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Group size, vocal grooming and the origins of language
Abstract
I argue that speech and language evolved through a series of stages individually designed to break through successive glass ceilings on group size. Language was simply the last of these (and hence evolved late in hominin evolution), but its precursors (laughter and singing) each played a crucial role in preparing the way for speech production.
... We now present a well-developed hypothesis, due to Robin Dunbar (2012Dunbar ( , 2014Dunbar ( , 2017, about a selective mechanism for laughter-like vocalisation in the late hominin-early Homo period (roughly 3-1mya). Dunbar and colleagues have long been interested in the selective advantages and costs of varying group sizes and living patterns in species of primates and other social animals. ...
... A crucial mediating factor, it is argued, is so-called 'social grooming' which involves pairs of individuals stroking, picking and cleaning each other's bodies. Dunbar (2012Dunbar ( , 2017 and others argue that social grooming, which is common among primates but rare in other mammals, triggers release of the opioid brain chemical endorphin, thereby creating pleasurable feelings, calming tensions, and promoting bonding between pairs of individuals who groom one another. Obviously, social grooming can only occur when individuals are together, at rest, and safe. ...
... Modern human hunter-gatherers, however, typically live in much larger groups (~150) and there is evidence from the fossil record that late hominins and early Homo broke through the glass ceiling of 50 individuals 1. For Dunbar (2012Dunbar ( , 2017, the question comes down to this: How could individuals have triggered endorphin release in others in a more time-efficient fashion than physical grooming? His answer is that laughter (laughter-like vocalisation) provided such a mechanism. ...
This paper combines perspectives from evolutionary biology and linguistics to discuss the early evolution of laughter and the possible role of laughter-like vocalisation as a bonding mechanism in hominins and early human species. From the perspective of evolutionary biology, we here emphasise several things: the role of exaptation, the typically very slow pace of evolutionary change, and the danger of projecting backwards from the current utilities of laughter to infer its earlier function, hundreds of thousands, or even millions, of years ago. From the perspective of linguistics, we examine both the semantics of the word ‘laugh’ and the vocal mechanics of human laughter production, arguing that greater terminological care is needed in talking about the precursors of laughter in the ancient evolutionary past. Finally, we turn to hypotheses about how laughter-like vocalisations may have arisen, long before articulate language as we know it today. We focus in particular on Robin Dunbar’s hypothesis that laughter-like vocalisation, which stimulated endorphin production, might have functioned as a bonding mechanism (a kind of “vocal grooming”) among hominins and early human species. The paper contributes to the special issue theme (Humour and Belonging) by casting a long look backwards in time to laughter-like vocalisation as a distant evolutionary precursor of humour, and to bonding as an evolutionary precursor to cognitively and socially modern forms of “belonging”. At the same time, it cautions against casual theorising about the evolutionary origins of laughter.
... Underlying the advances already outlined, connecting diet, brain size, and social complexity, is the social brain hypothesis, which stipulates that across all primates, social group size correlates with brain size (Dunbar 2017). Increases in group size yield an increase in social complexity and increased rates of innovation (Derex et al. 2013). ...
... Given the limited time available for social bonding, the physical restrictions of social grooming as a one-on-one activity initially limited hominin group sizes to about 50 members. Around the emergence of H. ergaster/erectus, laughter likely evolved as a way to socialize more effectively, as laughter naturally occurs in groups of about three, accounting for the expansion of hominin group sizes until around 500 kya (Dunbar 2017). To account for the larger hominin group sizes that arose after around 500 kya, Dunbar (2017) proposes that singing or musical chorusing that could take place around a hearth was invented to meet the social demands of larger group sizes. ...
... Around the emergence of H. ergaster/erectus, laughter likely evolved as a way to socialize more effectively, as laughter naturally occurs in groups of about three, accounting for the expansion of hominin group sizes until around 500 kya (Dunbar 2017). To account for the larger hominin group sizes that arose after around 500 kya, Dunbar (2017) proposes that singing or musical chorusing that could take place around a hearth was invented to meet the social demands of larger group sizes. Such songs were likely wordless initially, but they would eventually incorporate words, and soon other genres such as storytelling would also proliferate during evening social time. ...
Humans are unique in their creative abilities and this creativity likely arose as a result of self-domestication. Language use would have been a driver of early human self-domestication, and this paper examines how the controlled use of fire for cooking was an early driver in the development of language. Cooking allowed for greater caloric intake and a greater diversity of diet, contributing to larger hominin brain sizes and group sizes. These developments created new social constraints that were met by the emergence of language. Diets can impact neuroplasticity, enhancing divergent thinking and creativity. One potential source of such transformative foodstuffs were intoxicants, the use of which could have easily become ritualized and used as social and cognitive tools. Cooking and ritualization, as fundamentally hierarchically and temporally structured actions, are grounded in recursion, which is also a key aspect of language. Cooking, recursive, and symbolic thought coevolved, driving the development of language. This paper is part one of a two-part article.
... Robin Dunbar, an important contributor to the debate around the evolution of language, is of the opinion that '… speech and language evolved through a series of stages individually designed to break through successive glass ceilings on group size' (Dunbar 2017), and that: ...
... The overall benefit appears to be that singing, in contrast to laughter and grooming, seems to lack upper limit with regard to participants. Dunbar (2017) and others (Roebroeks & Villa 2011) also make the point that fire and the regular use of hearths started almost overnight: ...
... It is worthwhile to note that the people of PP13B were not only adept at the technological control of fire, but also able to draw on the added benefit of extending their day-time activities into the night by socialising around a fire, in contrast to non-human primates who were active only during the day and inescapably spent their nights in darkness. Dunbar (2017) is sensitive to this scenario when he states that the: ...
Articulate language is a form of communication unique to humans. Over time, a spectrum of researchers has proposed various frameworks attempting to explain the evolutionary acquisition of this distinctive human attribute, some deploring the apparent lack of direct evidence elucidating the phenomenon, whilst others have pointed to the contributions of palaeoanthropology, the social brain hypothesis and the fact that even amongst contemporary humans, social group sizes reflect brain size. Theologians have traditionally (largely) ignored evolutionary insights as an explanatory paradigm for the origin of humankind. However, an increasing number are, of late, contributing to a worldview of humanity which accommodates both the epistemological realities of evolutionary biology as well as insights from theology. This includes reviewing and assessing the origins of articulate language and the physiological attributes necessary for its development. It is in this sense that the evolution of language is relevant from a theological perspective. The association between mental capacity and articulate language, already noted by Darwin, is relevant in explaining the larger group sizes found amongst humans, as is the incipient role played by the evolution of laughter in triggering the neuroendocrine system promoting bonding, to the eventual development of articulate language. Our aim is to review a selection of contemporary perspectives on the evolution of language, amongst others, reasons for the ease with which young children acquire language competency, and whether we may be hardwired for language from birth. Further reading is suggested in the footnotes.
Contribution: This article is part of a special collection reflecting on the evolutionary building blocks of our past, present and future. It is based on historical thought and contemporary research with regards to the evolutionary emergence of language. It fits well with the intersectional and trans-disciplinary nature of this collection and journal.
... Plusieurs hypothèses ont été suggérées dans la littérature concernant les origines des capacités musicales humaines. Notamment, plusieurs auteurs (Darwin, 1871 ;Roederer, 1984 ;Dissanayake, 2000 ;Miller, 2000 ;Dunbar, 2017) ont suggéré que la musicalité pourrait avoir une origine biologique et évolutive : elle pourrait avoir été favorisée au cours de l'évolution car elle apporterait un avantage adaptatif aux individus, c'est-à-dire un avantage en termes de survie et/ou de succès reproducteur (Darwin, 1871). Cependant, les positions de ces auteurs divergent concernant la nature de l'avantage adaptatif qui pourrait être associé aux capacités musicales. ...
... En effet, la musicalité pourrait être un véritable moyen de communication des émotions, via la voix mais aussi la synchronisation des mouvements (voir aussi Malloch, 1999 ;Malloch et Trevarthen, 2009). D'autres auteurs ont émis l'idée que la musique favoriserait plus largement les liens sociaux et la cohésion du groupe, et ainsi la survie des individus qui le composent (Roederer, 1984 ;Freeman, 1998 ;Dunbar, 2017). Par exemple, selon Freeman (1998), l'écoute de musique pourrait placer les individus dans de meilleures dispositions pour coopérer avec autrui, en modifiant leur état émotionnel par des mécanismes neuro-hormonaux. ...
... Par ailleurs, en tant qu'activité traditionnellement collective nécessitant des interactions fortes entre les individus, la production musicale pourrait participer à créer et entretenir les liens sociaux spécifiquement au sein du groupe dont les membres partagent cette expérience (Roederer, 1984). Enfin, Dunbar (2017) va plus loin en suggérant que la musique puis le langage pourraient avoir remplacé le toilettage mutuel comme « ciment social », à une période de notre histoire où celui-ci aurait pris trop de temps pour assurer la cohésion de groupes sociaux devenant de plus en plus larges. Le langage et la musique semblent d'ailleurs partager certaines caractéristiques : ils sont aussi efficaces l'un que l'autre pour communiquer des émotions, et les signaux accoustiques associés à chaque émotion y sont similaires (Scherer, 1991 ;Juslin et Laukka, 2003). ...
La musicalité ( i.e. l’ensemble des capacités associées à la perception, à l’appréciation et la production musicale) est largement répandue chez notre espèce. Selon certains chercheurs, elle aurait évolué car elle favoriserait la survie et/ou la reproduction. Ainsi, les origines biologiques de la musicalité ont été étudiées dans la littérature, chez l’espèce humaine mais aussi chez d’autres espèces. Les études suggèrent des fonctions adaptatives, dont l’attractivité en tant que partenaire de reproduction, la communication mère-bébé, ou encore la cohésion des groupes sociaux. Dans cette revue comparative, nous présenterons les données existantes sur la musicalité chez les espèces humaine et non-humaines pour chacune des fonctions évoquées ci-dessus. Nous discuterons ensuite la convergence évolutive de la musicalité chez certaines espèces ainsi que son origine biologique.
... Moreover, with the advent of language came a move away from grooming. Being able to have more conversational partners meant that groups could become larger (Dunbar, 2017). Larger groups and being able to have more interaction partners at one time would have alleviated pressure on the individual because there would have been more real available interaction time to go around. ...
... Crucially, language moved conspecific interaction away from the dyad. An individual can only groom one other individual, but they can speak with two, three, four, or more individuals (Dunbar, 2017). The majority of interactions would be with groups. ...
This article discusses dominance personality dimensions found in primates, particularly in the great apes, and how they compare to dominance in humans. Dominance traits are seen in virtually all primate species, and these dimensions reflect how adept an individual is at ascending within a social hierarchy. Among great apes, dominance is one of the most prominent personality factors but, in humans, dominance is usually modeled as a facet of extraversion. Social, cultural, and cognitive differences between humans and our closest ape relatives are explored, alongside humanity’s hierarchical and egalitarian heritage. The basic characteristics of dominance in humans and nonhuman great apes are then described, alongside the similarities and differences between great apes. African apes live in societies each with its own hierarchical organization. Humans were a possible exception for some of our history, but more recently, hierarchies have dominated. The general characteristics of high-dominance humans, particularly those living in industrialized nations, are described. Dominance itself can be subdivided into correlated subfactors: domineering, prestige, and leadership. Various explanations have been posed for why dominance has declined in prominence within human personality factor structures, and several possibilities are evaluated. The value of dominance in personality research is discussed: dominance has links to, for instance, age, sex, aggression, self-esteem, locus of control, stress, health, and multiple socioeconomic status indicators. The piece concludes with recommendations for researchers who wish to assess dominance in personality.
... Models aiming to explain cooperation that do not rely on genetic selection suggest that information about an individual's likely future behaviour guides preferential treatment and cooperation [36][37][38][39][40][41]. This information may be gained directly, based on how one was treated by the target individual (direct reciprocity; [42]), based on one's observations of how the target individual treats others (indirect reciprocity; [42][43][44][45][46][47]) or based on information one receives from third parties about the target individual (gossip; [48][49][50][51][52][53][54]). ...
... The improved ability to remember and use information about other individuals comes at a substantial cognitive and temporal cost [50,[55][56][57]. Increasing costs may have selected for categorization of others based on readily observed signals [58,59]. ...
