Why did Neanderthals go extinct?

Neanderthals (Homo neanderthalensis) were widespread across Europe and Western Asia for a long time, starting about 400,000 years ago. But things began to change when populations of Homo sapiens (earlier members of our own species) migrated from Africa to Europe at about 45,000 years ago. Five thousand years later not a single Neanderthal remained. What happened? To find out, Smithsonian Insider posed a seemingly simple question to Briana Pobiner, paleoanthropologist at the Smithsonian’s National Museum of Natural History.


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Social learning and evolution: the cultural intelligence hypothesis.

If social learning is more efficient than independent individual exploration, animals should learn vital cultural skills exclusively, and routine skills faster, through social learning, provided they actually use social learning preferentially. Animals with opportunities for social learning indeed do so. Moreover, more frequent opportunities for social learning should boost an individual’s repertoire of learned skills. This prediction is confirmed by comparisons among wild great ape populations and by social deprivation and enculturation experiments. These findings shaped the cultural intelligence hypothesis, which complements the traditional benefit hypotheses for the evolution of intelligence by specifying the conditions in which these benefits can be reaped. The evolutionary version of the hypothesis argues that species with frequent opportunities for social learning should more readily respond to selection for a greater number of learned skills. Because improved social learning also improves asocial learning, the hypothesis predicts a positive interspecific correlation between social-learning performance and individual learning ability. Variation among primates supports this prediction. The hypothesis also predicts that more heavily cultural species should be more intelligent. Preliminary tests involving birds and mammals support this prediction too. The cultural intelligence hypothesis can also account for the unusual cognitive abilities of humans, as well as our unique mechanisms of skill transfer.


Posted in Cultural intelligence, Social learning | Tagged ,

Before the Fall of the Roman Republic, Income Inequality and Xenophobia Threatened Its Foundations

Long before Julius Caesar declared himself dictator for life in 44 B.C., essentially spelling the beginning of the end to the Roman Republic, trouble was brewing in the halls of power.

The warning signs were there. Politicians such as Tiberius Gracchus and Gaius Gracchus (together known as the Gracchi brothers) were thwarted from instituting a series of populist reforms in the 100s B.C., then murdered by their fellow senators. Old and unwritten codes of conduct, known as the mos maiorum, gave way as senators struggled for power. A general known as Sulla marched his army on Rome in 87 B.C., starting a civil war to prevent his political opponent from remaining in power. Yet none of these events have become as indelibly seared into Western memory as Caesar’s rise to power or sudden downfall, his murder in 44 B.C.


Posted in Democracy, Inequality | Tagged ,

Cultural Panthropology

Culture, in the most basic sense of “tradition,” has been shown to exist in many species. There is more to the phenomenon of culture in humans, however than the mere existence of traditions. Thus, rather than expecting that culture can be assigned to living or ancestral species in an all-or-none fashion, reconstruction of the evolution of this uniquely complex phenomenon is likely to depend on successfully teasing apart its components, which may have evolved in a somewhat mosaic fashion. In this paper, we dissect ten different aspects of human culture and offer evidence that most of them are manifested in chimpanzees, even if in limited ways, permitting inferences about the cultural profile of our common ancestor. The aspects of culture examined include large-scale patterns of behavioral variation across populations, the mechanisms available for social transmission, and cultural contents. The contrasts thus are drawn from humans and chimpanzees offer a framework for cultural comparisons between other taxa from the past and present.


Posted in Cultural panthropology, Culture, Social learning, Traditions | Tagged , , ,

Stone toolmaking and the evolution of human culture and cognition

Although many species display behavioral traditions, human culture is unique in the complexity of its technological, symbolic and social contents. Is this extraordinary complexity a product of cognitive evolution, cultural evolution or some interaction of the two? Answering this question will require a much better understanding of patterns of increasing cultural diversity, complexity and rates of change in human evolution. Palaeolithic stone tools provide a relatively abundant and continuous record of such change, but a systematic method for describing the complexity and diversity of these early technologies has yet to be developed. Here, an initial attempt at such a system is presented. Results suggest that rates of Palaeolithic culture change may have been underestimated and that there is a direct relationship between increasing technological complexity and diversity. Cognitive evolution and the greater latitude for cultural variation afforded by increasingly complex technologies may play complementary roles in explaining this pattern.


