mirrored file at http://SaturnianCosmology.Org/ For complete access to all the files of this collection see http://SaturnianCosmology.org/search.php ========================================================== *ScienceWeek* * COGNITIVE SCIENCE: ON THE ACQUISITION OF LANGUAGE IN CHILDREN The following points are made by S.J. Hespos and E.S. Spelke (Nature 2004 430:453): 1) Because human languages vary in sound and meaning, children must learn which distinctions their language uses. For speech perception, this learning is selective: initially infants are sensitive to most acoustic distinctions used in any language(1-3), and this sensitivity reflects basic properties of the auditory system rather than mechanisms specific to language(4,5). However, infants' sensitivity to non-native sound distinctions declines over the course of the first year. 2) The authors ask whether a similar process governs learning of word meanings. The authors investigated the sensitivity of 5-month-old infants in an English-speaking environment to a conceptual distinction that is marked in Korean but not English; that is, the distinction between "tight" and "loose" fit of one object to another. 3) The research of the authors focuses on the crosscutting conceptual distinctions between actions producing loose- and tight-fitting contact relationships and actions producing containment versus support relationships. As early as Korean and English children begin to talk about such actions, they categorize them differently from one another and similarly to Korean- and English-speaking adults. Moreover, English and Korean adults differ in their performance on non-linguistic categorization tasks involving heterogeneous examples of these actions, in accord with the differing semantics of their languages, whereas the performance of young children on such tasks has been mixed. These findings suggest that learning the semantics of a natural language influences one's conceptualization of the world. 4) In summary: The authors report that like adult Korean speakers but unlike adult English speakers, the infants in the study detected the investigated distinction and divided a continuum of motion-into-contact actions into tight- and loose-fit categories. Infants' sensitivity to this distinction is apparently linked to representations of object mechanics that are shared by non-human animals. Language learning therefore seems to develop by linking linguistic forms to universal pre-existing representations of sound and meaning. References (abridged): 1. Jusczyk, P. W. The Discovery of Spoken Language (MIT, Cambridge Massachusetts, 1997) 2. Kuhl, P. K. Early linguistic experience and phonetic perception: Implications for theories of developmental speech perception. J. Phonetics 21, 125-139 (1993) 3. Eimas, P. D., Siqueland, E. R., Jusczyk, P. & Vigorito, J. Speech perception in infants. Science 171, 303-306 (1971) 4. Hauser, M. D. The Evolution of Communication (MIT, Cambridge Massachusetts, 1996) 5. Wyttenbach, R. A., May, M. L. & Hoy, R. R. Categorical perception of sound frequency by crickets. Science 273, 1542-1544 (1996) Nature http://www.nature.com/nature -------------------------------- Related Material: ON THE ACQUISITION OF LANGUAGE BY CHILDREN The following points are made by J.R. Saffran et al (Proc. Nat. Acad. Sci. 2001 98:12874): 1) Before infants can begin to map words onto objects in the world, they must determine which sound sequences are words. To do so, infants must uncover at least some of the units that belong to their native language from a largely continuous stream of sounds in which words are seldom surrounded by pauses. Despite the difficulty of this reverse-engineering problem, infants successfully segment words from fluent speech from approximately 7 months of age. 2) How do infants learn the units of their native language so rapidly? One fruitful approach to answering this question has been to present infants with miniature artificial languages that embody specific aspects of natural language structure. Once an infant has been familiarized with a sample of this language, a new sample, or a sample from a different language, is presented to the infant. Subtle measures of surprise (e.g., duration of looking toward the new sounds) are then used to assess whether the infant perceives the new sample as more of the same or something different. In this fashion, we can ask what the infant extracted from the artificial language, which can lead to insights regarding the learning mechanisms underlying the earliest stages of language acquisition. 