Mimicry is an essential strategy for exploiting competitors in competitive co-evolutionary relationships. Protection against mimicry may, furthermore, be a driving force in human linguistic diversity: the potential harm caused by failing to detect mimicked group-identity signals may select for high sensitivity to mimicry of honest group members. Here we describe the results of five agent-based models that simulate multi-generational interactions between two groups of individuals: original members of a group with an honest identity signal, and members of an outsider group who mimic that signal, aiming to pass as members of the in-group. The models correspond to the Biblical story of Shibboleth, where a tribe in conflict with another determines tribe affiliation by asking individuals to pronounce the word, ‘Shibboleth.’ In the story, failure to reproduce the word phonetically resulted in death. Here, we run five different versions of a ‘Shibboleth’ model: a first, simple version, which evaluates whether a composite variable of mimicry quality and detection quality is a superior predictor to the model’s outcome than is cost of detection. The models thereafter evaluate variations on the simple model, incorporating group-level behaviours such as altruistic punishment. Our results suggest that group members’ sensitivity to mimicry of the Shibboleth-signal is a better predictor of whether any signal of group identity goes into fixation in the overall population than is the cost of mimicry detection. Thus, the likelihood of being detected as a mimic may be more important than the costs imposed on mimics who are detected. This suggests that theoretical models in biology should place greater emphasis on the likelihood of detection, which does not explicitly entail costs, rather than on the costs to individuals who are detected. From a language learning perspective, the results suggest that admission to group membership through linguistic signals is powered by the ability to imitate and evade detection as an outsider by existing group members.
... Another significant driver of sociality, beyond the "strength-in-numbers" and rhythmic synchronisation arguments discussed in §2.3.2, is the vocal grooming hypothesised by Aiello and Dunbar (1993) and Dunbar (2017) to have underpinned social relationships in hominin societies. A common behaviour in primates is ritualised physical contact, in the form of reciprocal "stroking and patting" (Dunbar, 2017, p. 209), termed grooming. ...
... and was built upon existing signal systems" (2020, p. 3). Moreover, the association of lip-smacking with (physical) grooming in chimpanzees supports Dunbar's (2017) hypothesis for the role of vocal grooming in the evolution of human (musi)language ( §2.3.5). As argued in Chapter 2, various adaptations and exaptations in biological and cultural evolution -of which vocal learning' was surely central -built upon these "existing signal systems" in humans in ways that led to the evolution of musilanguage and then, via music and language, to the Cognitive Revolution. ...
Music in Evolution and Evolution in Music by Steven Jan is a comprehensive account of the relationships between evolutionary theory and music. Examining the ‘evolutionary algorithm’ that drives biological and musical-cultural evolution, the book provides a distinctive commentary on how musicality and music can shed light on our understanding of Darwin’s famous theory, and vice-versa.
Comprised of seven chapters, with several musical examples, figures and definitions of terms, this original and accessible book is a valuable resource for anyone interested in the relationships between music and evolutionary thought. Jan guides the reader through key evolutionary ideas and the development of human musicality, before exploring cultural evolution, evolutionary ideas in musical scholarship, animal vocalisations, music generated through technology, and the nature of consciousness as an evolutionary phenomenon.
A unique examination of how evolutionary thought intersects with music, Music in Evolution and Evolution in Music is essential to our understanding of how and why music arose in our species and why it is such a significant presence in our lives.
... From some evidence it may be estimated that the social size of groups for the early ancestor, Homo erectus, were about 15 to 23 (Hatala et al 2016), and for Neanderthals ranged from about 12 to 25 people (Hayden 2012), which are consistent with high levels of reactive aggression in our ancestors and also for Neanderthals. In comparison, for early Homo sapiens the average group size was about 50 people, and through further evolution rose to around 150 in modern humans (Dunbar 2017). The increase in numbers of people in a hunter gatherer group, allowed more cooperation such as in building infrastructure, such as common food stores and sleds for travel in winter (Wrangham 2020: pp. ...
... They may have temporarily formed alliances with around 8 groups, so to a total of around 200 strong, for mounting drives (Hayden 2012). In contrast, groups of early Homo sapiens were significantly larger, of about 50 people, which through further evolution rose to around 150 in modern humans (Dunbar 2017). ...
At this stage in human evolution, as we stand looking to the future, we and the other fauna and flora species of planet earth, are at most risk ever of seriously decreasing quality of life on our planet, due to climate change and loss of biodiversity, which are both critical to our quality of life.
How did we get here? From the beginning of agriculture, around 12,500 years ago, population growth became the key driver, which was limited by agricultural productivity. So, growth in population was suppressed by famine or collapse due to changes in environment or climate. Then, there was a continuing fear that food might become scarce. Fourteen centuries later, the fear of scarcity remains a central driver in the modern industrial economy.
Also, first farmers worked to transform natural spaces into domestic and cultural spaces. This was the start of the perception that human activities were separated from the natural environment, and the perception that human activities caused no significant damage to the natural environment.
The common idea that money begets money has its origin in livestock farming, influenced by the reproductive capacity of cattle from the agricultural era. This led to people focusing on collecting money for its own purpose, as a measure of personal wealth.
The division of labour in Roman cities cemented a patriarchal social hierarchy, which has continued through today.
Then, in the industrial era the perceived scarcity of material things became a key social personal driver. This was activated by aspiration, jealousy and desire, rather than absolute need. The outcome was to work long hours, attempt to climb the social ladder, and to keep up with the Joneses. This also became a major driver on ever increasing economic production, and so ever more consuming non-renewable resources and degradation of the natural environment.
I then discuss solutions to these social and environment issues, including via their current basis on Liberalism and Neoliberalism. To summarise, we shall move from a primarily materialist society, to a primarily relational society.
... Allo-grooming and allo-preening are widespread in mammals and birds respectively and can serve important hygienic (e.g., ectoparasite removal); stress alleviation (e.g., deescalate conflicts, lower glucocorticoid levels); and social signaling functions (e.g., formation and maintenance of social bonds and social hierarchies) (Bradbury and Vehrencamp 2011). Allo-grooming is especially important in maintaining social hierarchies in primates but is less effective in cases where groups are large and more dispersed and is thought to have favored the use of vocal recognition cues (McComb and Semple 2005;Arlet et al. 2015;Kulahci et al. 2015;Dunbar 2017). Vocal signatures are more efficient at monitoring social interactions in larger groups and can be heard over long distances, through dense vegetation and in complete darkness. ...
... Parrotlets that preened a relatively large number of siblings postponed their development of vocal signature learning. Allogrooming in primates is intimately related to contact calls especially in larger more dispersed groups and has been suggested to have eventually led to imitation of vocal signatures as a way of engaging social companions in large human groups (McComb and Semple 2005;Arlet et al. 2015;Kulahci et al. 2015;Dunbar 2017). Mammals and vocal learning birds, despite being separated by over 300 million years from a common ancestor, converged on similar gene expression patterns in late-developing brain regions that control vocal imitation (Pfenning et al. 2014), however, the behavioral modifications and ecological sources of selection that led to convergence in mammals and birds are still the subject of debate (Fitch et al. 2010;Nowicki and Searcy 2014). ...
Allo-grooming networks in primate social groups are thought to have favored the evolution of vocal recognition systems, including vocal imitation in humans, as a more effective means of maintaining social bonds in large groups. Select avian taxa converged on vocal learning, but it is not clear what role analogues of allo-grooming might have played. Unlike allo-grooming in most primates, allo-preening in birds is usually limited to pair-bonds. One exception to this is during nestling development when siblings preen each other, but it is unknown how allo-preening influences vocal learning. We addressed this question in wild Green-rumped Parrotlets (Forpus passerinus) in Venezuela. Nestlings learn signature contact calls from adult templates. Large broods, age hierarchies and protracted development in this species create the potential for complex allo-preening networks and a unique opportunity to test how early sociality makes the development of vocal learning labile. From audio-video recordings inside nest cavities and a balanced design of different brood sizes, we quantified allo-preening interactions between marked nestlings, to compare to signature contact calls. Controlling for brood size and age hierarchy, the propensity to preen a larger number of individuals (i.e., out-strength) correlated positively with the age at first contact call. Allo-preening and acoustic similarity matrices did not reveal clear correlations within broods, instead larger broods produced greater contact call diversity. Results indicate that allo-preening elongates the period during which contact calls develop, which might allow individuals time to form a unique signature under the computationally challenging social conditions inherent to large groups.
... Similarly, Dunbar's hypothesis of vocal grooming [137][138][139]161], which is based on a positive correlation between group size and grooming time, has also been heavily criticized in recent years [162,163]. Grueter et al. [162] argue that the association between group size and grooming time is confounded with substrate: they contend that grooming time should be higher in terrestrial (versus arboreal) species, given higher exposure to ectoparasites. ...
... However, the influence of music in synchronizing behaviours and promoting bonding (e.g. [179][180][181][182]) is consistent with hypotheses based on music playing a role in promoting group cohesion, as in Dunbar's theory of vocal grooming [137][138][139]161], or with hypotheses in which music functions as a credible signal for coalitional intent [153,183,184]. It is also manifest in group activities: for example, contemporary armies around the world march to music, and common analogous examples include rhymes and chants of sports fans and protesters. ...
Studies show that specific vocal modulations, akin to those of infant-directed speech (IDS) and perhaps music, play a role in communicating intentions and mental states during human social interaction. Based on this, we propose a model for the evolution of musicality—the capacity to process musical information—in relation to human vocal communication. We suggest that a complex social environment, with strong social bonds, promoted the appearance of musicality-related abilities. These social bonds were not limited to those between offspring and mothers or other carers, although these may have been especially influential in view of altriciality of human infants. The model can be further tested in other species by comparing levels of sociality and complexity of vocal communication. By integrating several theories, our model presents a radically different view of musicality, not limited to specifically musical scenarios, but one in which this capacity originally evolved to aid parent–infant communication and bonding, and even today plays a role not only in music but also in IDS, as well as in some adult-directed speech contexts.
This article is part of the theme issue ‘Voice modulation: from origin and mechanism to social impact (Part II)’.
... Similarly, Dunbar's hypothesis of vocal grooming [137][138][139]161], which is based on a positive correlation between group size and grooming time, has also been heavily criticised in recent years [162,163]. Grueter et al. [162] argue that the association between group size and grooming time is confounded with substrate: they contend that grooming time should be higher in terrestrial (vs arboreal) species, given higher exposure to ectoparasites. ...
... However, the influence of music in synchronising behaviours and promoting bonding [e.g. [179][180][181][182] is consistent with hypotheses based on music playing a role in promoting group cohesion, as in Dunbar's theory of vocal grooming [137][138][139]161], or with hypotheses in which music functions as a credible signal for coalitional intent [153,183,184]. It is also manifest in group activities: for example, contemporary armies around the world march to music and common analogous examples include rhymes and chants of sports fans and protesters. ...
Studies show that specific vocal modulations, akin to those of infant-directed speech and perhaps music, play a role in communicating intentions and mental states during human social interaction. Based on this, we propose a model for the evolution of musicality –the capacity to process musical information– in relation to human vocal communication. We suggest that a complex social environment, with strong social bonds, promoted the appearance of musicality-related abilities. These social bonds were not limited to those between offspring and mothers or other carers, although these may have been especially influential in view of altriciality of human infants. The model can be further tested in other species by comparing levels of sociality and complexity of vocal communication. By integrating several theories, our model presents a radically different view of musicality, not limited to specifically musical scenarios, but one in which this capacity originally evolved to aid parent-infant communication and bonding, and even today plays a role, not only in music but also in infant-directed speech (IDS), as well as some adult-directed speech (ADS) contexts.
... Dunbar, 2016a;Gonc xalves et al., 2011;Mac Carron et al., 2016), schizophrenia (Burns, 2006), the emergence of language (e.g. Aiello & Dunbar, 1993;Dunbar, 2003aDunbar, , 2003bDunbar, , 2017a and the evolutionary basis of religion (e.g. Dunbar, 2017bDunbar, , 2020. the material remains of the human past. ...
... Social cohesion among primates is strongly dependent on grooming, but its temporal element means that time acts as a constraint on the number of relationships that can be made and maintained . Dunbar (1993Dunbar ( , 2017a consequently suggests that language (potentially preceded by laughter) emerged as a solution to this issue: as a more efficient strategy that could 'groom' several individuals at the same time, language aided the maintenance of larger social networks. ...
