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How abstract is language?
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News & Comment
TRENDS in Cognitive Sciences Vol.5 No.2 February 2001
Journal Club
How abstract is language? Linguists typically argue in favor of abstract representations for language, but many recent approaches to language within the cognitive science framework have stressed the importance of surface forms. In these approaches, abstract representations emerge as secondary properties at best, and at worst, are absent entirely. One domain in which linguists invoke a particularly abstract level of representation is Semitic word formation. In Semitic languages (e.g. Arabic, Hebrew), a word consists of a three-consonant root (e.g. Arabic /ktb/ signifies the semantic domain of writing) which gets interleaved into fixed templates: KaTaB means ‘wrote’, KuTiB means ‘was written’ and maKTaB means ‘desk’. Many of the templates themselves bear consistent meaning of the sort associated with inflectional morphology in English (e.g. Arabic /a-a/ signifies the perfective, /u-i/ the passive). Additional grammatical meanings can be added through prefixes and suffixes. This analysis requires at least three abstract elements in the representation of even a simple word: the root, the template, and the rules (phonological and semantic) for combining
the two. An alternative analysis is simply to say that people who speak these languages know the words katab, kutib, maktab, etc. as independent units and the abstract analysis reflects a level of meta-analysis necessary for linguists but not the average speaker. In a recent paper, Prunet et al. address the question of the psychological validity of abstract roots by examining the speech errors of an Arabic–French bilingual aphasic patient. Using a variety of different production tasks (including reading aloud, repetition and picture naming), they found that their subject made a large number of root errors in Arabic in which he re-ordered root consonants, but almost no errors in the ordering of the template. Thus, if the target word were ‘kutib’, he might say ‘tukib’, but would not say ‘kitub’. Similarly, he showed almost no re-ordering errors involving consonants from the prefixes or suffixes; only consonants from the root were affected. Thus, if the target were ‘maktab’ (ma is a prefix), he might say ‘matkab’ but not ‘kamtab’. When the same patient was tested in French, he showed over 10 times fewer errors of any sort, and the re-orderings most
Vision and touch in parietal area 5 The idea that the construction of an internal representation of the body is based on the synthesis of visual and somatosensory sensations is almost a century old. However, very few studies have examined exactly where and how these two signals are combined in the brain1. In a recent article, Graziano and colleagues report evidence that neurons in monkey parietal area 5 integrate different sensory modalities to create a coherent neural representation of the body2. These researchers assessed the responses of single neurons in area 5 while proprioceptive and visual information about arm position were independently manipulated. They devised an ingenious experiment in which the monkey’s real arm was hidden from view with a shield, and a realistic fake arm was visible above the shield and placed either at the same location or a different location from the monkey’s own arm. Graziano et al. found, as have previous studies, that many area 5
neurons were influenced by proprioceptive inputs from the monkey’s actual arm. More importantly, however, 29% of area 5 neurons were also modulated by the sight of the fake arm, firing at a higher rate when both seen and ‘felt’ (real) arms were at specific spatial locations (e.g. both on the left). To rule out an explanation of the findings in terms of changes in arousal or attentional cueing due to vision of the fake arm, control experiments showed that neurons that responded to the sight of the arm were not affected by the sight of other visual objects (e.g. apple slices) at that location. Moreover, when the fake arm was placed backwards, such that the fingers were near the monkey’s shoulder, area 5 neurons failed to respond to its position in space. Finally, when a left fake arm was ‘attached’ to the right shoulder, visual modulation also vanished. These results allow several conclusions to be drawn. First, they demonstrate that
http://tics.trends.com 1364-6613/01/$ – see front matter © 2001 Elsevier Science Ltd. All rights
often involved switches between adjacent elements as opposed to the discontinuous switches found in Arabic. The authors note that there are other known instances of root consonant re-ordering in Semitic languages: in speech errors of non-aphasic speakers, in childrens language games, and in the historical development of the Semitic languages. Moreover, they review parallel evidence from a different aphasic patient, normal speech errors, and language games showing disruptions to the template that leave the root consonants intact. Taken together, the evidence favors an analysis of Semitic languages that includes the root and template as psychologically real parts of the grammar. This article demonstrates, therefore, the importance of such abstract representations, not only for accounts of language itself, but for understanding how human beings represent and access their language. 1 Prunet, J-F. et al. (2000) The mental representation of Semitic words. Linguist. Inq. 31, 609–648
Laura Wagner [email protected]
neurons in parietal area 5 combine visual and somatosensory signals to represent the location of the arm in space. Second, they show that the crossmodal influence of vision on proprioception depends on the identity of the visual stimulus and not simply on its location. Finally, they suggest that cells in area 5 encode the spatial relationships between parts of the body and, as such, may form the neural basis of the body schema. Interestingly, neurons in somatosensory area S1 were not modulated by visual feedback from the fake arm, suggesting that area 5 might be the first stage at which a multimodal representation of the body appears in the brain. References 1 Ferraina, S. et al. (1997) Visual control of handreaching movement: activity in parietal area 7. Eur. J. Neurosci. 9, 1090–1095 2 Graziano, M.S.A. et al. (2000) Coding the location of arm by sight. Science 290, 1782–1786
