Incremental processing in the pragmatic interpretation of contrastive prosody

Incremental processing in the pragmatic interpretation of contrastive prosody Chigusa Kurumada kurumada@stanford.edu Dpt. of Linguistics Stanford University Meredith Brown mbrown@bcs.rochester.edu Dpt. of Brain and Cognitive Sciences University of Rochester Daniel F. Pontillo dpontillo@bcs.rochester.edu Dpt. of Brain and Cognitive Sciences University of Rochester Sarah Bibyk sbibyk@bcs.rochester.edu Dpt. of Brain and Cognitive Sciences University of Rochester Michael K. Tanenhaus mtan@bcs.rochester.edu Dpt. of Brain and Cognitive Sciences University of Rochester Abstract We present an eye-tracking experiment investigating the time course with which listeners derive pragmatic inferences from contextual information. We used as a test case the construc- tion “It looks like an X” pronounced either with (a) a nuclear pitch accent on the final noun, or (b) a contrastive L+H* pitch accent and a rising boundary tone, a contour that can sup- port a complex contrastive inference (e.g., It LOOKS like a zebra...(but it is not)). The contrastive intonational contour elicited higher proportions of fixations to non-prototypical tar- get pictures (e.g., a zebra-like animal) during the earliest mo- ments of processing the target noun. Further, when the display only contained a single related pair of pictures, effects of the contrastive accent on “looks” emerged prior to the target noun, indicating that efficient referential resolution is supported by rapidly generated inferences based on visual and prosodic con- text. Figure 1: A sample visual display used in Sedivy et al. (1999) for an instruction “Pick up the tall glass” and resource-demanding processes, such as inference (e.g., Fodor, 1983). This modularity hypothesis, however, lacks an explanation for cases in which expectations based on context can effec- tively constrain parsing decisions. In fact, there is now a large body of research demonstrating that listeners rapidly use information from the linguistic and visual context to re- solve ambiguity (e.g., Altmann 1998; Chambers, Tanenhaus & Magnuson, 2004; Snedeker & Trueswell, 2003). In this constraint-based approach, the context of language use is in- tegral to effective and incremental language processing in guiding expectations (e.g., Levy, 2008). Furthermore, Pianta- dosi, Tily and Gibson (2012) propose that inherent ambiguity in the linguistic signal is in fact a design feature of an efficient encoding system, given the assumption that listeners can inte- grate context information to inferentially resolve ambiguity. Consistent with these accounts, a number of studies using online measures have shown that listeners can, and do, in- corporate visual information to process linguistic input incre- mentally. For example, Sedivy et al. (1999) examined listen- ers’ processing of prenominal adjectives during incremental language processing. They asked participants to manipulate objects based on spoken instructions such as “Pick up the tall glass”. In Figure 1, the pitcher on the lower left is the tallest object, but the glass on the upper left is both tall by compari- son to glasses in general, and taller than the other glass in the upper right-hand corner. Sedivy et al. found that the partial instruction “Pick up the tall —” elicited fixations to the tall member of the contrast pair (e.g., the tall glass) rather than Keywords: Prosody, contrastive accent, pragmatic inferences, eye-tracking. Introduction Few, if any, would question the claim that addressees must make use of context to infer the intentions of a speaker (speaker meaning). Herb Clark (1992) gives a lovely ex- ample to illustrate the richness of context-based inferences. Clark describes a situation in which he addressed the utter- ance, “I’m hot”, to his school-age son, Damon. After go- ing through the plausible pre-compiled senses, Clark notes that none captures his intended (and immediately understood) meaning of his utterance, which could only be inferred from the specific context. Herb and Damon were playing poker and Damon was about to make a large bet. Herb was warning Damon that he should think twice about it. Despite countless everyday examples of this sort, there is also a widely held view that pragmatic inference is external to the core mechanism of language comprehension. For ex- ample, this assumption underlies Levinson’s (2000) influen- tial proposal that common inferences might be pre-compiled as automatically generated defaults, by-passing the need for making a slow and resource intensive inferences (e.g., Neely, 1977; Posner & Snyder, 1975; Shiffrin & Schneider, 1977). This idea receives support from the hypothesis that the re- markable speed and ease of real-time language processing is possible, in part, because of its modularity in the pro- cessing system. A syntactic module, for example, performs computations on restricted inputs without appealing to slow