The social brain hypothesis (SBH) has played a prominent role in interpreting the relationship between human social, cognitive and technological evolution in archaeology and beyond. This article examines how the SBH has been applied to the Palaeolithic material record, and puts forward a critique of the approach. Informed by Material Engagement Theory (MET) and its understanding of material agency, it is argued that the SBH has an inherently cognitivist understanding of mind and matter at its core. This Cartesian basis has not been fully resolved by archaeological attempts to integrate the SBH with relational models of cognition. At the heart of the issue has been a lack of meaningful consideration of the cog- nitive agency of things and the evolutionary efficacy of material engagement. This article proposes MET as a useful start- ing point for rethinking future approaches to human social cognitive becoming in a way that appreciates the co- constitution of brains, bodies and worlds. It also suggests how MET may bridge archaeological and 4E approaches to reconsider concepts such as the ‘mental template’ and Theory of Mind.
... Indeed, language is one, if not the most, powerful tool in transmitting information with high fidelity and might have been selected for this purpose (Pinker, 1994;Pinker & Bloom, 1992). According to Dunbar, language has evolved to facilitate the transmission of social information that was crucial to maintain social bonds under increasing group sizes (Aiello & Dunbar, 1993;Dunbar, 1993Dunbar, , 2016. In non-human primates, grooming serves to maintain social relationships and the amount of time spent during grooming linearly correlates with the group size (Dunbar, 1991). ...
... Dunbar states that in humans, language replaced the function of grooming, because otherwise 40% of the hominin time would have to be dedicated to grooming under increasing population sizes (Dunbar, 1993). Whereas grooming has to be a one-to-one interaction, speaking made simultaneous connections with many individuals in the group possible (Aiello & Dunbar, 1993;Dunbar, 2016). ...
Hunters and gatherers occupied 95% of the human history. Despite the forces of globalization, current-day hunter-gatherers can shed light on how we adapted to different environments and generated complex cultural traits. Their changing ways of life, on the other hand, may let us understand cultural change. In this thesis, I explore the cultural evolution of plant knowledge in an extant hunter-gatherer population, the Mbendjele BaYaka Pygmies from the Northern Republic of Congo. In Chapter 4, I show that the Mbendjele use wild plants for various reasons from treating digestive system disorders to punishing norm violators. In Chapter 5, I investigate whether there are adaptive benefits to the use of certain medicinal plants and explore the common uses of medicinal plants across different Pygmy populations and great apes. I also explore the known bioactive compounds, and test the effects of mothers’ use of certain medicinal plants on their children’s body- mass-index. In Chapter 6, I investigate how the Mbendjele have evolved such a rich plant use repertoire by exploring sharing of medicinal and non-medicinal plant knowledge with respect to features of social structure. I argue that the long-term pair bonds, marital ties and cooperative breeding have allowed the Mbendjele to combine and accumulate rich medicinal plant uses. Additionally, co-residence of multiple families provides a context for the sharing and accumulation of plant uses that concern cooperative foraging and social norms. In Chapter 7, I explore the socioeconomic transitions in the Mbendjele that live in a logging town and examine how plant knowledge declines with their changing life-style. I argue that change in subsistence activities, emerging inequalities and decreased mobility hinder the transmission of traditional knowledge. Nevertheless, I argue that adoption of new cultural traits may be inevitable and beneficial for the resilience of modern day hunter-gatherers.
... There must have been strong selective forces for this to happen, and that selection was almost certainly involving higher cognitive abilities in foraging, social interaction and communication. This was probably accompanied by the evolution of a smaller gut over time and the incorporation of a higher quality diet, with consumption of higher amounts of meat and marrow (Aiello and Wheeler 1995), the presence of larger social group sizes (Dunbar 1993(Dunbar , 2017Schoenemann 2006;Dunbar et al. 2014) and a more efficient search/processing/consumption pattern (Herculano-Houzel 2016). Dunbar (2017) argues that, prior to language, laughter and singing were probably important means of vocal grooming in the hominin social group, laying the foundations for the development of language per se. ...
... This was probably accompanied by the evolution of a smaller gut over time and the incorporation of a higher quality diet, with consumption of higher amounts of meat and marrow (Aiello and Wheeler 1995), the presence of larger social group sizes (Dunbar 1993(Dunbar , 2017Schoenemann 2006;Dunbar et al. 2014) and a more efficient search/processing/consumption pattern (Herculano-Houzel 2016). Dunbar (2017) argues that, prior to language, laughter and singing were probably important means of vocal grooming in the hominin social group, laying the foundations for the development of language per se. ...
This paper focuses on the empirical evidence for the cognitive abilities of early hominins of the Oldowan Industrial Complex (c. ≥2.6 to 1.4 Mya) on the African continent. It profiles various researchers’ approaches to and inferences about the cognitive abilities of Oldowan (Mode 1) toolmakers, based on the excavated archaeological evidence, primate models, experimental archaeology and neuroimaging techniques. Although there is a great deal of variation with regard to how to interpret such evidence, a variety of archaeological and palaeoneurological evidence indicates that Oldowan hominins represent a stage of technological and cognitive complexity not seen in modern great apes (chimpanzees, bonobos, gorillas, orangutans), but transitional between a modern ape-like cognition and that of later Homo (erectus, heidelbergensis, sapiens). Prevailing evidence and evolutionary models suggest that this new evolutionary stage entailed the growing elaboration of a problem-solving, technological niche that incorporated manufactured tools as a critical component of adaptation, especially to enhance food procurement and processing, as well as enhancements and greater complexity in social behaviours and communication.
... Yet the small fraction of coding and regulatory genetic differences between humans and our closest living relatives leads to some remarkable behavioral specializations. Perhaps the most notable traits distinguishing us from other primates are our unique socio-communicative abilities, which have been crucial for the evolution of human cultural cognition, including language [2][3][4]. ...
... Although the exact origin of language in the human lineage remains under debate, theories suggest that it may have co-evolved in parallel with changes in social cognition [9,14 ], for example to facilitate the bonding of large social groups [4], or to solve increasingly complex social problems [2,3,15]. This has important consequences for studying the genetic mechanisms underlying the evolution of speech and language, as aside from investigating genes involved in orofacial and laryngeal motor control, the focus should also be inclusive of genetic variation more broadly associated with social cognition in primates. ...
Although many studies stress the distinctive aspects of human language abilities, others argue that its foundations stem from a complex reconfiguration of ancestral systems that are shared with other species. This homology is crucial for identifying the genetic basis of human language, as much of the current research focuses on the recent evolutionary changes of the human genome. Here we provide a review of studies describing genetic variation related to socio-communicative abilities in great apes. As human language potentially evolved in tandem with changes in social cognition, it is important to expand our candidate gene selection to those associated with both social and communicative skills in nonhuman primates to obtain a more complete picture of the genetic architecture underlying language.
... One is gesturing, a specific way of social communication that is considered a precursor or foundation for the evolution of language (Sterelny, 2012;Hobaiter and Byrne, 2014;Graham and Hobaiter, 2023). Finally, and not mutually exclusively, language evolution has been proposed to be motivated and intertwined with social interaction, with language relieving the pressure of social survival by replacing grooming behavior and sharing a cognitive mechanism with social cognition such as the theory of mind (Dunbar, 1998(Dunbar, , 2003(Dunbar, , 2017Fitch et al., 2010;Oesch and Dunbar, 2017;Rajimehr et al., 2022). Investigating whether and how the genetic effects underlying neural activities in language processing are related to the genetic effects underlying these processes is one way to parse the potential genetic patterns underlying language neural networks. ...
Language is an evolutionarily salient faculty for humans that relies on a distributed brain network spanning across frontal, temporal, parietal, and subcortical regions. To understand whether the complex language network shares common or distinct genetic mechanisms, we examined the relationships between the genetic effects underlying the brain responses to language and a set of object domains that have been suggested to coevolve with language: tools, faces (indicating social), and body parts (indicating social and gesturing). Analyzing the twin datasets released by the Human Connectome Project that had functional magnetic resonance imaging data from human twin subjects (monozygotic and dizygotic) undergoing language and working memory tasks contrasting multiple object domains (198 females and 144 males for the language task; 192 females and 142 males for the working memory task), we identified a set of cortical regions in the frontal and temporal cortices and subcortical regions whose activity to language was significantly genetically influenced. The heterogeneity of the genetic effects among these language clusters was corroborated by significant differences of the human gene expression profiles (Allen Human Brain Atlas dataset). Among them, the bilateral basal ganglia (mainly dorsal caudate) exhibited a common genetic basis for language, tool, and body part processing, and the right superior temporal gyrus exhibited a common genetic basis for language and tool processing across multiple types of analyses. These results uncovered the heterogeneous genetic patterns of language neural processes, shedding light on the evolution of language and its shared origins with tools and bodily functions.
... Grooming may also not be of particular relevance in a variety of primate species where it is infrequently observed. Just as humans have opted for other behaviours to cement social bonds, such as language (Dunbar, 2017;Goffman, 2010), other behaviours may better indicate social bonds in gorillas and other mammals. For example, gazing and eye contact may be important in gorilla social dynamics (Watts, 1998;Yamagiwa, 1992). ...
Strong, affiliative relationships are important across social mammals, and in many species, relationships between female kin form the basis of group life. Relationships are expected to be weaker in cases where females disperse or do not cooperatively defend resources. Mountain gorillas, Gorilla beringei beringei, seem to support this, as females can emigrate multiple times throughout their life and do not jointly defend the abundant vegetation they feed on. Unsurprisingly, mountain gorillas have been reported to form variable or weak relationships with other females and seemingly prioritize relationships with adult males. But prior studies may have misinterpreted relationships due to a focus on grooming and understandable limitations of small sample sizes and short study periods. Here, we examine proximity and grooming between 47 adult female mountain gorillas in five groups over 5e13 years. We analyse proximity data (2 m, 5 m) and grooming relationships between 366 individual dyads to determine (1) whether proximity and grooming relationships are preferential and (2) whether they endure across time. Most females formed at least one preferential 2 m and 5 m proximity relationship (43 of 47), which both lasted a mean of 2.1 years. Additionally, 3.6% of dyads (N = 13/366) formed enduring 2 m proximity preferences that exceeded 4 years, with the longest lasting at least 12 years. Maternal kin had the most enduring proximity and grooming relationships, although grooming was rare overall. The enduring proximity relationships between some female gorillas in our sample are similar in length to those of female yellow baboons, Papio cynocephalus, and male chimpanzees, Pan troglodytes, which are considered social bonds. Mountain gorillas provide a system in which factors influencing bonds can be better understood, and our study highlights a need to refine definitions of social bonds while potentially reassessing their evolutionary function.
... In a quantitative study that observed natural social groups from three different countries (UK, France and Germany), it was found that laughter subgroups have an optimal size that depends on the size of the whole social group -3.35 members for social groups of size about 7 (Dezecache and Dunbar 2012). This is in line with evolutionary arguments highlighting the emergence of laughter and humor as a group-level social grooming behavior, where the release of endorphins together with emotional contagion processes led to bonding and cohesion (Dunbar 2017;Gervais and Wilson 2005;Van Vugt and Kameda 2013). ...
While most of the literature has focused on the individual-level effects of humor, the number of studies addressing and analyzing humor in its social context as a group-level phenomenon has also started to increase. Yet there is still increased heterogeneity of results, as well as problems regarding conceptualization and measurement of humor in groups. To further our understanding of humor as an emergent multilevel construct, we conducted a systematic literature review on the antecedents and consequences of humor in groups. The findings indicate that factors such as group composition, interpersonal familiarity, task structure, trust, cohesion, positive team environment, communication norms, communication channels, and timing dynamics play important roles in the emergence and type of humor expressed within groups. The consequences of humor in groups include the emergence of cohesion, the delineation of group boundaries and identity formation, influence on group atmosphere and affective dynamics, facilitation of collective coping and team engagement, and potential effects on team performance. We discuss research progress and gaps, and conclude by outlining future research directions.
... During their limited time of resting, social interactions should be allocated in favor to more valuable relationships, for residential males and females, within-unit bonds. For the out-unit relationships, in contrast, vocal communication provides an economical solution (i.e., vocal grooming: Dunbar, 2017). Alternatively, considering the more uncertain and riskier between-unit relationships, social evolution could have favored vocal communication for cultivating bonds and reassuring a liation when interacting, potentially as replacements for more 'stressful' forms of a liative interactions (e.g., approaching, greeting, grooming). ...
