How Our Ancestors Broke through the Gray Ceiling

Isler, Karin; Schaik, Carel P. van

doi:10.1086/667623

Cited by 129 publications

(51 citation statements)

References 76 publications

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“…The latter would have increasing difficulty supporting themselves, given the increasing reliance on technology or endurance running, and thus probably required energy inputs from others. Finally, their large brain size, well above the so-called grey ceiling for hominoids [45], suggests energy inputs for reproducing females. In other words, H. erectus showed many elements of extensive allomaternal care [9], i.e.…”

Section: From Primate Autarky To Human Catallaxy (A) the Hunter -Gathmentioning

confidence: 99%

How institutions shaped the last major evolutionary transition to large-scale human societies

Powers

Schaik

Lehmann

2016

Phil. Trans. R. Soc. B

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One contribution of 18 to a theme issue 'The evolution of cooperation based on direct fitness benefits'. What drove the transition from small-scale human societies centred on kinship and personal exchange, to large-scale societies comprising cooperation and division of labour among untold numbers of unrelated individuals? We propose that the unique human capacity to negotiate institutional rules that coordinate social actions was a key driver of this transition. By creating institutions, humans have been able to move from the default 'Hobbesian' rules of the 'game of life', determined by physical/environmental constraints, into self-created rules of social organization where cooperation can be individually advantageous even in large groups of unrelated individuals. Examples include rules of food sharing in hunter-gatherers, rules for the usage of irrigation systems in agriculturalists, property rights and systems for sharing reputation between mediaeval traders. Successful institutions create rules of interaction that are self-enforcing, providing direct benefits both to individuals that follow them, and to individuals that sanction rule breakers. Forming institutions requires shared intentionality, language and other cognitive abilities largely absent in other primates. We explain how cooperative breeding likely selected for these abilities early in the Homo lineage. This allowed anatomically modern humans to create institutions that transformed the selfreliance of our primate ancestors into the division of labour of large-scale human social organization.

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Section: From Primate Autarky To Human Catallaxy (A) the Hunter -Gathmentioning

confidence: 99%

How institutions shaped the last major evolutionary transition to large-scale human societies

Powers

Schaik

Lehmann

2016

Phil. Trans. R. Soc. B

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“…Humans in natural fertility populations reproduce more often, and produce larger neonates, than any other living hominoid, yet humans also have the longest lifespans and the largest, most metabolically costly brains 1 (Extended Data Fig. 1).…”

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confidence: 99%

“…Some have hypothesized that a reduced gut 8 or increased locomotor efficiency 9 provided the extra energy needed for brain expansion. However, phylogenetically informed analyses suggest that gut reduction is insufficient to explain increased human brain size 1 , and, although human walking is more economical 10 , traditional hunter–gatherers travel so much farther per day 11 that their daily ranging costs are no lower than wild chimpanzees' (Supplementary Discussion and Supplementary Table 1). Similarly, provisioning of young offspring and their mothers helps to shorten human inter-birth intervals and increase the pace of reproduction 1 , but reproduction remains relatively costly for human mothers (Supplementary Discussion, Supplementary Fig.…”

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confidence: 99%

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Metabolic acceleration and the evolution of human brain size and life history

Pontzer

Brown

Raichlen

et al. 2016

Nature

229

205

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Humans are distinguished from the other living apes in having larger brains and an unusual life history that combines high reproductive output with slow childhood growth and exceptional longevity1. This suite of derived traits suggests major changes in energy expenditure and allocation in the human lineage, but direct measures of human and ape metabolism are needed to compare evolved energy strategies among hominoids. Here we used doubly labelled water measurements of total energy expenditure (TEE; kcal day−1) in humans, chimpanzees, bonobos, gorillas and orangutans to test the hypothesis that the human lineage has experienced an acceleration in metabolic rate, providing energy for larger brains and faster reproduction without sacrificing maintenance and longevity. In multivariate regressions including body size and physical activity, human TEE exceeded that of chimpanzees and bonobos, gorillas and orangutans by approximately 400, 635 and 820 kcal day−1, respectively, readily accommodating the cost of humans' greater brain size and reproductive output. Much of the increase in TEE is attributable to humans' greater basal metabolic rate (kcal day−1), indicating increased organ metabolic activity. Humans also had the greatest body fat percentage. An increased metabolic rate, along with changes in energy allocation, was crucial in the evolution of human brain size and life history.

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“…Furthermore, large brains require large amounts of energy, in particular during ontogeny (Kuzawa et al, 2014). It is thus parsimonious to assume that our ancestors had already started to engage in systematic allomaternal care rather early since otherwise the evolution of our big brains would not have been possible (Isler and van Schaik, 2012).…”

Section: Hunter-gatherers: the Evolutionary Context Of The Emergence mentioning

confidence: 99%

Evolutionary Origins of Morality: Insights From Non-human Primates

2018

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The aim of this contribution is to explore the origins of moral behavior and its underlying moral preferences and intuitions from an evolutionary perspective. Such a perspective encompasses both the ultimate, adaptive function of morality in our own species, as well as the phylogenetic distribution of morality and its key elements across primates. First, with regard to the ultimate function, we argue that human moral preferences are best construed as adaptations to the affordances of the fundamentally interdependent hunter-gatherer lifestyle of our hominin ancestors. Second, with regard to the phylogenetic origin, we show that even though full-blown human morality is unique to humans, several of its key elements are not. Furthermore, a review of evidence from non-human primates regarding prosocial concern, conformity, and the potential presence of universal, biologically anchored and arbitrary cultural norms shows that these elements of morality are not distributed evenly across primate species. This suggests that they have evolved along separate evolutionary trajectories. In particular, the element of prosocial concern most likely evolved in the context of shared infant care, which can be found in humans and some New World monkeys. Strikingly, many if not all of the elements of morality found in non-human primates are only evident in individualistic or dyadic contexts, but not as third-party reactions by truly uninvolved bystanders. We discuss several potential explanations for the unique presence of a systematic third-party perspective in humans, but focus particularly on mentalizing ability and language. Whereas both play an important role in present day, full-blown human morality, it appears unlikely that they played a causal role for the original emergence of morality. Rather, we suggest that the most plausible scenario to date is that human morality emerged because our hominin ancestors, equipped on the one hand with large and powerful brains inherited from their ape-like ancestor, and on the other hand with strong prosocial concern as a result of cooperative breeding, could evolve into an ever more interdependent social niche.

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How Our Ancestors Broke through the Gray Ceiling

Cited by 129 publications

References 76 publications

How institutions shaped the last major evolutionary transition to large-scale human societies

How institutions shaped the last major evolutionary transition to large-scale human societies

Metabolic acceleration and the evolution of human brain size and life history

Evolutionary Origins of Morality: Insights From Non-human Primates

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