Language as an emergent function: some radical neurological and evolutionary implications (original) (raw)
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A Proposed Neurological Interpretation of Language Evolution
Behavioural Neurology, 2015
Since the very beginning of the aphasia history it has been well established that there are two major aphasic syndromes (Wernicke'stype and Broca's-type aphasia); each one of them is related to the disturbance at a specific linguistic level (lexical/semantic and grammatical) and associated with a particular brain damage localization (temporal and frontal-subcortical). It is proposed that three stages in language evolution could be distinguished: (a) primitive communication systems similar to those observed in other animals, including nonhuman primates; (b) initial communication systems using sound combinations (lexicon) but without relationships among the elements (grammar); and (c) advanced communication systems including word-combinations (grammar). It is proposed that grammar probably originated from the internal representation of actions, resulting in the creation of verbs; this is an ability that depends on the so-called Broca's area and related brain networks. It is suggested that grammar is the basic ability for the development of so-called metacognitive executive functions. It is concluded that while the lexical/semantic language system (vocabulary) probably appeared during human evolution long before the contemporary man (Homo sapiens sapiens), the grammatical language historically represents a recent acquisition and is correlated with the development of complex cognition (metacognitive executive functions).
Foundations of Language: A Biological Paradigm
Many people have argued that the evolution of the human language faculty cannot be explained by Darwinian natural selection. Chomsky and Gould have suggested that language may have evolved as the by-product of selection for other abilities or as a consequence of asyet unknown laws of growth and form. Others have argued that a biological specialization for grammar is incompatible with every tenet of Darwinian theory, that it shows no genetic variation, could not exist in any intermediate forms, confers no selective advantage, and would require more evolutionary time and genomic space than is available. The present paper examines these arguments and illustrate that they depend on inaccurate assumptions about biology or language or both. Human language meets this criterion: grammar is a complex mechanism tailored to the transmission of propositional structures through a serial interface. Reviewing other arguments and data, the paper concludes that there is every reason to believe that a specialization for grammar evolved by a conventional neo-Darwinian process. All languages are complex computational systems employing the same basic kinds of rules and representations, with no notable correlation with technological progress: the grammars of industrial societies are no more complex than the grammars of hunter-gatherers. Within societies, individual humans are proficient language users regardless of intelligence, social status, or level of education. Disease or injury can make people linguistic savants while severely retarded, or linguistically impaired with normal intelligence. Nevertheless, some language disorders are genetically transmitted. Aspects of language skill can be linked to characteristic regions of the human brain. The human vocal tract is tailored to the demands of speech, compromising other functions such as breathing and swallowing. Human auditory perception shows complementary specializations toward the demands of decoding speech sounds into linguistic segments. The present proposal tried to explore the basic problems visà-vis the foundations of human language within a biological paradigm. It seeks an explanation of some basic issues concerning the evolutionary dynamics of human language within a biolinguistic framework. In addition to some theoretical notions, the paper also tries to explain the complexity, its biological design, innateness, lateralization, modularity and genetic adaption of human language system. Finally, it attempts to explain the suggestive biology-language homologies, and location of language in brain centers, and at narrower level in the genetic material.
Evolution, brain, and the nature of language
Trends in cognitive sciences, 2013
Language serves as a cornerstone for human cognition, yet much about its evolution remains puzzling. Recent research on this question parallels Darwin's attempt to explain both the unity of all species and their diversity. What has emerged from this research is that the unified nature of human language arises from a shared, species-specific computational ability. This ability has identifiable correlates in the brain and has remained fixed since the origin of language approximately 100 thousand years ago. Although songbirds share with humans a vocal imitation learning ability, with a similar underlying neural organization, language is uniquely human.
The Biological Nature of Human Language
Biolinguistics, 2010
Biolinguistics aims to shed light on the specifically biological nature of human language, focusing on five foundational questions: (1) What are the properties of the language phenotype? (2) How does language ability grow and mature in individuals? (3) How is language put to use? (4) How is language implemented in the brain? (5) What evolutionary processes led to the emergence of language? These foundational questions are used here to frame a discussion of important issues in the study of language, exploring whether our linguistic capacity is the result of direct selective pressure or due to developmental or biophysical constraints, and assessing whether the neural/computational components entering into language are unique to human language or shared with other cognitive systems, leading to a discussion of advances in theoretical linguistics, psycholinguistics, comparative animal behavior and psychology, genetics/genomics, disciplines that can now place these longstanding questions in a new light, while raising challenges for future research.
Do principles of language processing in the brain affect the way grammar evolves over time or is language change just a matter of socio-historical contingency? While the balance of evidence has been ambiguous and controversial, we identify here a neurophysiological constraint on the processing of language that has a systematic effect on the evolution of how noun phrases are marked by case (i.e. by such contrasts as between the English base form she and the object form her). In neurophysiological experiments across diverse languages we found that during processing, participants initially interpret the first base-form noun phrase they hear (e.g. she. . .) as an agent (which would fit a continuation like . . . greeted him), even when the sentence later requires the interpretation of a patient role (as in . . . was greeted). We show that this processing principle is also operative in Hindi, a language where initial base-form noun phrases most commonly denote patients because many agents receive a special case marker ("ergative") and are often left out in discourse. This finding suggests that the principle is species-wide and independent of the structural affordances of specific languages. As such, the principle favors the development and maintenance of case-marking systems that equate base-form cases with agents rather than with patients. We confirm this evolutionary bias by statistical analyses of phylogenetic signals in over 600 languages worldwide, controlling for confounding effects from language contact. Our findings suggest that at least one core property of grammar systematically adapts in its evolution to the neurophysiological conditions of the brain, independently of socio-historical factors. This opens up new avenues for understanding how specific properties of grammar have developed in tight interaction with the biological evolution of our species.
