Dale J. Barr
University of Illinois, Urbana-Champaign
Recent psycholinguistic research has investigated how listeners use mutual perspective to resolve ambiguity in referential communication (e.g., Keysar, Barr, Balin, & Brauner, 2000). Although listeners eventually constrain comprehension to shared referents, potential referents that are not shared ("privileged") strongly interfere with comprehension. Currently, there is substantial debate regarding the time-course of mutual perspective. The Perspective Adjustment model of Keysar and Barr assumes that it is used for late-stage error monitoring and correction, whereas cue-based models assume that it exerts a partial constraint from the earliest moments of processing (Hanna, Trueswell, Tanenhaus, & Novick, 1997; Nadig & Sedivy, 2000). It has been difficult to evaluate these competing claims because of (1) vagueness about what counts as the "initial moments" of comprehension; and (2) studies that use a critical baseline condition containing competing shared referents create a global ambiguity that listeners cannot resolve without the speaker's help.
Building on a paradigm established by Allopenna, Magnuson, & Tanenhaus (1998), I conducted an eyetracking experiment that examined the resolution of temporary ambiguity during lexical access. This temporary ambiguity was due to the presence of a lexical competitor (e.g., "parakeet") that shared initial phonemes with a target word (e.g., "parachute"). The experiment was designed to assess three components of lexical access: (1) the pre-activation of targets and competitors before the target word (baseline activation); (2) the boost in activation due to the onset of the target word (lexical activation); (3) the ultimate selection of the target (lexical selection). In the experiment, listeners followed instructions from a confederate to "Click on the _______" from among a set of four pictures on a computer screen. I independently manipulated the presence / absence of a competitor and whether the corresponding picture was visible to the speaker or visible to both the speaker and listener.
Listeners were observed to strategically inhibit hidden pictures prior to the onset of critical word, as reflected in a decreased baseline activation. In spite of these efforts, when this hidden picture was a competitor the likelihood of fixation increased multifold during lexical activation. Lexical selection of the target was delayed when the hidden picture depicted a competitor relative to when it depicted a control object. The pattern of results suggest that mutual perspective has its strongest effects on baseline activation and lexical selection; however, its effects on initial activation may be limited. Implications for models of mutual perspective and theories of lexical access will be discussed.
References
Allopenna, P. D., Magnuson, J. S., & Tanenhaus, M. K. (1998). Tracking the time course of spoken word recognition using eye movements: Evidence for continuous mapping models. Journal of Memory and Language, 38(4), 419-439.
Hanna, J. E., Trueswell, J. C., Tanenhaus, M. K., & Novick, J. M. (1997). Consulting common ground during referential interpretation. Paper presented at the 38th Annual Meeting of the Psychonomic Society, Philadelphia, PA.
Keysar, B., Barr, D. J., Balin, J. A., & Brauner, J. S. (2000). Taking perspective in conversation: The role of mutual knowledge in comprehension. Psychological Science, 11(1), 32-38.
Nadig, A., & Sedivy, J. C. (2000). Children's use of referential pragmatic constraints in production and processing. Paper presented at the 13th CUNY Conference on Human Sentence Processing, La Jolla, CA.