The ability to cultivate social relationships through language is human uniqueness. However, despite small repertoire sizes, nonhuman primates could use vocalization for social purposes too. Vocal communication could be evolutionarily ancient, and likely evolved hand-in-hand with complex, dynamic social structures. By studying the vocal communication in wild golden snub-nosed monkeys ( Rhinopithecus roxellana ), a species of Asian colobine living in 4-layer multi-level societies with fission-fusion dynamics, we unraveled the complex social functions of contact ‘coo’ calls. Contact calls helped cultivate both within- and between-unit relationships, and depending on the sexes, reproductive states, and social roles of callers and recipients, were also functionally diverse. Within units, calls replaced grooming and were supplementary to social proximity. Males directed more calls to lactating females, who were unavailable for grooming and away from unit centers due to extended foraging and childcare. Higher-ranking males called more frequently but did not receive more calls than lower-ranking ones. Considering their larger social network sizes and leadership roles, contact calls likely facilitated inter-unit proximity and were used for advertising intrasexual affiliation and alliances. By comparing the network of contact call exchange with that of social proximity and grooming, we identified the inter-unit social relationships that were otherwise inconspicuous and, more importantly, the potential mechanisms for maintaining male-male alliances and unit and band cohesion. Together with previous findings, we conclude that contact calls are economical and low-risk social tools for reassuring and advertising affiliation, resolving uncertainties, and promoting cohesion and alliance formation.
... While that is obvious with memeplexes that make up cultural practices central to the collective -its religion, perhaps, or its warrior code -, it is perhaps less obvious for the many small and trivial ones (Dawkins's early examples for memes include catchy tunes and ways of shaping vases). It should be seen, however, that producing and reproducing a sense of belonging, in a way 'grooming' (Dunbar, 2017), is one of the great problems of a collective. As the authors all live abroad, we can attest that 'belonging' requires familiarity with the host country's many and varied cultural references -which take years to acquire even if one learns the language rather quickly. ...
... Human social groups bond through gossiping and storytelling (33,34). The act of storytelling personally significant events and contemplating towards lessons learnt and future actions, confers benefit for people living with chronic pain (35). ...
In this perspective paper, we argue for incorporating personal narratives in positive psychology interventions for chronic pain. Narratives refer to the telling and retelling of events. Narratives detail accounts of events and provide rich, in-depth information on human interactions, relationships, and perspectives. As such, narratives have been used to understand people’s experiences with pain and pain coping mechanisms—as well as to facilitate therapeutic outcomes. Furthermore, narrative research has shown that narration can help restore and promote relief, calm, hope, self-awareness, and self-understanding in chronic pain sufferers. Positive psychology interventions have been successful in improving the lives of people living with chronic pain, but these psychology interventions do not typically incorporate personal narratives. Still, narrative, and positive psychology scholarship foci overlap, as both aim to enhance people’s quality of life, happiness, and well-being, and to promote the understanding of psychosocial strengths and resources. In this article, we provide a rationale for incorporating personal narratives as an agentic form of positive psychology intervention. To that aim, we outline areas of convergence between positive psychology and narrative research and show how combining positive psychology exercises and narration can have additive benefits for pain sufferers. We also show how integrating narration in positive psychology intervention research can have advantages for healthcare research and policy.
... As a consequence, communication between them needs to evolve to meet everyday challenges. For this reason, language underwent multiple stages of complex and dynamic advancements (Dunbar 2017;Morgan et al., 2015), over at least hundreds of thousands of years. In this section, I am interested in presenting its very early stages because they are the hallmark of early human-like thinking (Putt et al. 2017). ...
This work addresses from the perspective of evolutionary pressure, the delicate issue of the mechanisms and causes that are behind the emergence of the faculty of language among early Homo sapiens ancestors. It mainly focuses on the motives or driving forces that are behind the emergence of the first units of language. The latter are defined in this paper, as the first vocal signals that convey information and meanings that go far beyond the usual vocal repertoire of non-human primates. They emerged as a consequence to make a sense to the principle of fairness by probing equal amounts of quantities in the context of food sharing operations after a collaborative labor. Early hominins realized that learning how to make equal food quantities, which should be regarded today as the most fundamental level for doing mathematics, is a prerequisite for the sustainability of collaborative labor (cooperation). This ancestral computing innovation is shown in this paper to be the greatest achievement of evolution in the Homo lineage. By developing the first computational capabilities, early hominins passed successfully the transition that allowed them to move from the instinct driven behavior, which prevails in the animal realm, to reasoning guided behavior in which processing information and language are two fundamental consequences.
... At Qesem cave in modern-day Israel, hominins were roasting and dining on tortoise shells about 400,000 years ago and differential ungulate bone representation in the same layers indicates selective movement of meat-rich body parts to "homebase"-like places equipped with hearths (Stiner et al., 2011). Such places not only promote and intensify social interaction among peers, but they also generate novel contexts for the sharing of experience and what has been referred to as "gossiping" (Dunbar, 2017), and thus ultimately precipitate the evolutionary dynamics between hominin place-making and storytelling resulting in the diagnostic "storied" landscapes documented among contemporary forager groups. Evidence for the emergence of hafted spear tips used for hunting larger animals, although sporadic, also reaches back ca. ...
This paper reconsiders the emergence of language in the hominin lineage from the perspective of general ecology, multispecies theory, phenomenology, and semiotics. We propose that changing communicative environments and their shifting foci of hominin-animal and hominin-hominin interaction are fundamental to understanding the evolution of language in the hominin lineage. After reviewing the available contextual evidence on the nature and transformation of communicative ecologies in the deep-past, we pledge for interpretive conservatism and argue that an "extended short chronology" for the evolution of human language is currently best supported by the archaeological data (in sync with a prolonged period of intensified "indexical" communication). We further propose that this evolutionary trajectory is best understood as a form of non-linear "co-evolution" and hence interlaced with key developments in multiple hominin behavioral arenas and material registers, such as animal relationships, technical behavior, artistic expression and the modalities and scale of social life. Systematically mapping and exploring this broader "general ecology" of communicative needs, concerns, functions, and horizons minimally requires the integration of archaeology, ethology, linguistics, and phenomenology.
... Any youngster far from its mother is vulnerable; grunts and howls would be one way to keep track of stray children. Homo erectus must have needed to vocalise in order to locate, warn, and summon his tribe (Dunbar, 2017), facilitating a versatile, expanded range of vocal sound and volume; this is supported by bony upper spine configurations of early human and Neanderthal fossils, which indicate regular, prolonged, controlled vocal activity (Bayne, 2016;MacWhinney, 2005). ...
This paper presents the argument that inherent musicality in human movement is near-universal. I examine data and empirical evidence which suggest that dance, music, speech, and bipedalism are interrelated characteristics, rooted in the earliest moments of our history. The combination of proto-musical, rhythmic, tonal vocalisation and explanatory gesture has been suggested as the seminal beginning, both of dance and of language. This topic has been vigorously debated, indeed some twentieth-century studies dispute the universality of human musicality. Recent technological advances have, however, revealed data which support the case for innate, universal human musicality. I discuss possible reasons for adaptations for music, dance, and speech, and offer examples from neuroscience of our innate beat perception and entrainment ability, with consequent implications for dance as therapy and rehabilitation.
... real ability to, without technological tools or processing media, address a crowd through sonic projection is an evolutionary feature of human physiology, with the unique vocal apparatus developing in archaic humans through changes in the nervous system, breathing capacity, larynx, and ear canals. While direct social grooming through touch (requiring one-on-one action) took time and delimited social groups, time could be used more effectively with so called "vocal grooming," according to anthropologist and evolutionary psychologist Robin Dunbar (2017), specialized in the bonding processes in mammals. According to him, both laughter -understood as wordless, amusical chorusing which only in humans can consist of an uninterrupted series of exhalations -and later non-verbal singing has been suggested to precede language. ...
How can live-performed chamber operas be conceptualized as immersive games with interactive features? This artistic study has resulted in a system model through which degrees of immersion may be generated and analyzed from physical, social, and psychical stimuli. A differentiation of immersive modes has been made possible by the framing of opera-making as game design. The findings indicate that so-called ludo-immersive opera could be developed into operatic chamber opera play for self-reliant participants, constituting an intimate and alternate practice in which dynamic game-masters may replace supervising directors. However, this practice is entangled with the question of future training for operatic practitioners outside the mainstream opera format, and beyond both Wagnerian and Brechtian spectatorship. The shift from the traditional audience/performer relationship to a novel form of immersive interaction requires a new mind-set and training for opera practitioners, to encourage autonomy and active participation by individual visitors. Theoretically, the study connects recent innovations in opera to the aesthetic principles of the Apollonian and the Dionysian and positions ludo-immersive opera in relation the these. The principles bridge immersion, opera, and game-playing, articulated by a reinterpretation of Roger Caillois’ taxonomy of play. The issue of immersion as an artistic aim in opera is highlighted. Moreover, artists’ and visitors’ reciprocal participation in ludo-immersive opera is discussed in regard to its historical context of operatic event-making and forms of presentation. The project explores the detailed consequences of perception and performance in chamber opera with ludic and immersive features, primarily inspired by live-action role playing. The main objective has been to investigate how operatic events can be presented as immersive adventures rather than spectacles, and consequences that the integration of playing visitors in professional opera implies for artistic practice. In four operas created during the period 2016–2020, interventions and encounters between artists and visitors in musically driven situations framed by fictional settings have been staged and studied. The artistic researcher has iteratively been engaged in action as opera singer, librettist, dramaturge, and director. Data from the research cycles include field recordings from the productions and reports from the participants in the form of interviews and surveys.
... In addition, they are more likely to share resources with a benevolent person than a malevolent one [2,3]. Unfortunately, it is impossible to observe the behavior of every person and learn about his/her personal traits considering the size of human societies [e.g., 4]. Relying on verbal information from others (i.e., testimony) can be beneficial and effective for identifying good people and avoiding the bad [5]. ...
Children can identify who is benevolent or malevolent not only through first-hand experiences and observations but also from the testimony of others. In this study, we investigated whether 5- and 7-year-olds (N = 128) would form their attitudes toward others after hearing testimony about that person’s past moral behavior and whether the valence of testimony would differently influence the children. In the positive condition, half of the participants gained information about three puppets: puppet A’s prosocial behavior by their own first-hand observation, testimony about puppet B’s past prosocial behavior, and testimony about puppet C’s past neutral behavior. In the negative condition, the other half also learned information about the three puppets: puppet A’s antisocial behavior by their own first-hand observation, testimony about puppet B’s past antisocial behavior, and testimony about puppet C’s past neutral behavior. Then they engaged in tasks that measured their behavioral attitudes toward the puppets and evaluated the goodness of each puppet to assess their attitudes at a cognitive level. Our results concluded that the children form their behavioral attitudes toward others based on testimony starting at the age of 7, and attitude formation at the cognitive level based on testimony is seen at age 5. Negative testimony, rather than positive testimony, influences the children’s attitudes toward others. In addition, the 7-year-olds’ use of testimony differs depending whether they are the allocators or the receivers of rewards. Our findings deepen understanding of how children rely on the verbal information around themselves when they navigate interactions with others.
... Dunbar [97] has sought to understand the dynamics of social interaction that supported the development of individual musical ability. He proposes a developmental basis for the universality of music when he suggests that music is a form of 'social grooming'; a necessary enhancement of the primate practice of grooming for social cohesion that developed as proto-human group size grew. ...
Growing international appreciation of the increasing risk posed by natural hazard events acknowledges the effects that climate change and increasingly vulnerable populations will have on future costs and casualties of disasters. As concerns about the impacts of natural hazard events increase, researchers and practitioners are interested in identifying effective processes to build individual and community resilience. To date, despite resources, time and effort being made by governments and NGOs to encourage disaster risk reduction (DRR) programs at national, regional and local levels, most communities remain poorly prepared, and improvements have only been incremental.
One way to gain insight into systems that may improve local community resilience is to examine (rare) examples where communities have avoided the worst impacts of a natural disaster through implementation of recognizable DRR strategies. One example is Simeulue Island in Indonesia. Simeulue was only 43km from the epicenter of the earthquake that initiated the Indian Ocean tsunami in December 2004. The 15m tsunami waves which destroyed all but two of the islands 171 schools, 60 bridges, 41 medical centers and left 85% of the population homeless, but only 7 out of the 80,000 inhabitants died (IsDB and Bank, 2016) [1]. Music and song have been identified as an important part of Simeulue's DRR success (Sutton and et al., 2020; Sutton et al., 2018; Sutton and et al., 2020) [2-4]. This paper discusses the nature of the songs of Simeulue and considers the socio-cognitive processes whereby music was co-opted to entrain risk information about tsunami and their avoidance into the Simeulue community's Sense of Coherence (‘SOC’). The findings indicate that the people of Simeulue applied techniques now understood to optimize learning. While highly effective, they rely on rudimentary human skills and have consequently been overlooked or ignored in most formal DRR contexts.