3) Syllables that are part of the same word tend to follow one another predictably, whereas syllables that span word boundaries do not. In a series of experiments, it has been found that infants can detect and use the statistical properties of syllable co-occurrence to segment novel words. More specifically, infants do not detect merely how frequently syllable pairs occur, but rather the probabilities with which one syllable predicts another. Thus, infants may find word boundaries by detecting syllable pairs with low transitional probabilities. What makes this finding astonishing is that infants as young as 8 months begin to perform these computations with as little as 2 minutes of exposure. By soaking up the statistical regularities of seemingly meaningless acoustic events, infants are able to rapidly structure linguistic input into relevant and ultimately meaningful units. Proc. Nat. Acad. Sci. http://www.pnas.org -------------------------------- Related Material: ON THE GESTURAL ORIGINS OF HUMAN LANGUAGE Notes by ScienceWeek: A view currently held by many anthropologists and linguistics researchers is that the remarkable flexibility of human language is achieved at least in part through the human invention of grammar, a recursive set of rules that allows the generation of sentences of any desired complexity. The linguist Noam Chomsky has attributed this to a unique human endowment termed "universal grammar", with Chomsky suggesting that all human languages are variants of this fundamental endowment. The following points are made by Michael C. Corballis (American Scientist Mar-Apr 1999 87:138): 1) There is little doubt that the great apes (orang-utan, gorilla, chimpanzee) (and perhaps other species such as dolphins) can use symbols to represent actions and objects in the real world, but these animals lack nearly all the other ingredients of true language. 2) Since the common ancestor of human beings and chimpanzees lived approximately 5 million years ago, it is a reasonable inference that grammatical language must have evolved in the hominid line (i.e., the line of human primates) at some point following the split from the line that led to the modern chimpanzee. There has been much disagreement as to when this might have happened. 3) One major view holds that it is impossible to conceive of grammar as having been formed incrementally; grammar therefore must have evolved as a single catastrophic event, probably late in hominid evolution. But many researchers hold a contrary view, that language evolved gradually, shaped by natural selection, and that the cognitive prerequisites of language are already present in the great apes and antedated the split of our hominid ancestors from the chimpanzee line, probably by several million years. 4) The author suggests that at least a partial reconciliation of these alternative perspectives may be that language emerged not from vocalization, but from manual gestures, and switched to a vocal mode relatively recently in hominid evolution, perhaps with the emergence of Homo sapiens. This is an old idea, apparently first suggested by Condillac in the 17th century, but argument in its favor has continued to grow. 5) The author points out that there are countless different sign languages invented by deaf people all over the world, and there is little doubt that these are genuine languages with fully developed grammars. The spontaneous emergence of sign languages among deaf communities everywhere confirms that gestural communication is as natural to the human condition as is spoken language. Indeed, children exposed from an early age only to sign language go through the same basic stages of acquisition as children learning to speak, including a stage when they "babble" silently in sign. 6) The authors proposes the following speculative scenario concerning the historical development of human language: a) 6 or 7 million years ago: Simple gestures first anticipated more complex forms of communication, shortly after the human line diverged from the great apes. At this stage vocalizations served only as emotional cries and alarm calls. b) Approximately 5 million years ago: With the advent of bipedalism, a more sophisticated form of gesturing involving hand signals may have evolved among the early hominids now labelled as "Australopithecus". c) Approximately 2 million years ago: In association with the increasing brain size of the genus Homo, hand gestures became fully syntactic (i.e., with syntax; with ordered arrangements), but vocalizations also became prominent. d) 100,000 years ago: Homo sapiens switched to speech as its primary means of communication, with gestures now playing a secondary role. e) Modern times: The development of telecommunication now permits the routine use of spoken language in the complete absence of hand gestures, but even so, many people find themselves gesturing when they speak on the telephone. 7) Concerning the question of what it was that enabled our species to prevail over other large-brained hominids, the author concludes: "Perhaps the most plausible answer is that they prevailed because of superior technology. But that technology might have resulted, not from an increase in brain size or intelligence, but from a switch from manual to vocal language that allowed them to use their hands for the manufacture of tools and weapons and their voices for instruction." American Scientist http://www.americanscientist.org ScienceWeek http://scienceweek.com * Copyright © 2004 ScienceWeek All Rights Reserved US Library of Congress ISSN 1529-1472