Biological nature of human language
Biolinguistics aims to shed light on the specifically biological nature of human language, focusing on five foundational questions: (1) What are the properties of the language phenotype? (2) How does language ability grow and mature in individuals? (3) How is language put to use? (4) How is language implemented in the brain? (5) What evolutionary processes led to the emergence of language? These foundational questions are used here to frame a discussion of important issues in the study of language, exploring whether our linguistic capacity is the result of direct selective pressure or due to developmental or biophysical constraints, and assessing whether the neural/computational components entering into language are unique to human language or shared with other cognitive systems, leading to a discussion of advances in theoretical linguistics, psycholinguistics, comparative animal behavior and psychology, genetics/genomics, disciplines that can now place these longstanding questions in a new light, while raising challenges for future research.
The evolutionary dynamics of language
Bio Systems, 2018
The well-established framework of evolutionary dynamics can be applied to the fascinating open problems how human brains are able to acquire and adapt language and how languages change in a population. Schemas for handling grammatical constructions are the replicating unit. They emerge and multiply with variation in the brains of individuals and undergo selection based on their contribution to needed expressive power, communicative success and the reduction of cognitive effort. Adopting this perspective has two major benefits. (i) It makes a bridge to neurobiological models of the brain that have also adopted an evolutionary dynamics point of view, thus opening a new horizon for studying how human brains achieve the remarkably complex competence for language. And (ii) it suggests a new foundation for studying cultural language change as an evolutionary dynamics process. The paper sketches this novel perspective, provides references to empirical data and computational experiments, an...
Thinking outside the cortex: social motivation in the evolution and development of language
Developmental Science, 2011
Alteration of the organization of social and motivational neuroanatomical circuitry must have been an essential step in the evolution of human language. Development of vocal communication across species, particularly birdsong, and new research on the neural organization and evolution of social and motivational circuitry, together suggest that human language is the result of an obligatory link of a powerful cortico-striatal learning system, and subcortical socio-motivational circuitry. Introduction The essential modification in human evolution enabling language has been addressed for decades. In adults, language is demonstrably dependent on the cortex, so the essential evolutionary modification for language has reasonably been sought in the quality or quantity of cortical computations found there. The crystallized product of a lifelong learning process may not be the best source of insight, however, about what initial alterations permitted it. Language plasticity after early damage raises the most perplexing questions about what in the cortex allows language. The right half of the cortex may be removed, or the left half, and language still develops. The frontal cortex may be removed or severely reduced. Uncomfortably for capacity arguments, total cortical volume may be reduced wholesale by prenatal genetic accident, such as Down’s syndrome, or by postnatal accident, and yet language will often survive (Bates, Reilly, Wulfeck, Dronkers, Opie, Fenson, Kiz, Jeffries, Miller & Herbst, 2001; Bates, 2004). An individual may be deaf, blind, or blind and deaf together, and with dedicated tutelage will still learn language with what remains. What conceivable sensory specialization or cortical alteration could survive these assaults? We will remain agnostic on the cognitive and cortical architecture of language. Instead, we will highlight the changes in human sociality and its motivational correlates, and explore motivation’s mechanistic links to language. Of course, unique aspects of human social structure have already been explored widely and at multiple levels. A general coupling between growth of the neocortex and increasing social complexity in primates has been observed (Dunbar & Schultz, 2007). Demonstrations of how human cultures have solved the problem of stabilization of non-kin altruism, that is, how to stabilize social structures and eliminate cheating such that the manifest benefits of extended altruism to social groups can be had, have been explored in number (Wilson, Van Vugt & O’Gorman, 2008; Bowles, 2006; Richerson & Boyd, 2005; Warneken & Tomasello, 2008; Pagel, 2009). In development, human children, contrasted with young chimpanzees, attend to social cues, share information, join games and generally cooperate, serving a form of social learning seen only in humans (Moll & Tomasello, 2007; see also Preston & de Waal, 2001). What is new, and what we are now able to do is place human social behavior more accurately in a comparative and neuroanatomical context, as a transformation of our understanding of the neural circuitry of sociality and its evolutionary variation has occurred (Newman, 1999; Goodson, 2005) (see Figure 1). Making explicit this paper’s goals: why evolution and development of social communication in non-human animals should directly inform language development and evolution in humans We will explore the recent advances in the understanding of the social behavior network and its evolutionary variations, highlighting some key findings for those interested in language learning and comparative cognition. We will make some specific proposals about what kind of neuroanatomical circuitry might be changed to link communication with the most fundamental pleasure and reward in human infants. Further, we will hypothesize that such a link constitutes a socio-motivational ‘gate’ necessary and sufficient for the evolution