... Furthermore, it has been suggested that communication and language primarily serve a social purpose (for review see Li & Jeong, 2020) and that language developed in synchrony with social group size and social behavior during human evolution (e.g., Dunbar, 2017;Pinker, 2010). For all these reasons, language cannot easily be disentangled from sociality. ...
Can we predict the future by reading others´ minds? This study explores whether attributing others' personality traits facilitate predictions about their future actions and the temporal order of these future actions. Prior evidence demonstrated that the posterior cerebellar Crus is involved in identifying the temporal sequence of social actions and the person's traits they imply. Based on this, we hypothesized that this area might also be recruited in the reverse process, that is, knowledge of another person's personality traits supports predictions of temporal sequences of others' actions. In this study, participants were informed about the trait of a person, and then had to select actions that were consistent with this information and arrange them in the most likely temporal order. As hypothesized, the posterior cerebellar Crus 1 and 2 were strongly activated when compared to a control task which involved only the selection of actions (without temporal ordering) or which depicted non-social objects and their characteristics. Our findings highlight the important function of the posterior cerebellar Crus in the prediction of social action sequences in social understanding.
... Furthermore, it has been suggested that communication and language primarily serve a social purpose (for review see Li & Jeong, 2020) and that language developed in synchrony with social group size and social behavior during human evolution (e.g., Dunbar, 2017;Pinker, 2010). For all these reasons, language cannot easily be disentangled from sociality. ...
Can we predict the future by reading others´ minds? This study explores whether attributing others' personality traits facilitate predictions about their future actions and the temporal order of these future actions. Prior evidence demonstrated that the posterior cerebellar Crus is involved in identifying the temporal sequence of social actions and the person's traits they imply. Based on this, we hypothesized that this area might also be recruited in the reverse process, that is, knowledge of another person's personality traits supports predictions of temporal sequences of others' actions. In this study, participants were informed about the trait of a person, and then had to select actions that were consistent with this information and arrange them in the most likely temporal order. As hypothesized, the posterior cerebellar Crus 1 and 2 were strongly activated when compared to a control task which involved only the selection of actions (without temporal ordering) or which depicted non-social objects and their characteristics. Our findings highlight the important function of the posterior cerebellar Crus in the prediction of social action sequences in social understanding.
... Stimulation of the skin is probably an important stimulus for those being groomed. In humans, with little body hair to groom, other kinds of touching may stimulate a tactile system that is homologous with other primates (Dunbar 2017). Social and emotional components comparable to those of primates are demonstrated by experiments with humans, including neural differentiation between affective contacts and neutral tactile sensations. ...
... Leavens and colleagues (Leavens et al. 2014) argue that chimpanzees use grooming calls to attract assistance from others when solving novel problems. Dunbar (2017) argues that early hominid grooming behaviors evolved into human language. These ideas motivate a linguistic version of the second rule for humans: if I can't reciprocate with food, then I'll reciprocate with linguistic grooming. ...
I argue that it is rational and appropriate for atheists to give thanks to deep impersonal agents for the benefits they give to us. These agents include our evolving biosphere, the sun, and our finely-tuned universe. Atheists can give thanks to evolution by sacrificially burning works of art. They can give thanks to the sun by performing rituals in solar calendars (like stone circles). They can give thanks to our finely-tuned universe, and to existence itself, by doing science and philosophy. But these linguistic types of thanks-giving are forms of non-theistic contemplative prayer. Since these behaviors resemble ancient pagan behaviors, it is fair to call them pagan. Atheistic paganism may be part of an emerging ecosystem of naturalistic religions.
... Dingle et al. (2013) determined three major outcomes of singing: personal (e.g., emotion regulation and spiritual experience), social (e.g., connectedness with other choir members), and functional (e.g., health benefits) outcomes. It has also been proposed that vocalizing together offers an efficient way to create bonds, which was likely an important adaptive trait for our human ancestors (Dunbar, 2017). Singing can occur in a variety of social contexts, such as amongst sport fans and within military and religious organizations. ...
Singing and chanting are ubiquitous across World cultures. It has been theorized that such practices are an adaptive advantage for humans because they facilitate bonding and cohesion between group members. Investigations into the effects of singing together have so far focused on the physiological effects, such as the synchronization of heart rate variability (HRV), of experienced choir singers. Here, we study whether HRV synchronizes for pairs of non-experts in different vocalizing conditions. Using time-frequency coherence (TFC) analysis, we find that HRV becomes more coupled when people make long (> 10 s) sounds synchronously compared to short sounds (< 1 s) and baseline measurements (p < 0.01). Furthermore, we find that, although most of the effect can be attributed to respiratory sinus arrhythmia, some HRV synchronization persists when the effect of respiration is removed: long notes show higher partial TFC than baseline and breathing (p < 0.05). In addition, we observe that, for most dyads, the frequency of the vocalization onsets matches that of the peaks in the TFC spectra, even though these frequencies are above the typical range of 0.04–0.4 Hz. A clear correspondence between high HRV coupling and the subjective experience of “togetherness" was not found. These results suggest that since autonomic physiological entrainment is observed for non-expert singing, it may be exploited as part of interventions in music therapy or social prescription programs for the general population.
... Under the basic assumption that humans are a social species which have an increased communication level, and that language developed as a social and cultural tool to facilitate this interaction (Dunbar, 2017;Pinker & Jackendoff, 2005;Tomasello, Call, & Hare, 2003), it is plausible that the presence of another person could noticeably impact language processing. Indeed, social information and social context appear of the highest relevance in language processes (Bara, Enrici, & Adenzato, 2016;Barr & Keysar, 2006;Brown-Schmidt & Heller, 2018;Hasson, Egidi, Marelli, & Willems, 2018;Pulvermü ller & Fadiga, 2016). ...
Although, evolutionarily, language emerged predominantly for social purposes, much has yet to be uncovered regarding how language processing is affected by social context. Social presence research studies the ways in which the presence of a conspecific affects processing, but has yet to be thoroughly applied to language processes. The principal aim of this study was to see how syntactic and semantic language processing might be subject to mere social presence effects by studying Event-Related brain Potentials (ERP). In a sentence correctness task, participants read sentences with a semantic or syntactic anomaly while being either alone or in the mere presence of a confederate. Compared to the alone condition, the presence condition was associated with an enhanced N400 component and a more centro-posterior LAN component (interpreted as an N400). The results seem to imply a boosting of heuristic language processing strategies, proper of lexico-semantic operations, which actually entails a shift in the strategy to process morphosyntactic violations, typically based on algorithmic or rule-based strategies. The effects cannot be related to increased arousal levels. The apparent enhancement of the activity in the precuneus while in presence of another person suggests that the effects conceivably relate to social cognitive and attentional factors. The present results suggest that understanding language comprehension would not be complete without considering the impact of social presence effects, inherent to the most natural and fundamental communicative scenarios.
... When attempting to track the evolution of human language by means of comparative assays, it is further worth noting that the parallel nonhuman trait, the candidate of comparison, might not be so straightforward because human language definition varies from that of mere cognitive ability (Berwick et al., 2013;Bolhuis, Tattersall, Chomsky, & Berwick, 2014) to that of a communication vehicle (Corballis, 2016). The vast majority of references to language-like nonhuman abilities (or disabilities), however, come from animal communication studies, and although an entire research field focuses on body-gestural communication (especially in primates, e.g., Arbib, 2005;Corballis, 2002;Hewes et al., 1973;Tomasello, 2008), most comparisons deal with parallels between human speech and other animals' vocal behavior (Berwick, Okanoya, Beckers, & Bolhuis, 2011;Dunbar, 2017;Fitch, 2000;Manser, Seyfarth, & Cheney, 2002;Petkov & Jarvis, 2012;Prat, Taub, & Yovel, 2016;Scharff & Petri, 2011;Schel, Townsend, Machanda, Zuberbühler, & Slocombe, 2013;Seyfarth & Cheney, 2003;Seyfarth, Cheney, & Marler, 1980;Slocombe & Zuberbühler, 2005). These comparisons essentially put us in the Martian's shoes. ...
Language is a cornerstone of human culture, yet the evolution of this cognitive-demanding ability is shrouded in mystery. Studying how different species demonstrate this trait can provide clues for its evolutionary route. Indeed, recent decades saw ample scientific attempts to compare human speech, the prominent behavioral manifestation of language, with other animals’ vocalizations. Diligent studies have found only elementary parallels to speech in other animals, fortifying the belief that language is uniquely human. But have we really tested this uniqueness claim? Surprisingly, a true impartial comparison between human speech and other animals’ vocalizations has hardly ever been conducted. Here, I illustrate how treating humans as an equal species in vocal-communication research is expected to provide us with no evidence for human superiority in this realm. Thus, novel balanced and unbiased comparative studies are vital for identifying any unique component of human speech and language.
... Language is commonly thought of as a culturally evolved system of communication (Dunbar, 1996(Dunbar, , 2017Tomasello, 2003Tomasello, , 2008Kirby et al., 2007;Smith and Kirby, 2008;Chater and Christiansen, 2010;Kirby, 2017) rather than a computational system for generating linguistic objects expressive of thought (Chomsky, 2010(Chomsky, , 2013(Chomsky, , 2017a. Furthermore, it is also commonly argued that language has gradually evolved from finite proto-language which eventually developed into infinite language of modern humans (Bickerton, 1990;Pinker and Bloom, 1990;Corballis, 2002;Fitch, 2010;Jackendoff, 2010;Dediu and Levinson, 2013;Christiansen and Chater, 2015;Jackendoff and Wittenberg, 2017). ...
Language is commonly thought of as a culturally evolved system of communication rather than a computational system for generating linguistic objects that express thought. Furthermore, language is commonly argued to have gradually evolved from finite proto-language which eventually developed into infinite language of modern humans. Both ideas are typically integrated in accounts that attempt to explain gradual evolution of more complex language from the increasingly strong pressures of communicative needs. Recently some arguments have been presented that the probability of the emergence of infinitely productive languages is increased by communicative pressures. These arguments fail. The question whether decidable languages evolve into infinite language is vacuous since infinite generation is the null hypothesis for a generative procedure. The argument that increasing cardinality leads to infinite language is incoherent since it essentially conflates concepts of performance with notions of competence. Recursive characterization of infinite language is perfectly consistent with finite output. Further, the discussion completely ignores a basic insight that language is not about decidability of weakly generated strings but rather about properties of strongly generated structures. Finally, the plausibility proof that infinite productivity evolves from finite language is false because it confuses (infinite) cardinal numbers with (natural) ordinal numbers. Infinite generation cannot be reached with a stepwise approach.
... In multiple disciplines of natural sciences spanning from zoology, psycholog, to economy [11,17,45], one of the most fundamental thus important collective behaviors to study is: grouping -a population of units aggregate together for collective decision-making. Grouping is believed to imply the emergence of sociality and to induce other collective behaviors [21]. ...
We conduct an empirical study on discovering the ordered collective dynamics obtained by a population of intelligence agents, driven by million-agent reinforcement learning. Our intention is to put intelligent agents into a simulated natural context and verify if the principles developed in the real world could also be used in understanding an artificially-created intelligent population. To achieve this, we simulate a large-scale predator-prey world, where the laws of the world are designed by only the findings or logical equivalence that have been discovered in nature. We endow the agents with the intelligence based on deep reinforcement learning (DRL). In order to scale the population size up to millions agents, a large-scale DRL training platform with redesigned experience buffer is proposed. Our results show that the population dynamics of AI agents, driven only by each agent's individual self-interest, reveals an ordered pattern that is similar to the Lotka-Volterra model studied in population biology. We further discover the emergent behaviors of collective adaptations in studying how the agents' grouping behaviors will change with the environmental resources. Both of the two findings could be explained by the self-organization theory in nature.
... Humans are special. They have a special kind of language and cognize particularly efficiently in cooperative and meaningful social interaction (Dunbar, 1993(Dunbar, , 2016Tomasello, 2008Tomasello, , 2014. Animal communication systems seem more restricted, although some species show surprising abilities to process structurally rich strings (Abe and Watanabe, 2011;Gentner et al., 2006). ...