Giuseppe di Pellegrino [email protected]
News & Comment
TRENDS in Cognitive Sciences Vol.5 No.2 February 2001
Journal Club
How abstract is language? Linguists typically argue in favor of abstract representations for language, but many recent approaches to language within the cognitive science framework have stressed the importance of surface forms. In these approaches, abstract representations emerge as secondary properties at best, and at worst, are absent entirely. One domain in which linguists invoke a particularly abstract level of representation is Semitic word formation. In Semitic languages (e.g. Arabic, Hebrew), a word consists of a three-consonant root (e.g. Arabic /ktb/ signifies the semantic domain of writing) which gets interleaved into fixed templates: KaTaB means ‘wrote’, KuTiB means ‘was written’ and maKTaB means ‘desk’. Many of the templates themselves bear consistent meaning of the sort associated with inflectional morphology in English (e.g. Arabic /a-a/ signifies the perfective, /u-i/ the passive). Additional grammatical meanings can be added through prefixes and suffixes. This analysis requires at least three abstract elements in the representation of even a simple word: the root, the template, and the rules (phonological and semantic) for combining
the two. An alternative analysis is simply to say that people who speak these languages know the words katab, kutib, maktab, etc. as independent units and the abstract analysis reflects a level of meta-analysis necessary for linguists but not the average speaker. In a recent paper, Prunet et al. address the question of the psychological validity of abstract roots by examining the speech errors of an Arabic–French bilingual aphasic patient. Using a variety of different production tasks (including reading aloud, repetition and picture naming), they found that their subject made a large number of root errors in Arabic in which he re-ordered root consonants, but almost no errors in the ordering of the template. Thus, if the target word were ‘kutib’, he might say ‘tukib’, but would not say ‘kitub’. Similarly, he showed almost no re-ordering errors involving consonants from the prefixes or suffixes; only consonants from the root were affected. Thus, if the target were ‘maktab’ (ma is a prefix), he might say ‘matkab’ but not ‘kamtab’. When the same patient was tested in French, he showed over 10 times fewer errors of any sort, and the re-orderings most
Vision and touch in parietal area 5 The idea that the construction of an internal representation of the body is based on the synthesis of visual and somatosensory sensations is almost a century old. However, very few studies have examined exactly where and how these two signals are combined in the brain1. In a recent article, Graziano and colleagues report evidence that neurons in monkey parietal area 5 integrate different sensory modalities to create a coherent neural representation of the body2. These researchers assessed the responses of single neurons in area 5 while proprioceptive and visual information about arm position were independently manipulated. They devised an ingenious experiment in which the monkey’s real arm was hidden from view with a shield, and a realistic fake arm was visible above the shield and placed either at the same location or a different location from the monkey’s own arm. Graziano et al. found, as have previous studies, that many area 5
neurons were influenced by proprioceptive inputs from the monkey’s actual arm. More importantly, however, 29% of area 5 neurons were also modulated by the sight of the fake arm, firing at a higher rate when both seen and ‘felt’ (real) arms were at specific spatial locations (e.g. both on the left). To rule out an explanation of the findings in terms of changes in arousal or attentional cueing due to vision of the fake arm, control experiments showed that neurons that responded to the sight of the arm were not affected by the sight of other visual objects (e.g. apple slices) at that location. Moreover, when the fake arm was placed backwards, such that the fingers were near the monkey’s shoulder, area 5 neurons failed to respond to its position in space. Finally, when a left fake arm was ‘attached’ to the right shoulder, visual modulation also vanished. These results allow several conclusions to be drawn. First, they demonstrate that
http://tics.trends.com 1364-6613/01/$ – see front matter © 2001 Elsevier Science Ltd. All rights
often involved switches between adjacent elements as opposed to the discontinuous switches found in Arabic. The authors note that there are other known instances of root consonant re-ordering in Semitic languages: in speech errors of non-aphasic speakers, in childrens language games, and in the historical development of the Semitic languages. Moreover, they review parallel evidence from a different aphasic patient, normal speech errors, and language games showing disruptions to the template that leave the root consonants intact. Taken together, the evidence favors an analysis of Semitic languages that includes the root and template as psychologically real parts of the grammar. This article demonstrates, therefore, the importance of such abstract representations, not only for accounts of language itself, but for understanding how human beings represent and access their language. 1 Prunet, J-F. et al. (2000) The mental representation of Semitic words. Linguist. Inq. 31, 609–648
Laura Wagner [email protected]
neurons in parietal area 5 combine visual and somatosensory signals to represent the location of the arm in space. Second, they show that the crossmodal influence of vision on proprioception depends on the identity of the visual stimulus and not simply on its location. Finally, they suggest that cells in area 5 encode the spatial relationships between parts of the body and, as such, may form the neural basis of the body schema. Interestingly, neurons in somatosensory area S1 were not modulated by visual feedback from the fake arm, suggesting that area 5 might be the first stage at which a multimodal representation of the body appears in the brain. References 1 Ferraina, S. et al. (1997) Visual control of handreaching movement: activity in parietal area 7. Eur. J. Neurosci. 9, 1090–1095 2 Graziano, M.S.A. et al. (2000) Coding the location of arm by sight. Science 290, 1782–1786
Giuseppe di Pellegrino [email protected]