La charla abordará el tema de la evolución del desarrollo del cerebro y la relación entre cambios en su desarrollo y la evolución de las habilidades que sustentan el lenguaje simbólico. El Dr Deacon discutirá como el lenguaje simbólico a constituido un elemento clave para la evolución del cerebro. Su propuesta desafía la concepción de que el lenguaje se sustenta en habilidades innatas específicas y nos obliga a buscar nuevas explicaciones para el origen de las más prominentes características del lenguaje humano.

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Niche construction, evodevo and the human brain. Why human brain evolution was so different.

Terrence W. Deacon, University of California, Berkeley

Neuroantropólogo estadounidense y actualmente
profesor de antropología y miembro de la Facultad
de Ciencias Cognitivas de la Universidad de
California, Berkeley.

Abstract: Although they are proportionately larger than predicted for a primate of our body size, human brains include no uniquely new anatomical structures. And yet human mental abilities are radically unlike those of any other mammal species we know of, particularly when it comes to symbolic capacities and the ways that these have modified memory, emotional experience, and social behavior. By exploring the ways that neurodevelopmental processes can be modulated by brain growth processes during early development it can be shown that both the relative proportions of some brain structures and the patterns of connections between them have been made to deviate from some highly conserved patterns characteristic of other primates. Curiously, these modifications correspond to what are required to support symbolic language abilities. This does not mean that language preceded these changes, but it does suggests that the use of some form of symbolic communication has been a major source of selection pressure affecting human brain evolution for as much as two million years. This can be understood as an unusual variant of niche construction. It is because a symbolic niche is so radically unlike any ecological niche that the effects on brain evolution were so atypical. More interesting still, many of these effects are characteristic of those seen in domestication and out to the relaxation of selection on many otherwise highly conservative features. These include a significant degeneration of regulatory genome control as well as a more flexible distribution of functions within the brain. Paradoxically, it appears that the degeneration of otherwise genetically constrained brain functions may actually have facilitated our capacity to acquire and use language. This challenges the still dominant belief that human language is supported by innate language-specific knowledge. It also forces us to look elsewhere to explain many of the most nearly universal features of language.