Introduction

The biological model of life history is very particular to the human species. It is characterized by a long period of development, including an intermediate period between childhood and adulthood (adolescence), and a large brain relative to adult body mass. The human brain is equipped with complex “neuronal wiring”, which takes around ten years to set up. This wiring of the human brain, linked to the particular rhythm of cerebral development, is at the origin of human cognitive capacities. Unlike other primates, which are precocial mammals, human development is altricial (or secondary), because the human baby is born with a small brain, relative to its adult size, and this brain takes a long time to reach the adult stage of maturation (around a quarter of the average longevity of the individual). For a large part of its development, the human child is, because of the altriciality of its species, particularly vulnerable and dependent on its parents and the adults in its family and social group.

Human societies have therefore had to integrate this long period of biological immaturity, unique in its duration among other species of higher primates (Hominidae) living in societies (orangutans, chimpanzees, gorillas). The development of altruistic behaviours at parental, family and social levels, already identified in certain mammals, including the great apes (e.g. Boesch et al. 2010), must have accompanied the establishment of altriciality in the human species. This biological trait was acquired relatively late in the evolutionary process, since it was not yet present in the ancient representatives of the erectus species, whereas it has been perfectly demonstrated in Neanderthals (Coqueugniot et al. 2004). The generalization of these self-help social behaviours becomes evident in recent prehistoric periods, with archaeological evidence of the demographic explosion of human societies, with no comparison to hominid primate societies, living in small groups of a few dozen individuals.

Studying the evolution of behavior during the hominization process requires the involvement of other disciplines, including ethology, comparative psychology and sociology. Anthropology and sociology have theorized the question of the “social bond”, mutual aid or solidarity (Durkheim 1893 ; Paugam 2008), and have often placed at the heart of human societies the question of exchange (of goods, services and women) (Lévi-Strauss 1949), of gift and counter-gift (Mauss 1924), of selflessness, sacrifice or self-sacrifice characterizing intra-family relationships, and in particular parent-child relationships, but also love relationships (Bourdieu 1998). In the most anthropological part of his work, Darwin (1871) also emphasized the role of “social instincts” in the human species, and its ability to use specific laws and institutions to combat the “processes of elimination” of the weakest (the disabled, the insane, the sick, the poor, etc.). Sociology has often emphasized the fundamental importance of the infant's long dependence in understanding the powerful cultural determinisms that weigh down the first few months of a human child's life (Lahire 2019), without however highlighting the equally important fact that this situation of secondary altriciality and long dependence necessitates the strengthening of bonds of solidarity and mutual aid. Unlike other animal species, the human baby is a very premature social infant who owes its survival and psychomotor and psycho-cognitive development to the scaffolding processes (in the sense of guidance) (Bruner 1991) of the adults who carry the culture necessary for its survival in a given social group and environment.

We owe to experimental psychologist and psychoanalyst John Bowlby (2002) the precise study of what he called the “attachment relationship” between mother (or mother substitute) and child, with all the innate behaviors that facilitate the bond between the partners in the interaction (facial mimicry, smiling, crying and, of course, very quickly, language). From our point of view, Bowlby's approach is of particular interest in that it situates the mother-child relationship specific to the human species within the history of mother-child relationships in all mammals (and not just primates). The work of American cognitive psychologist Michael Tomasello (2015), who compares the cognitive properties of human babies and babies of other primate species, shows that with their capacity for joint attention and action, and their ability to speak, humans are distinguished from other animals not only by their strong capacity for communication, imitation and learning, which determine their exceptional ability to accumulate, generation after generation, the most sophisticated cultural achievements, but also by their strong propensity to cooperate and help each other in times of difficulty.

We intent to tighten the links between paleoanthropology and the humanities and social sciences, by building bridges between knowledge (theories and scientifically established facts) that do not usually communicate with each other. The humanities and social sciences, and especially sociology, which is undoubtedly, by virtue of its history, the social science best placed to build a general theoretical framework useful to all particular social sciences (cf. Testart 2021), nevertheless suffer from two major shortcomings: 1) the historical break with the achievements of evolutionary biology and ethology (or behavioural ecology), which prevents it from reinscribing human behaviour in a very long-term history of non-human animal societies, and 2) the presentism of researchers who work essentially on contemporary societies. On the first point, the scientific need to build its scientific autonomy by defining social facts irreducible to all other facts (and in particular psychological and biological facts) (Durkheim, 1895), coupled with the rejection of Edward O. Wilson's reductionist sociobiology (1975), have contributed to breaking all links between scientific communities that are all working on social structures and social behaviour.

With regard to the second point, both sociology and anthropology today suffer from a “withdrawal into the present” (Elias, 2003), which prevents them from drawing on a broad knowledge of the past of human societies (Testart, 2009). This has not always been the case, as the great founders of the social sciences (Durkheim, Weber and Marx) were able to mobilize extensive knowledge of all known human societies through historiography or ethnography. By combining the respective strengths of our disciplines, and by compensating for their weaknesses through a process of mutual cross-fertilization of our knowledge, we will be able to take a step forward on this central question (secondary altriciality and mutual aid) towards a better understanding of the characteristics specific to all human societies.