Posted in Cultural accumulation, Cultural complexity, Cultural diversity, Technology | Tagged , , ,

Modelling population contact and interaction of cultural repertoires

Evidence for interactions between populations plays a prominent role in the reconstruction of historical and prehistoric human dynamics; these interactions are usually interpreted to reflect cultural practices or demographic processes. The sharp increase in long-distance transportation of lithic material between the Middle and Upper Palaeolithic, for example, is seen as a manifestation of the cultural revolution that defined the transition between these epochs. Here, we propose that population interaction is not only a reflection of cultural change but also a potential driver of it. We explore the possible effects of inter-population migration on cultural evolution when migrating individuals possess core technological knowledge from their original population. Using a computational framework of cultural evolution that incorporates realistic aspects of human innovation processes, we show that migration can lead to a range of outcomes, including punctuated but transient increases in cultural complexity, an increase of cultural complexity to an elevated steady state and the emergence of a positive feedback loop that drives ongoing acceleration in cultural accumulation. Our findings suggest that population contact may have played a crucial role in the evolution of hominin cultures and propose explanations for observations of Palaeolithic cultural change whose interpretations have been hotly debated.


Posted in Connectivity, Cultural accumulation, Population | Tagged , ,

Partial connectivity increases cultural accumulation within groups

Complex technologies used in most human societies are beyond the inventive capacities of individuals. Instead, they result from a cumulative process in which innovations are gradually added to existing cultural traits across many generations. Recent work suggests that a population’s ability to develop complex technologies is positively affected by its size and connectedness. Here, we present a simple computer-based experiment that compares the accumulation of innovations by fully and partially connected groups of the same size in a complex fitness landscape. We find that the propensity to learn from successful individuals drastically reduces cultural diversity within fully connected groups. In comparison, partially connected groups produce more diverse solutions, and this diversity allows them to develop complex solutions that are never produced in fully connected groups. These results suggest that explanations of ancestral patterns of cultural complexity may need to consider levels of population fragmentation and interaction patterns between partially isolated groups.


Read also: Less connectivity improves innovation

Posted in Cultural accumulation, Cultural innovations, Groups | Tagged , ,

The niche construction of cultural complexity

Interactions between innovations, population size, and the environment.

Niche construction is a process through which organisms alter their environments and, in doing so, influence or change the selective pressures to which they are subject. ‘Cultural niche construction’ refers specifically to the effect of cultural traits on the selective environments of other biological or cultural traits and may be especially important in human evolution. In addition, the relationship between population size and cultural accumulation has been the subject of extensive debate, in part because anthropological studies have demonstrated a significant association between population size and toolkit complexity in only a subset of studied cultures. Here, we review the role of cultural innovation in constructing human evolutionary niches and introduce a new model to describe the accumulation of human cultural traits that incorporates the effects of cultural niche construction. We consider the results of this model in light of available data on human toolkit sizes across populations to help elucidate the important differences between food-gathering societies and food-producing societies, in which niche construction may be a more potent force. These results support the idea that a population’s relationship with its environment, represented here by cultural niche construction, should be considered alongside population size in studies of cultural complexity.


Posted in Cultural complexity, Cultural innovations, Innovation | Tagged , ,

Understanding and sharing intentions: the origins of cultural cognition

We propose that the crucial difference between human cognition and that of other species is the ability to participate with others in collaborative activities with shared goals and intentions: shared intentionality. Participation in such activities requires not only especially powerful forms of intention reading and cultural learning, but also a unique motivation to share psychological states with others and unique forms of cognitive representation for doing so. The result of participating in these activities is species-unique forms of cultural cognition and evolution, enabling everything from the creation and use of linguistic symbols to the construction of social norms and individual beliefs to the establishment of social institutions. In support of this proposal we argue and present evidence that great apes (and some children with autism) understand the basics of intentional action, but they still do not participate in activities involving joint intentions and attention (shared intentionality). Human children’s skills of shared intentionality develop gradually during the first 14 months of life as two ontogenetic pathways intertwine: (1) the general ape line of understanding others as animate, goal-directed, and intentional agents; and (2) a species-unique motivation to share emotions, experience, and activities with other persons. The developmental outcome is children’s ability to construct dialogic cognitive representations, which enable them to participate in earnest in the collectivity that is human cognition.


Posted in Cognition, Cultural cognition, Culture | Tagged , ,

Humans Migrated Out of Africa to Escape Drying Climate

Ancient humans left Africa to escape a drying climate, about 60,000 years ago — a finding that contradicts previous suggestions that humens were able to leave because a then-wet climate allowed them to cross the generally arid Horn of Africa and Middle East. The study is published in the journal Geology.

“It has long been proposed that the out-of-Africa migration was facilitated by wet periods that created green corridors to Eurasia — in other words, the climate pulled people out. We may have to revise this model to one where people were pushed out, due to unfavorable conditions,” said study co-author Dr. Peter deMenocal, of Columbia University.


Posted in Ancient, Climate, Migrations | Tagged , ,