Deaf Readers' Lack of Implicit-Prosody Effects

Deaf Readers’ Lack of Implicit-Prosody Effects Mari Kobayashi Edson T. Miyamoto (etm@lingua.tsukuba.ac.jp) Kaori Sato University of Tsukuba College of Japanese Language and Culture Tsukuba, Ibaraki 305-8572 Japan written words or the way that working memory handles longer phrases could be the crucial factor. Ideally, one would like to compare how silent reading is conducted with and without implicit prosody, but this is not easily achieved (but see Miyamoto, Nakamura & Takahashi, 2004, Experiment 2; Slowiaczek & Clifton, 1980, on the possibility of eliminating inner speech dur- ing reading through simultaneous articulation of non- sense syllables). We report the results of a fragment completion study with deaf readers of Japanese, which indicate that they are not sensitive to the manipulations used by Hirose (2003). Therefore, the results support the proposal that the effects are related to prosodic contours rather than working memory or perception, under the assumption that deaf readers are less likely to be affected by implicit prosodic contours during silent reading. Abstract According to the implicit prosody hypothesis, prosodic contours usually associated with spoken utterances are implicitly imposed on sentences read in silence, thereby affecting the interpretation of ambiguous constructions (Fodor 2002). Some of the strongest evidence support- ing this hypothesis manipulated the prosodic length of segments (Hirose 2003). However, such manipulations also increase the number of characters in the critical words, thus the results may not reflect the influence of prosodic factors but rather how perceptual mechanisms and working memory handle written words with larger number of characters. If so, such results should be repli- cable even with readers who have low ability in handling phonological information. We report experimental re- sults suggesting that deaf readers are not sensitive to such length manipulations. This is compatible with the assumption that prosodic contours, and not some other type of length measure, are at stake, therefore providing further support for the implicit prosody hypothesis. Key words: sentence comprehension, deaf, implicit prosody, Japanese, clause boundary, ambiguity Introduction According to the implicit prosody hypothesis (IPH), prosodic contours usually associated with spoken utter- ances are implicitly imposed on sentences read in silence, thereby affecting the interpretation of ambiguous con- structions (Fodor, 2002). The effects of such implicit prosodic contours have been explored recently both in formal syntax as well as in the language processing liter- ature. A number of empirical results have been reported on implicit prosody effects, but many of them have not addressed alternative explanations. The most common type of manipulation increases the length of constituents in order to show that longer phrases are more likely to modify the farther of two potential attachment sites (see Fodor, 2002, for a summary of the relevant studies). One of the strongest sets of results providing support for the IPH has used ambiguous relative clause construc- tions in Japanese (Hirose, 2003; see also Hirose & Kakei, 1998). However, as in other similar studies, the ma- nipulation used leads to unavoidable side-effects such as longer words and phrases measured in number of char- acters, and not just longer in terms of prosodic length as was intended. This is a problem because it allows for the possibility that it is not implicit prosody that is driv- ing the effect. Instead, perceptual processes for longer Ambiguous relative clauses in Japanese Japanese is a head-final language with subject-object- verb order. There are no overt markers to indicate the beginning of embedded clauses, therefore words in the embedded clause are commonly taken to be part of the matrix clause (but see Venditti, in press, for prosodic cues in speech). For example, readers usually inter- pret the fragment in (1) as a single clause (‘Morishita truly trusted the medicine’, where Morishita is a proper name). 1 (1) Morishita-ga shinyaku-o kokorokara shinyooshita PN-nom medicine-acc truly trusted However, when a noun such as yuujintachi-ni ‘friends- dat’ is read after ‘trusted’, it is clear that this verb is part of a relative clause modifying the noun (relative clauses in Japanese precede the noun they modify) and readers have to decide where the beginning of the relative clause is likely to be. The two most common alternatives are the late opening interpretation, in which the relative clause starts after the direct object, and the early open- ing interpretation, in which the relative clause starts at the direct object ‘medicine-acc’ as schematically repre- sented in (2a, b) (Mazuka & Itoh, 1995; see Hirose, 2003, The nominative case marker ( nom ) is usually used for subjects, the accusative marker ( acc ) for direct objects and the dative marker ( dat ) for indirect objects.