Neurocognitive and neurolinguistics theories make explicit statements relating specialized cognitive and linguistic processes to specific brain loci. These linking hypotheses are in need of neurobiological explanation. Recent mathematical models of human language mechanisms constrained by fundamental neuroscience principles and established knowledge about comparative neuroanatomy offer explanations for where, when and how language is processed in the human brain. In these models, network structure and connectivity along with action- and perception-induced correlation of neuronal activity co-determine neurocognitive mechanisms. Language learning leads to the formation of action perception circuits (APCs) with specific distributions across cortical areas. Cognitive and linguistic processes such as speech production, comprehension, verbal working memory and prediction are modelled by activity dynamics in these APCs, and combinatorial and communicative-interactive knowledge is organized in the dynamics within, and connections between APCs. The network models and, in particular, the concept of distributionally-specific circuits, can account for some previously not well understood facts about the cortical ‘hubs’ for semantic processing and the motor system’s role in language understanding and speech sound recognition. A review of experimental data evaluates predictions of the APC model and alternative theories, also providing detailed discussion of some seemingly contradictory findings. Throughout, recent disputes about the role of mirror neurons and grounded cognition in language and communication are assessed critically.
... Language serves essentially social and interactive functions (e.g. Dunbar, 2017;Donald, 2017). Pragmatic perspectives on language have become increasingly salient in language evolution research (e.g., Scott-Phillipps, 2015). ...
Gaze direction and pupil dilation play a critical role in communication and social interaction due to their ability to redirect and capture our attention and relevance for emotional information. The present study aimed to explore whether the pupil size and the gaze direction of the speaker affect language comprehension. Participants listened to sentences that could be correct or contain a syntactic anomaly, while the static face of a speaker was manipulated in terms of gaze direction (direct, averted) and pupil size (mydriasis, miosis). Left anterior negativity (LAN) and P600 linguistic ERP components were observed to syntactic anomalies for all conditions. The speaker’s gaze did not impact syntactic comprehension. However, the amplitude of the LAN component for mydriasis (dilated pupil) was larger than for miosis (constricted pupil) condition. Larger pupils are generally associated with care, trust, interest, and attention, which might facilitate syntactic processing at early automatic stages. The result also supports the permeable and context-dependent nature of syntax. Previous studies also support an automatic nature of syntax (fast and efficient), which combined with the permeability to relevant sources of communicative information, such as pupil size and emotions, is highly adaptive for language comprehension and social interaction.
This chapter reviews some of the more important scenarios for language evolution, including Bickerton’s “power scavenging” hypothesis and Chomsky’s “Merge” hypothesis, all of which attempt to theorize the emergence of the earliest “proto-words” and “proto-signs,” the potentially multiple communicative variants using speech and/or gestures that may have been developed by the small, scattered human groups existing long before any known proto-language became dominant enough to leave traces in modern language.
This is a book about numbers – what they are as concepts and how and why they originate – as viewed through the material devices used to represent and manipulate them. Fingers, tallies, tokens, and written notations, invented in both ancestral and contemporary societies, explain what numbers are, why they are the way they are, and how we get them. Overmann is the first to explore how material devices contribute to numerical thinking, initially by helping us to visualize and manipulate the perceptual experience of quantity that we share with other species. She explores how and why numbers are conceptualized and then elaborated, as well as the central role that material objects play in both processes. Overmann's volume thus offers a view of numerical cognition that is based on an alternative set of assumptions about numbers, their material component, and the nature of the human mind and thinking.
Malešević offers a novel sociological answer to the age-old question: 'Why do humans fight?'. Instead of focusing on the motivations of solitary individuals, he emphasises the centrality of the social and historical contexts that make fighting possible. He argues that fighting is not an individual attribute, but a social phenomenon shaped by one's relationships with other people. Drawing on recent scholarship across a variety of academic disciplines as well as his own interviews with the former combatants, Malešević shows that one's willingness to fight is a contextual phenomenon shaped by specific ideological and organisational logic. This book explores the role biology, psychology, economics, ideology, and coercion play in one's experience of fighting, emphasising the cultural and historical variability of combativeness. By drawing from numerous historical and contemporary examples from all over the world, Malešević demonstrates how social pugnacity is a relational and contextual phenomenon that possesses autonomous features.
"Did you know the most dominant apes and monkeys are usually the kindest? They share the most food, groom others more often, break up fights, are slow to anger, and breathe in a relaxed manner. Those on the bottom of the social hierarchy are the opposite. They are stingy, combative, irritable, anxious, depressed, and they breathe shallowly. It is not easy for a submissive primate to become dominant. They have mindsets, mannerisms, and muscle tension that keep them from escaping their subordinate social strategy and the chronic stress it produces.
All of this generalizes to people. If you want to be free of negative emotion, you need to rehabilitate physical trauma in your breath, eyes, face, voice, heart, gut, spine, and brain. Program Peace will coach you to do precisely this by first retraining your breathing pattern, and then walking you through dozens of innovative and effective self-care exercises. After creating new mindsets and mannerisms, and learning to reinvigorate muscles you never knew you had, you will find yourself more confident, healthier, kinder, and reprogrammed for peace."
The social complexity hypothesis (SCH) for communication states that the range and frequency of social interactions drive the evolution of complex communication systems. Surprisingly, few studies have empirically tested the SHC for vocal communication systems. Filling this gap is important because a co-evolutionary runaway process between social and vocal complexity may have shaped the most intricate communication system, human language. We here propose the African elephant Loxodonta spec. as an excellent study system to investigate the relationships between social and vocal complexity. We review how the distinct differences in social complexity between the two species of African elephants, the forest elephant L. cyclotis and the savanna elephant L. africana, relate to repertoire size and structure, as well as complex communication skills in the two species, such as call combination or intentional formant modulation including the trunk. Our findings suggest that Loxodonta may contradict the SCH, as well as other factors put forth to explain patterns of vocal complexity across species. We propose that life history traits, a factor that has gained little attention as a driver of vocal complexity, and the extensive parental care associated with a uniquely low and slow reproductive rate, may have led to the emergence of pronounced vocal complexity in the forest elephant despite their less complex social system compared to the savanna elephant. Conclusions must be drawn cautiously, however. A better understanding of vocal complexity in the genus Loxodonta will depend on continuing advancements in remote data collection technologies to overcome the challenges of observing forest elephants in their dense rainforest habitat, as well as the availability of directly comparable data and methods, quantifying both structural and contextual variability in the production of rumbles and other vocalizations in both species of African elephants.
The aim of this paper is to review recent hypotheses on the evolutionary origins of music in Homo sapiens , taking into account the most influential traditional hypotheses. To date, theories derived from evolution have focused primarily on the importance that music carries in solving detailed adaptive problems. The three most influential theoretical concepts have described the evolution of human music in terms of 1) sexual selection, 2) the formation of social bonds, or treated it 3) as a byproduct. According to recent proposals, traditional hypotheses are flawed or insufficient in fully explaining the complexity of music in Homo sapiens . This paper will critically discuss three traditional hypotheses of music evolution (music as an effect of sexual selection, a mechanism of social bonding, and a byproduct), as well as and two recent concepts of music evolution - music as a credible signal and Music and Social Bonding (MSB) hypothesis.
Although laughter is probably of deep evolutionary origin, the telling of jokes, being language-based, is likely to be of more recent origin within the human lineage. In language-based communication, speaker and listener are engaged in a process of mutually understanding each other's intentions (mindstates), with a conversation minimally requiring three orders of intentionality. Mentalizing is cognitively more demanding than non-mentalizing cognition, and there is a well-attested limit at five orders in the levels of intentionality at which normal adult humans can work. Verbal jokes commonly involve commentary on the mindstates of third parties, and each such mindstate adds an additional level of intentionality and its corresponding cognitive load. We determined the number of mentalizing levels in a sample of jokes told by well-known professional comedians and show that most jokes involve either three or five orders of intentionality on the part of the comedian, depending on whether or not the joke involves other individuals' mindstates. Within this limit there is a positive correlation between increasing levels of intentionality and subjective ratings of how funny the jokes are. The quality of jokes appears to peak when they include five or six levels of intentionality, which suggests that audiences appreciate higher mentalizing complexity whilst working within their natural cognitive constraints.
It has been proposed that singing evolved to facilitate social cohesion. However, it remains unclear whether bonding arises out of properties intrinsic to singing or whether any social engagement can have a similar effect. Furthermore, previous research has used one-off singing sessions without exploring the emergence of social bonding over time. In this semi-naturalistic study, we followed newly formed singing and non-singing (crafts or creative writing) adult education classes over seven months. Participants rated their closeness to their group and their affect, and were given a proxy measure of endorphin release, before and after their class, at three timepoints (months 1, 3 and 7). We show that although singers and non-singers felt equally connected by timepoint 3, singers experienced much faster bonding: singers demonstrated a significantly greater increase in closeness at timepoint 1, but the more gradual increase shown by non-singers caught up over time. This represents the first evidence for an 'ice-breaker effect' of singing in promoting fast cohesion between unfamiliar individuals, which bypasses the need for personal knowledge of group members gained through prolonged interaction. We argue that singing may have evolved to quickly bond large human groups of relative strangers, potentially through encouraging willingness to coordinate by enhancing positive affect.
Significance
Touch is a powerful tool for communicating positive emotions. However, it has remained unknown to what extent social touch would maintain and establish social bonds. We asked a total of 1,368 people from five countries to reveal, using an Internet-based topographical self-reporting tool, those parts of their body that they would allow relatives, friends, and strangers to touch. These body regions formed relationship-specific maps in which the total area was directly related to the strength of the emotional bond between the participant and the touching person. Cultural influences were minor. We suggest that these relation-specific bodily patterns of social touch constitute an important mechanism supporting the maintenance of human social bonds.
Homophily, the tendency for individuals to associate with those who are most similar to them, has been well documented. However, the influence of different kinds of similarity (e.g. relating to age, music taste, ethical views) in initial preferences for a stranger have not been compared. In the current study, we test for a relationship between sharing a variety of traits (i.e. having different kinds of similarity) with a stranger and the perceived likeability of that stranger. In two online experiments, participants were introduced to a series of virtual partners with whom they shared traits, and subsequently carried out activities designed to measure positivity directed towards those partners. Greater numbers of shared traits led to linearly increasing ratings of partner likeability and ratings on the Inclusion of Other in Self scale. We identified several consistent predictors of these two measures: shared taste in music, religion and ethical views. These kinds of trait are likely to be judged as correlates of personality or social group, and may therefore be used as proxies of more in-depth information about a person who might be socially more relevant.
Significance
Control of fire and the capacity for cooking led to major anatomical and residential changes for early humans, starting more than a million years ago. However, little is known about what transpired when the day was extended by firelight. Data from the Ju/’hoan hunter-gatherers of southern Africa show major differences between day and night talk. Day talk centered on practicalities and sanctioning gossip; firelit activities centered on conversations that evoked the imagination, helped people remember and understand others in their external networks, healed rifts of the day, and conveyed information about cultural institutions that generate regularity of behavior and corresponding trust. Appetites for firelit settings for intimate conversations and for evening stories remain with us today.
Fire and conversation are two things that have been of crucial importance for our evolutionary story, yet they have received only rather casual attention. Yes, we know that fire was used for cooking (probably casually at first, but later as a matter of regularity), and, yes, we know that language evolved at some point and has been important for human culture. However, there has been a longstanding tendency to take these two phenomena for granted as something self-evidently useful and hence presumably of ancient origin. In PNAS, Wiessner (1) brings these two phenomena together in a way that has significant implications for our understanding of both why they evolved and when they did so. In the first such study of its kind, she recorded the topics of conversation during the day and around the campfire at night among a group of Ju’/hoansi (or !Kung) Bushman in Botswana, a people whose living hunter-gatherer ecology is similar to that which characterized most of our evolutionary history. In this sample, most daytime conversations were functional (discussions of land rights, economic matters, norm regulation), but most evening conversations were social (more than 80% were stories). Stories are important in all societies because they provide the framework that holds the community together: we share this a set of cultural knowledge because we are who we are, and that is why we are different from the folks that live over the hill.
Homophily, the tendency for people to cluster with similar others, has primarily been studied in terms of proximal, psychological causes, such as a tendency to have positive associations with people who share traits with us. Here we investigate whether homophily could be correlated with perceived group membership, given that sharing traits with other people might signify membership of a specific community. In order to investigate this, we tested whether the amount of homophily that occurs between strangers is dependent on the number of people they believe share the common trait (i.e. the size of group that the trait identifies). In two experiments, we show that more exclusive (smaller) groups evoke more positive ratings of the likeability of a stranger. When groups appear to be too inclusive (i.e. large) homophily no longer occurs, suggesting that it is not only positive associations with a trait that cause homophily, but a sense of the exclusiveness of a group is also important. These results suggest that group membership based on a variety of traits can encourage cohesion between people from diverse backgrounds, and may be a useful tool in overcoming differences between groups.
