Robin I. M. Dunbar
The social hypothesis for language origins is based on the claim that primates use social grooming to bond social groups, and the time available for grooming has an upper limit due to the demands of foraging and food processing. The grooming time is a linear function of group size in both primates and birds so it sets an upper limit to the size of community that can be integrated using the conventional primate mechanism. One of the researchers suggested that language represented a phase shift in communication that allowed this particular glass ceiling to be breached, making it possible for hominins to evolve significantly larger groups than those found among primates. Another researcher showed that the vocal repertoire of the chickadee becomes structurally more complex as group size increases. These findings suggest that the vocal repertoire can become more complex in order to provide a supplementary mechanism for social bonding. The correlation between brain size and group size in primates implies that the first stage of vocal complexity must have occurred with the appearance of the genus Homo around 2 million years ago. The putative demands of instruction in tool manufacture would imply that full-blown language would have evolved at this stage, whereas the social hypothesis requires only an extension of natural primate vocal communication with full grammatical language evolving later.
Bart de Boer
This article focuses on the two different levels that are used to define language. One of the levels is the individual level, where detailed individual behavior is studied and the other is the population level, where individual behavior is averaged and abstracted, and more general trends and processes are studied. Both these levels are intertwined and interdependent and such interaction between the levels can lead to a phenomenon called self-organization. Self-organization is the spontaneous emergence of order in a system that must be spontaneous. The interaction between self-organization and biological evolution is fundamental to understanding the evolution of language. Biological evolution determines the dynamics and the boundary conditions of the self-organizing process. Self-organization causes the language to converge on a limited number of states, the properties of which then determine the fitness of the language-using agents. Biological evolution then selects adaptations that help cope with the properties of the states resulting from self-organization. There are two perspectives on self-organization in language. First is the perspective of an individual's linguistic knowledge, in which linguistic items such as words or speech sounds can be considered as the microscopic level and the complete linguistic system can be considered as the macroscopic level. The second perspective is that of language in a population of speakers, where individual language users constitute the microscopic level, and the whole language community constitutes the macroscopic level.
Chris Knight and Camilla Power
This article examines the social conditions for the evolutionary emergence of language. Human psychology evolved in adaptation to a particular way of life, based on hunting and gathering. Evolving humans compensated for vulnerability to dangerous predators by developing unprecedented forms of social cooperation, material culture, and strategies for remembering, transmitting, and exchanging accumulated knowledge. One of the views known as “deep social mind” holds that distinctively human forms of cultural transmission necessarily co-evolved with cooperative mindreading together with increasing egalitarianism. Humans everywhere may share dispositions toward dominance as a part of the inherited psychological package but equally, humans have corresponding tendencies to resist being dominated. At a certain point in human evolution, the benefits of deploying Machiavellian intelligence to impose dominance over others became matched by the costs of overcoming the Machiavellian resistance of others. The increased human group sizes placed a premium on enhanced social intelligence, the ability to negotiate alliances, in turn driving selection pressures for neocortical expansion. Human hypersociality and intersubjectivity emerged initially under such selection pressures, with mothers increasingly willing to trust allocarers with their babies.