Differences and Interactions Between Cerebral Hemispheres When Processing Ambiguous Words
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It is well known that the brain (especially the cortex) is structurally separable into two hemispheres. Many neuropsychological studies show that the process of ambiguity resolution requires the intact functioning of both cerebral hemispheres. Moreover, these studies suggest that while the Left Hemisphere (LH) quickly selects one alternative, the Right Hemisphere (RH) maintains alternate meanings. However, these hemispheres are connected through the corpus callosum and presumably the exchange of information is useful. In addition, many works show that the Left Hemisphere (LH) is more influenced by the phonological aspect of written words whereas lexical processing in the Right Hemisphere (RH) is more sensitive to visual form.This distinction suggests that the interconnections between the hemispheres may be used to strengthen or correct incorrect interpretations by one hemisphere. We test this hypothesis by (I) postulating that in the Left Hemisphere (LH) orthography, phonology and semantics are interconnected while (II) the Right Hemisphere (RH), phonology is not connected directly to orthography and hence its influence must be mitigated by semantical processing (III) seeing if corrections in ambiguous word processing can be aided by information in the other hemisphere. We investigate this by complementary human psychophysical experiments and by dual (one RH and one LH) computational neural network model architecturally modified from Kawamoto’s (1993) model to follow our hypothesis. Since the different models have different rates of convergence, we test (III) by halting processing, and using an analogue to priming to compare the rate of convergence to a corrected semantics in the LH working alone and working with information obtained from the RH at the same point in processing. In this paper we present results of the computational model and show that (I) the results obtained from the two hemispheres separately are analogous to the human experiments and (II) the use of the RH information does indeed help such corrections.
KeywordsLeft Hemi Ambiguity Resolution Ambiguous Word Right Hemisphere Phonological Code
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- 1.Beeman, M: Coarse semantic coding and discourse comprehension. In: Beeman, M., Chiarello, C. (eds.) Right hemisphere language comprehension: Perspectives from cognitive neuroscience, pp. 255–284. Lawrence Erlbaum Associates, Mahwah (N.J.) (1998)Google Scholar
- 4.Burgess, C., Lund, K.: Modeling cerebral asymmetries in high- dimensional space. In: Beeman, M., Chiarello, C. (eds.) Right hemisphere language comprehension: Perspectives from cognitive neuroscience, pp. 215–244. Lawrence Erlbaum Associates, Mahwah, NJ (1998)Google Scholar
- 8.Frost, R., Bentin, S.: Processing phonological and semantic ambiguity: Evidence from semantic priming at different SOAs. Journal of Experimental Psychology: Learning, Memory, and Cognition 18, 58–68 (1992)Google Scholar
- 18.Marsolek, C.J., Kosslyn, S.M., Squire, L.R.: Form-specific visual priming in the right cerebral hemisphere. Journal of Experimental Psychology: Learning, Memory, and Cognition 18, 492–508 (1992)Google Scholar
- 23.Swinney, D., Love, T.: Context effects on lexical processing during auditory sentence comprehension; on the time course and neurological bases of a basic comprehension process. In: Witruk, Friederici, Lachmann (eds.) Basic Functions of Language, Reading and Reading Disability, Section 2, ch. 1, pp. 25–40. Kluwer Academic, Dordrecht (2002)CrossRefGoogle Scholar
- 25.Thivierge, J.P., Titone, D., Shultz, T.R.: Simulating frontotemporal pathways involved in lexical ambiguity resolution. Poster Proceedings of the Cognitive Science Society (2005)Google Scholar
- 27.Van Orden, G.C, Kloos, H.: The question of phonology and reading. In: Snowling, M.S., Hulme, C., Seidenberg, M. (eds.) The science of reading: A handbook, Blackwell Pub., Malden (2005)Google Scholar
- 29.Zaidel, E.: Reading in the disconnected right hemisphere: An aphasiological perspective Dyslexia: Neuronal. Cognitive and Linguistic Aspects Oxford 35, 67–91 (1982)Google Scholar