The picture of human evolution has been transformed by new evidence in recent years, but contributing disciplines seem to have difficulty in sharing knowledge on a common basis. The disciplines producing primary data in paleoanthropology scarcely reach out to a broader picture and are often bypassed by writers in other disciplines. Archaeology is encouraged by its material evidence to project a view that “what you see is what there was”: by definition, there can be only a late flowering of human abilities. Yet there is a vital alternative paleontological record of the early hominins that gives us important information about their brains and suggests that brains become large and complex far earlier than that late material complexity might imply. How, then, to account for the large brains acting far back in time? Evolutionary psychology, in the form of the social brain hypothesis, claims that these large brains were concerned with managing a far-reaching social life. In becoming human, those brains did not merely become larger, but of necessity they took on new socialized perspectives, a domestication of emotional capacities allowing greater insights and collaboration. We argue that there is at least a 2-million-year social record that must be made part of mainstream interpretation.
Cooperation requires that individuals are able to identify, and preferentially associate with, others who have compatible preferences and the shared background knowledge needed to solve interpersonal coordination problems. This body of shared knowledge constitute a substantial proportion of what is called ‘culture’. It has been argued that, for this reason, individuals prefer to associate with others who share their culture, and also that shared appreciation of humor provides a particularly effective means of identifying others with the relevant preferences and knowledge. The present experiment uses a ‘dummy rating procedure’ to compare the effects of sharing an appreciation of non-humorous (first lines of novels) and humorous (jokes) cultural stimuli on interpersonal affiliation, altruism and assessment. The results show that the degree of shared appreciation for both sets of stimuli had a positive effect on Affiliation; only humorous stimuli had an effect on Altruism; and neither effected the Assessment of others' personal traits. Thus, the results support the general theory that shared culture promotes affiliation, and provide evidence of the special role of humor in interpersonal relations.
Cooperation requires that individuals are able to identify, and preferentially associate with, others who have compatible preferences and the shared background knowledge needed to solve interpersonal coordination problems. The present study investigates the nature of such similarity within social networks, asking: What do friends have in common? And what is the relationship between similarity and altruism? The results show that similarity declines with frequency of contact; similarity in general is a significant predictor of altruism and emotional closeness; and, specifically, sharing a sense of humor, hobbies and interests, moral beliefs, and being from the same area are the best predictors. These results shed light on the structure of relationships within networks and provide a possible checklist for predicting attitudes toward strangers, and in-group identification.
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The origin of human language, and in particular the question of whether or not Neanderthal man was capable of language/speech, is of major interest to anthropologists but remains an area of great controversy. Despite palaeoneurological evidence to the contrary, many researchers hold to the view that Neanderthals were incapable of language/speech, basing their arguments largely on studies of laryngeal/basicranial morphology. Studies, however, have been hampered by the absence of unambiguous fossil evidence. We now report the discovery of a well-preserved human hyoid bone from Middle Palaeolithic layers of Kebara Cave, Mount Carmel, Israel, dating from about 60,000 years BP. The bone is almost identical in size and shape to the hyoid of present-day populations, suggesting that there has been little or no change in the visceral skeleton (including the hyoid, middle ear ossicles, and inferentially the larynx) during the past 60,000 years of human evolution. We conclude that the morphological basis for human speech capability appears to have been fully developed during the Middle Palaeolithic.
Frequencies of social grooming recorded from 44 species of free-living primates correlate with group size but not body size. This is interpreted as evidence for the social function of grooming and against the purely hygienic function. However, there is some evidence to suggest that body size is a more important determinant of grooming time among platyrrhine primates. This might imply that there has been a shift in the functional system governing grooming during primate evolution.
Primate societies are characterized by bonded social relationships of a kind that are rare in other mammal taxa. These bonded relationships, which provide the basis for coalitions, are underpinned by an endorphin mechanism mediated by social grooming. However, bonded relationships of this kind impose constraints on the size of social groups that are possible. When ecological pressures have demanded larger groups, primates have had to evolve new mechanisms to facilitate bonding. This has involved increasing the size of vocal and visual communication repertoires, increasing the time devoted to social interaction and developing a capacity to manage two-tier social relationships (strong and weak ties). I consider the implications of these constraints for the evolution of human social communities and argue that laughter was an early evolutionary innovation that helped bridge the bonding gap between the group sizes characteristic of chimpanzees and australopithecines and those in later hominins.
Although laughter forms an important part of human non-verbal communication, it has received rather less attention than it deserves in both the experimental and the observational literatures. Relaxed social (Duchenne) laughter is associated with feelings of wellbeing and heightened affect, a proximate explanation for which might be the release of endorphins. We tested this hypothesis in a series of six experimental studies in both the laboratory (watching videos) and naturalistic contexts (watching stage performances), using change in pain threshold as an assay for endorphin release. The results show that pain thresholds are significantly higher after laughter than in the control condition. This pain-tolerance effect is due to laughter itself and not simply due to a change in positive affect. We suggest that laughter, through an endorphin-mediated opiate effect, may play a crucial role in social bonding.
The timing of the human control of fire is a hotly debated issue, with claims for regular fire use by early hominins in Africa at ∼ 1.6 million y ago. These claims are not uncontested, but most archaeologists would agree that the colonization of areas outside Africa, especially of regions such as Europe where temperatures at time dropped below freezing, was indeed tied to the use of fire. Our review of the European evidence suggests that early hominins moved into northern latitudes without the habitual use of fire. It was only much later, from ∼ 300,000 to 400,000 y ago onward, that fire became a significant part of the hominin technological repertoire. It is also from the second half of the Middle Pleistocene onward that we can observe spectacular cases of Neandertal pyrotechnological knowledge in the production of hafting materials. The increase in the number of sites with good evidence of fire throughout the Late Pleistocene shows that European Neandertals had fire management not unlike that documented for Upper Paleolithic groups.
Cooking is a human universal that must have had widespread effects on the nutrition, ecology, and social relationships of the species that invented it. The location and timing of its origins are unknown, but it should have left strong signals in the fossil record. We suggest that such signals are detectable at ca. 1.9 million years ago in the reduced digestive effort (e.g., smaller teeth) and increased supply of food energy (e.g., larger female body mass) of early Homo erectus. The adoption of cooking required delay of the consumption of food while it was accumulated and/or brought to a processing area, and accumulations of food were valuable and stealable. Dominant (e.g., larger) individuals (typically male) were therefore able to scrounge from subordinate (e.g., smaller) individuals (typically female) instead of relying on their own foraging efforts. Because female fitness is limited by access to resources (particularly energetic resources), this dynamic would have favored females able to minimize losses to theft. To do so, we suggest, females formed protective relationships with male co-defenders. Males would have varied in their ability or willingness to engage effectively in this relationship, so females would have competed for the best food guards, partly by extending their period of sexual attractiveness. This would have increased the numbers of matings per pregnancy, reducing the intensity of male intrasexual competition. Consequently, there was reduced selection for males to be relatively large. This scenario is supported by the fossil record, which indicates that the relative body size of males fell only once in hominid evolution, around the time when H. erectus evolved. Therefore we suggest that cooking was responsible for the evolution of the unusual human social system in which pair bonds are embedded within multifemale, multimale communities and supported by strong mutual and frequently conflicting sexual interest.
Human hearing differs from that of chimpanzees and most other anthropoids in maintaining a relatively high sensitivity from 2 kHz up to 4 kHz, a region that contains relevant acoustic information in spoken language. Knowledge of the auditory capacities in human fossil ancestors could greatly enhance the understanding of when this human pattern emerged during the course of our evolutionary history. Here we use a comprehensive physical model to analyze the influence of skeletal structures on the acoustic filtering of the outer and middle ears in five fossil human specimens from the Middle Pleistocene site of the Sima de los Huesos in the Sierra de Atapuerca of Spain. Our results show that the skeletal anatomy in these hominids is compatible with a human-like pattern of sound power transmission through the outer and middle ear at frequencies up to 5 kHz, suggesting that they already had auditory capacities similar to those of living humans in this frequency range.
Singing together seems to facilitate social bonding, but it is unclear whether this is true in all contexts. Here we examine the social bonding outcomes of naturalistic singing behaviour in a European university Fraternity composed of exclusive “Cliques”: recognised sub-groups of 5–20 friends who adopt a special name and identity. Singing occurs frequently in this Fraternity, both “competitively” (contests between Cliques) and “cooperatively” (multiple Cliques singing together). Both situations were recreated experimentally in order to explore how competitive and cooperative singing affects feelings of closeness towards others. Participants were assigned to teams of four and were asked to sing together with another team either from the same Clique or from a different Clique. Participants (N = 88) felt significantly closer to teams from different Cliques after singing with them compared to before, regardless of whether they cooperated with (singing loudly together) or competed against (trying to singing louder than) the other team. In contrast, participants reported reduced closeness with other teams from their own Clique after competing with them. These results indicate that group singing can increase closeness to less familiar individuals regardless of whether they share a common motivation, but that singing competitively may reduce closeness within a very tight-knit group.
This chapter has three main objectives. First, it briefly summarizes the reasons why language might have evolved, and what we are to make of these. It then considers what this has to tell us about why only the hominin lineage evolved the capacity for language. Finally, it revisits the author's previous analyses (Aiello and Dunbar 1993) on the timing of language evolution in the hominin fossil record using new estimates for all the equations involved, in order to explore the sequence by which language might have evolved, and the transitional states involved.
Over our evolutionary history, humans have faced the problem of how to create and maintain social bonds in progressively larger groups compared to those of our primate ancestors. Evidence from historical and anthropological records suggests that group music-making might act as a mechanism by which this large-scale social bonding could occur. While previous research has shown effects of music making on social bonds in small group contexts, the question of whether this effect ‘scales up’ to larger groups is particularly important when considering the potential role of music for large-scale social bonding. The current study recruited individuals from a community choir that met in both small (n = 20–80) and large (a ‘megachoir’ combining individuals from the smaller subchoirs n = 232) group contexts. Participants gave self-report measures of social bonding and had pain threshold measurements taken (as a proxy for endorphin release) before and after 90 min of singing. Results showed that feelings of inclusion, connectivity, positive affect, and measures of endorphin release all increased across singing rehearsals and that the influence of group singing was comparable for pain thresholds in the large versus small group context. Levels of social closeness were found to be greater at pre- and post-levels for the small choir condition. However, the large choir condition experienced a greater change in social closeness as compared to the small condition. The finding that singing together fosters social closeness – even in large group contexts where individuals are not known to each other – is consistent with evolutionary accounts that emphasize the role of music in social bonding, particularly in the context of creating larger cohesive groups than other primates are able to manage.
Conventional wisdom over the past 160 years in the cognitive and neurosciences has assumed that brains evolved to process factual information about the world. Most attention has therefore been focused on such features as pattern recognition, color vision, and speech perception. By extension, it was assumed that brains evolved to deal with essentially ecological problem-solving tasks. 1.
Laughter is a universally produced vocal signal that plays an important role in human social interaction. Researchers have distinguished between spontaneous and volitional laughter, but no empirical work has explored possible acoustic and perceptual differences. If spontaneous laughter is an honest signal of cooperative intent (e.g., derived from play breathing patterns), then the ability to mimic these sounds volitionally could have shaped perceptual systems to be attuned to aspects of spontaneous laughs that are harder to fake—features associated with phylogenetically older vocal control systems. We extracted spontaneous laughs from conversations between friends and volitional laughs elicited by instruction without other provocation. In three perception experiments we found that, 1) participants could distinguish between spontaneous and volitional laughter, 2) when laugh speed was increased (duration decreased 33% and pitch held constant), all laughs were judged as more “real,” with judgment accuracy increasing for spontaneous laughter and decreasing for volitional laughter, and 3) when the laughs were slowed down (duration increased 260% and pitch altered proportionally), participants could not distinguish spontaneous laughs from nonhuman vocalizations but could identify volitional laughs as human-made. These findings and acoustic data suggest that spontaneous and volitional laughs are produced by different vocal systems, and that spontaneous laughter might share features with nonhuman animal vocalizations that volitional laughter does not.
Grueter et al. have recently claimed that grooming time in primates is best explained by terrestriality, which they take to be a proxy for hygiene demand. We suggest that their results arise from a confound between terrestriality and other aspects of sociality, combined with a number of conceptual and sampling problems.
Recent studies suggest that laughter plays an important role in social bonding. Human communities are much larger than those of other primates and hence require more time to be devoted to social maintenance activities. Yet, there is an upper limit on the amount of time that can be dedicated to social demands, and, in nonhuman primates, this sets an upper limit on social group size. It has been suggested that laughter provides the additional bonding capacity in humans by allowing an increase in the size of the “grooming group.” In this study of freely forming laughter groups, we show that laughter allows a threefold increase in the number of bonds that can be “groomed” at the same time. This would enable a very significant increase in the size of community that could be bonded.
