesting an understanding that the force of social norms comes not just from adult authority but also from agreement. Although particular social norms differ among cultures, it seems that children in all cultures are born with the same basic norm psychology.

Why have some organisms evolved processes of attention as distinct from perception in general? Investigation of freely behaving organisms (not in laboratory tasks) suggests that attention as distinct from perception is critical for goal-directed organisms' value-based decision making. As such, the target of attention is not punctate stimuli, but whole situations (scenes) that are relevant to that decision.

Para explicar a origem evolutiva de habilidades e motivações exclusivamente humanas para a cooperação, Tomasello et al. (2012) propuseram a hipótese da interdependência. O contexto adaptativo chave nesse relato foi o forrageamento colaborativo obrigatório de adultos humanos primitivos. Hawkes (2014), seguindo Hrdy (2009), forneceu um relato alternativo para o surgimento de habilidades cooperativas exclusivamente humanas em que a chave eram as tentativas dos primeiros bebês humanos de solicitar cuidado e atenção de adultos em um contexto de criação cooperativa. Aqui, tentamos reconciliar esses dois relatos. Nossa explicação composta aceita o argumento de Hrdy e Hawkes de que o surgimento extremamente precoce das habilidades cooperativas dos bebês humanos sugere um papel importante para a criação cooperativa como contexto adaptativo, talvez no Homo primitivo. Mas nossa proposta também insiste que a cooperação humana vai muito além dessas habilidades incipientes, para incluir coisas como convenções, normas e instituições comunicativas e culturais criadas por Homo posteriores e humanos modernos primitivos para lidar com problemas adultos de coordenação social. Como parte dessa proposta, levantamos a hipótese de como cada um dos principais estágios da ontogenia humana (primeira infância, segunda infância e adolescência) foi transformado durante a evolução tanto pela migração “para cima” na idade das habilidades cooperativas dos bebês, quanto pela migração “para baixo” das habilidades cooperativas dos adultos. Versão original: TOMASELLO, Michael; GONZALEZ-CABRERA, Ivan. The role of ontogeny in the evolution of human cooperation. Human nature, v. 28, n. 3, p. 274-288, 2017. Tradução: Beto Vianna Submissão: 15 mar. 2025 ⊶ Aceite: 11 jun. 2025

Three-year-old children normatively protest the transgression of adult rules in a variety of contexts. Five-year-olds also normatively protest the transgression of rules they have themselves created collaboratively with peers. But do children of these ages protest rules that they have created for themselves as individuals? We prompted five-year-olds (Study 1: 128 participants, 69 females) and three-year-olds (Study 2: 64 participants, 32 females) to devise a way to play with a toy in the presence of some puppet peers, after which a new puppet engaged with the toy the 'wrong' way. Results showed that five-year-olds protested at similar rates regardless of whether they came up with a way to play collaboratively with others and then played together (collaborative condition), came up with a way to play individually but then played together (two trendsetter conditions), or came up with a way to play and played totally individually (solo condition). In Study 2, three-year-olds protested self-created rules as well, albeit at lower rates than five-year-olds. Finally, neither age group's protest seemed to be influenced by instructions containing explicit cues of normativity or conventionality (e.g., creating a game with rules vs coming up with a way to play). As such, when children create norms themselves, their willingness to protest novice transgressors seems not to be impacted by the degree to which these norms were created through collaboration. Moreover, our results show that promiscuous normativity of self-created norms emerges earlier than previously thought, around the same time children become promiscuous normativists towards adult-created norms.

Linguists often characterize syntax in terms of combinatorial rules. But there is also a pragmatics to syntax in which communicators choose and tailor syntactic constructions for different communicative contexts. Great apes exposed to "language" combine elements creatively, but they show no skills in the pragmatics of syntax. In contrast, even before language begins, human infants engage with others in unique forms of cooperative communication via deictic and symbolic gestures, which already distinguish pragmatically between a common ground topic and its perspectival focus. Evolutionarily, event-participant conceptual organization and topic-focus pragmatic organization formed the foundation for the conventionalization of syntactically structured human languages.

Abstract This chapter reviews the primate research literature on primate culture and social learning mechanisms and strategies. The chapter begins with an historical account of primate cultures, most notably those of chimpanzees but also orangutans, capuchins, and Japanese macaques. It describes the cultural repertoires and the social learning mechanisms that may support them. The next section focuses on the social learning mechanisms involved in foraging including food choice, tool use, and food extraction. Special attention is devoted to the phenomena of conformity and conservatism. It also includes studies on social transmission chains and the question of cumulative culture. Next, the chapter focuses on the social learning of actions (outside foraging) including vocalizations, gestures and non-instrumental actions. It also presents the data on imitation recognition. The last section of this chapter is devoted to social learning strategies including model-based learning, frequency-based learning, and teaching.

Abstract In joint agencies, toddlers coordinate their intentional actions with other intentional agents in species-unique ways by creating both joint goals and joint attention. The social-cognitive capacities empowering the creation of joint goals and attention are what we may call joint intentionality. To facilitate this coordination, toddlers develop, in addition, species-unique forms of cooperative-referential communication, beginning with the simple but powerful pointing gesture, followed by symbolic (including linguistic) communication. The evolutionary hypothesis is that only humans evolved to co-operate in all these ways because only they evolved in the face of ecological challenges requiring collaborative activities structured by joint intentionality. This chapter provides a review and novel analysis of the literature on toddler-shared cognition, based on the principles of joint agency and perspectival representations.

Abstract The working hypothesis of this chapter is that what accounts for these new cognitive capacities, and others, is that children from three to six years of age are in the process of becoming metacognitive agents who reflectively regulate their executive-tier conceptualizing, thinking, and decision-making. What makes this rational/reflective mode of operation possible is a new organizational architecture that builds on top of toddlers’ executive tier of regulation a second-order executive tier, a metacognitive tier, of regulation. This chapter provides a review and novel analysis of the literature in preschoolers’ cognition based on the principles of metacognitive agency and multi-perspectival representations.

Abstract This chapter provides a review and novel analysis of the literature of preschoolers’ shared cognition based on the principles of collective agency and objective/normative representations. As preschool youngsters are becoming ever more competent and independent as individual agents, they are at the same time becoming ever more dependent on the social group in which they live. To find their way in the group children must not only make many of their own decisions, but they must also conform to the way things are conventionally and normatively done in the group—such that they are able to collaborate and communicate effectively with all its members, including those they have never met before. Preschool youngsters are gradually coming to identify with a collective “we,” encompassing not just collaborative partners of the moment but everyone who identifies with “our” ways of doing things.