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THE EVOLUTION OF LANGUAGE Introduction • Humans are the only species that has evolved an advanced system of communication between individuals. • Whereas other species communicate through ritualized and repetitious songs, calls, or gestures, humans have developed linguistic systems that can express a literally infinite variety of separate and distinct thoughts. • This incredible evolutionary leap is what distinguished humans from all other organisms on earth. The Evolution of Language • Language first appeared between 30,000 and 100,000 years ago in the species Homo sapiens. • But how did language evolve? • Currently, there are two rival answers to this question: the first and more common explanation is that language was an adaptation of some sort; the second (chiefly espoused by Stephen Jay Gould) is that language is a spandrel, a non-adaptive element arising as a byproduct of other processes. • We will consider these explanations in reverse order. Language as a Spandrel • Some people, Stephen Jay Gould most prominent among them, believe language to be the byproduct of other evolutionary processes, not a special adaptation that arose by ordinary natural selection acting on mutations. • As Gould puts it, "Natural selection made the human brain big, but most of our mental properties and potentials may be spandrels - that is, non-adaptive side consequences of building a device with such structural complexity" (The Pleasures of Pluralism , p.11). • In other words, our ancestors encountered environments which required the type of advanced reasoning only provided by a larger brain; however, language capability was not one of those functions for which the brain was selected. • Instead, language is a result of exapting neural structures formerly used for other functions: "Many, if not most, universal behaviors [including language] are probably spandrels, often co-opted later in human history for important secondary functions" (Ibid). • This view has been reinforced by the famous linguist Noam Chomsky, who argues that the brain's language capability cannot be explained in terms of natural selection. • He attempts to explain the brain not through biology or engineering principles, but instead through the effects of physical laws. • According to Chomsky, there may be unexpected emergent physical properties associated with the specific structure of the brain that explain language. Language as an Adaptation • The mainstream view is that language is an adaptation, evolved in response to some selection pressure toward improved communication between humans. • This explanation is associated with many speculative possibilities and proposals for the adaptive function of language, and some (such as Steven Pinker) postulate "mental modules" that compartmentalize linguistic functions. • There are many different possible "adaptationist" explanations for the evolution of language. • For instance, perhaps there was a need for improved communication between hunters at some point in the history of Homo sapiens, and oral expressions were simply the optimal way to solve the problem. • More plausibly (or at least more importantly), sharing information between individuals probably conferred an extremely major advantage: groups of humans with language, or even "protolanguage", could share a wealth of information about local hunting conditions, food supplies, poisonous plants, or the weather. • It would be extremely beneficial to the survival of all members of the tribe if only one had to encounter a poisonous plant, rather than each member having to rediscover the fact for himself! • It is also simple to imagine a series of "oral gestures", perhaps indicating the presence of an animal to another person by imitating the animal's cries. • Steven Pinker suggests in his book The Language Instinct, "Perhaps a set of quasi-referential calls . . . came under the voluntary control of the cerebral cortex [which controls language], and came to be produced in combination for complicated events; the ability to analyze combinations of calls was then applied to the parts of each call" (p. 352). • Another possible source of selection pressure towards better linguistic abilities is the social group. • Social interactions between people with widely divergent or conflicting interests "make formidable and ever-escalating demands on cognition" (Ibid, p.368). • Increasing cognitive ability could easily have focused on the improvement of language as well, since so many social interactions depend on effective persuasion.