In the current resurgence of interest in the biological basis of animal behavior and social organization, the ideas and questions pursued by Charles Darwin remain fresh and insightful. This is especially true of The Descent of Man and Selection in Relation to Sex, Darwin's second most important work. This edition is a facsimile reprint of the first printing of the first edition (1871), not previously available in paperback. The work is divided into two parts. Part One marshals behavioral and morphological evidence to argue that humans evolved from other animals. Darwin shoes that human mental and emotional capacities, far from making human beings unique, are evidence of an animal origin and evolutionary development. Part Two is an extended discussion of the differences between the sexes of many species and how they arose as a result of selection. Here Darwin lays the foundation for much contemporary research by arguing that many characteristics of animals have evolved not in response to the selective pressures exerted by their physical and biological environment, but rather to confer an advantage in sexual competition. These two themes are drawn together in two final chapters on the role of sexual selection in humans. In their Introduction, Professors Bonner and May discuss the place of The Descent in its own time and relation to current work in biology and other disciplines.
The psychology of close human relationships is increasingly well understood and our understanding of the neurobiology of the onset of pairbonding behaviour in a range of species has benefited from the use of rodent-based models. However, the human literature has suffered from a lack of focus upon the unique nature of primate social bonds and has so far failed to adequately identify the neurobiological and behavioural mechanisms which maintain these complex, diverse and enduring social networks. One neurobiological mechanism that has been overlooked is the endogenous opioid system. Though less explicitly researched than the more familiar oxytocin/vasopressin system, there is considerable evidence that the opioids play a fundamental role in sociality, especially in the primates. This review summarises our current understanding of the evidence for the role of this system in prosocial behaviour in non-primate mammals, nonhuman primates and humans. An important conclusion is that the opioid system may play a more central role in sociality in primates (including humans) than in other mammalian taxa.
6 Initial receipt 2 February 2010; final revision received 24 August 2010 7 Abstract 8 Evolutionary theory predicts that kin relations will be distinct from friendships, but recent studies have suggested a degree of similarity 9 between these two types of relationships. In this longitudinal study, we examined the influence of kinship on the maintenance costs of social 10 relationships. We followed 25 students over an 18-month period as they made the transition from school to university and examined the 11 association between kinship, relationship maintenance and decay. The emotional intensity of friendships, in comparison to kin relations, was 12 more sensitive to decreases in contact frequency and more sensitive to decreases in the number of activities done together. These results 13 demonstrate that important differences between kin relations and friendships emerge when the relationships are considered longitudinally and 14 suggest that the costs of maintaining friendships are much higher than the costs of maintaining kin relations.
The propabilities of laughing, smiling, or talking during a given hour and in various social environments were investigated by having undergraduate college students record their performance of these activitics in a log book during a one-week period. All three activities were least likely to occur during the hours immediately before bedtime and after waking and were most frequent in social situations. Smiles and laughs, like talking, were performed primarily during social encounters and were often part of verbal and nonverbal conversations. Because laughing and smiling are phasic social acts, they are of limited value as indices of ongoing (tonic) emotional state. The role of laughing, smiling, and talking in communication, the production of mood, and social bonding is considered.
This study examines the behavioural consequences of the silent bared teeth display (SBT) and the relaxed open mouth display (ROM) in the chimpanzee, and discusses functional similarities with smiling and laughing (respectively) in humans. Rates of affinitive behaviour increase (in relation to baseline levels) following SBT, suggesting that SBT is a signal of affinity. ROM is observed primarily during play, and dyadic play bouts are significantly longer when ROM is bidirectional, indicating that it may be a signal of play. Rates of affinitive behaviour also increased after ROM, suggesting that both displays may have a similar ultimate (evolutionary) function – social bonding; this could explain convergence of the two displays in humans.
Dominance relations among free-living female gelada baboons (Theropithecus gelada) are shown to depend on the individual's aggressiveness, modified by coalitionary support from female relatives. Relatives rank adjacent to each other more of often than expected by chance.
Females are more willing both to give coalitionary support and to do so on an asymmetric basis to females with whom they interact socially (usually relatives) than to those with whom they rarely interact.
The number of offspring that a female has is shown to be a function of her dominance rank. This phenomenon is probably due to the fact that females harass individuals subordinate to them when the latter are in oestrus. It is suggested that the stress caused by this harassment appears to disrupt the female's reproductive physiology, thereby inducing a high rate of anovulatory cycles and amenorrhea. In consequence, subordinate females take longer to conceive than do dominants.
Simulation is used to show that females who form coalitions gain a life-time reproductive advantage over those who do not because coalitions with younger females help to prevent the decline in rank that would otherwise occur in old age.
It is argued that females prefer to form coalitions with caughters rather than unrelated females because the mother-daughter relationship is the only bond of sufficient strength to provide the basis for an investment which is asymmetric in the short-term and reciprocal only over the length of a life-time. Any benefits that accrue from kin selection are considered to be secondary.
Most primates live in social groups in which affiliative bonds exist between individuals. Because these bonds need to be maintained through social interactions (grooming in most primates), sociality will be limited by time constraints. It has previously been shown that the time primates invest in grooming increases with group size. However, when groups become too large, individuals will not have enough time available to service all possible social relationships and group cohesion is expected to decrease. In this study, we used data from previously published studies to determine how large groups compromise on their grooming time and how ecological, phylogenetic and life history variables affect time invested in grooming (across species as well as within taxa). We used path analysis to analyse direct and indirect (via group size) effects on grooming. We showed that not only is grooming time determined by group size, but it is also affected by dispersal patterns and sex ratio. Furthermore, we found that grooming time is asymptotic when group size exceeds 40 individuals, indicating that time constraints resulting from ecological pressure force individuals to compromise on their grooming time. This was true across species, but a similar effect was also found within taxa. Cognitive constraints and predation pressure strongly affect group sizes and thereby have an indirect effect on primate grooming time. Primates that were found to live in groups larger than predicted by their neocortex size usually suffered from greater predation risk. However, most populations in our analysis were placed well within what we define as their eco-cognitive niche.
Two general kinds of theory (one ecological and one social) have been advanced to explain the fact that primates have larger brains and greater congnitive abilities than other animals. Data on neocortex volume, group size and a number of behavioural ecology variables are used to test between the various theories. Group size is found to be a function of relative neocortical volume, but the ecological variables are not. This is interpreted as evidence in favour of the social intellect theory and against the ecological theories. It is suggested that the number of neocortical neurons limits the organism's information-processing capacity and that this then limits the number of relationships that an individual can monitor simultaneously. When a group's size exceeds this limit, it becomes unstable and begins to fragment. This then places an upper limit on the size of groups which any given species can maintain as cohesive social units through time. The data suggest that the information overload occurs in terms of the structure of relationships within tightly bonded grooming cliques rather than in terms of the total number of dyads within the group as a whole that an individual has to monitor. It thus appears that, among primates, large groups are created by welding together sets of smaller grooming cliques. One implication of these results is that, since the actual group size will be determined by the ecological characteristics of the habitat in any given case, species will only be able to invade habitats that require larger groups than their current limit if they evolve larger neocortices.
Grooming is a widespread activity throughout the animal kingdom, but in primates (including humans) social grooming, or allo-grooming (the grooming of others), plays a particularly important role in social bonding which, in turn, has a major impact on an individual's lifetime reproductive fitness. New evidence from comparative brain analyses suggests that primates have social relationships of a qualitatively different kind to those found in other animal species, and I suggest that, in primates, social grooming has acquired a new function of supporting these. I review the evidence for a neuropeptide basis for social bonding, and draw attention to the fact that the neuroendrocrine pathways involved are quite unresolved. Despite recent claims for the central importance of oxytocin, there is equally good, but invariably ignored, evidence for a role for endorphins. I suggest that these two neuropeptide families may play different roles in the processes of social bonding in primates and non-primates, and that more experimental work will be needed to tease them apart.
Social relationships are integral to the behaviour of many mammalian species. Primates are unusual in that their social relationships are extensive within groups, which often contain many reproductively active males and females. Several hypotheses have been forwarded to explain the ultimate causation of primate sociality. While attention has focused on grooming as a proximate factor influencing social relationships, the neural basis of such behaviour has not been investigated in monkeys. This report presents changes in the brain's opioid system contingent on grooming in monkeys. Opiates themselves have a feedback interaction with grooming behaviour, as revealed from the administration of opiate agonists and antagonists. Opiate receptor blockade increases the motivation to be groomed, while morphine administration decreases it. These data support the view that brain opioids play an important role in mediating social attachment and may provide the neural basis on which primate sociality has evolved.
The mammalian hypoglossal canal transmits the nerve that supplies the muscles of the tongue. This canal is absolutely and relatively larger in modern humans than it is in the African apes (Pan and Gorilla). We hypothesize that the human tongue is supplied more richly with motor nerves than are those of living apes and propose that canal size in fossil hominids may provide an indication about the motor coordination of the tongue and reflect the evolution of speech and language. Canals of gracile Australopithecus, and possibly Homo habilis, fall within the range of extant Pan and are significantly smaller than those of modern Homo. The canals of Neanderthals and an early “modern” Homo sapiens (Skhul 5), as well as of African and European middle Pleistocene Homo (Kabwe and Swanscombe), fall within the range of extant Homo and are significantly larger than those of Pan troglodytes. These anatomical findings suggest that the vocal capabilities of Neanderthals were the same as those of humans today. Furthermore, the vocal abilities of Australopithecus were not advanced significantly over those of chimpanzees whereas those of Homo may have been essentially modern by at least 400,000 years ago. Thus, human vocal abilities may have appeared much earlier in time than the first archaeological evidence for symbolic behavior.
• language evolution
• human evolution
• Homo
• Pan
• Australopithecus
Many cognitive and physical features must have undergone change for the evolution of fully modern human language. One neglected aspect is the evolution of increased breathing control. Evidence presented herein shows that modern humans and Neanderthals have an expanded thoracic vertebral canal compared with australopithecines and Homo ergaster, who had canals of the same relative size as extant nonhuman primates. Based on previously published analyses, these results demonstrate that there was an increase in thoracic innervation during human evolution. Possible explanations for this increase include postural control for bipedalism, increased difficulty of parturition, respiration for endurance running, an aquatic phase, and choking avoidance. These can all be ruled out, either because of their evolutionary timing, or because they are insufficiently demanding neurologically. The remaining possible functional cause is increased control of breathing for speech. The main muscles involved in the fine control of human speech breathing are the intercostals and a set of abdominal muscles which are all thoracically innervated. Modifications to quiet breathing are essential for modern human speech, enabling the production of long phrases on single expirations punctuated with quick inspirations at meaningful linguistic breaks. Other linguistically important features affected by variation in subglottal air pressure include emphasis of particular sound units, and control of pitch and intonation. Subtle, complex muscle movements, integrated with cognitive factors, are involved. The vocalizations of nonhuman primates involve markedly less respiratory control. Without sophisticated breath control, early hominids would only have been capable of short, unmodulated utterances, like those of extant nonhuman primates. Fine respiratory control, a necessary component for fully modern language, evolved sometime between 1.6 Mya and 100,000 ya.
The evolution of speech can be studied independently of the evolution of language, with the advantage that most aspects of speech acoustics, physiology and neural control are shared with animals, and thus open to empirical investigation. At least two changes were necessary prerequisites for modern human speech abilities: (1) modification of vocal tract morphology, and (2) development of vocal imitative ability. Despite an extensive literature, attempts to pinpoint the timing of these changes using fossil data have proven inconclusive. However, recent comparative data from nonhuman primates have shed light on the ancestral use of formants (a crucial cue in human speech) to identify individuals and gauge body size. Second, comparative analysis of the diverse vertebrates that have evolved vocal imitation (humans, cetaceans, seals and birds) provides several distinct, testable hypotheses about the adaptive function of vocal mimicry. These developments suggest that, for understanding the evolution of speech, comparative analysis of living species provides a viable alternative to fossil data. However, the neural basis for vocal mimicry and for mimesis in general remains unknown.
Human evolution. Harmondsworth: Pelican
- R I M Dunbar
- RIM Dunbar
Dunbar, R. I. M. (2014a). Human evolution. Harmondsworth: Pelican.
Fireside chat: The impact of fire on hominin socioecology
- R I M Dunbar
- J A J Gowlett
The costs of being a high latitude hominin Lucy to language: The benchmark papers
- E Pearce