An event related potential investigation of complement set reference Joanne Ingram University of Bedfordshire Linda M Moxey University of Glasgow This experiment was completed as part of an ESRC funded PhD in Psychology at the University of Glasgow. This presentation is sponsored by the ESRC Experimental Pragmatics Network in the UK (Ref: RES ). BACKGROUND It has been suggested that complement set references are driven by a shortfall between expected and denoted amounts [1, 2]. a) Robert expected all of his guests to finish their meal. Few of them emptied their plates. b)They did not really enjoy his cooking. c)They asked for a second helping. After reading a) a suitable continuation may be b), a reference to the complement set (compset). Sentence c) which gives details of the reference set or (refset) seems less suitable. When the shortfall is salient readers focus on the group who did not fulfil the predicate of the sentence. Recent evidence [3] suggests this shortfall may lead to a preferences for compset references in situations with no explicit quantities. d)The waitress was annoyed about the number of customers who left a tip. e)They were not very impressed with her service. f)They were very impressed with her service. In language production after d) participants commonly produced a reference to the compset such as e). Suggests they recognise a shortfall between a character’s desire and their emotion. In an eye-tracking experiment reading was slower after a shortfall, and an inconsistent reference to the refset was seen in later processing measures. CURRENT EXPERIMENT A word which is inconsistent with a given global context may illicit an N400 of greater amplitude than that of a consistent word [4]. Hypothesis – When a shortfall between a character’s implicit desire and their emotion is made salient a reference to the refset will lead to an increase in the amplitude of the N400. METHOD PARTICIPANTS – 18 native speakers of English. DESIGN – 2 (emotion word) x 2 (reference) within participants. MATERIALS – 160 sentences, 80 with a shortfall (-ive emotion word), 80 with no shortfall (+ive emotion word). 80 refset references, 80 compset references. Latin square design. PROCEDURE – 70 Ag/AgCl electrodes recorded EEG activity during reading. RESULTS Grand average waveforms for electrodes Fz, Cz and Pz can be seen in Figure 2. N400 – 410ms to 510ms, 2 (emotion word x 2 (set) x 2 (electrode: Cz, Pz) Huynh-Feldt corrected repeated measures ANOVA. Significant main effect of set (F (1, 17) =4.52, p <0.05). Compset reference more negative than refset references. Figure 2. Grand average waveforms for three representative electrodes (Fz, Cz and Pz). Negativity is plotted downwards. ConditionMaterial Positive/ Reference Set Some people have to wait a long time for an organ transplant. The surgeon was pleased about the number of people willing to donate organs. Their consent would affect a patient’s chances of survival. Positive/ Complement Set Some people have to wait a long time for an organ transplant. The surgeon was pleased about the number of people willing to donate organs. Their refusal would affect a patient’s chances of survival. Negative/ Reference Set Some people have to wait a long time for an organ transplant. The surgeon was annoyed about the number of people willing to donate organs. Their consent would affect a patient’s chances of survival. Negative/ Complement Set Some people have to wait a long time for an organ transplant. The surgeon was annoyed about the number of people willing to donate organs. Their refusal would affect a patient’s chances of survival. Table 1. An example of a material in all 4 conditions. Figure 1. Schematic diagram of experimental procedure. DISCUSSION Compset references led to greater amplitude of N400 component regardless of shortfall. Shortfall information has not been integrated by the reader prior to processing the critical word. Supports previous eye-tracking data [3] where integration of compset references was seen in later measures. Possible that reference to the compset is integrated later due to context dependence as seen when measuring ERPs in response to scalar implicatures [5]. Context crucial in this case as shortfall must be inferred before referent can be identified. POST HOC ANALYSIS Prolonged decrease in positivity at frontal sites for refset references beginning around 600ms post stimulus onset and ending around 1000ms post stimulus onset. In referential ambiguity a frontal shift at this time is associated with difficulty in finding the correct referent [6]. Nref – 600ms to 1000ms, 2 (emotion word) x 2 (set) x 2 (electrode: Fz Afz) Huynh-Feldt corrected repeated measures ANOVA. Significant main effect of set (F (1, 17) =6.69, p < 0.05) with refset references being more negative. Suggests that a processor holds a number of referents in mind whilst reading until a selection is necessary. Supported by research which states that specifically resolving anaphors in situations where reading was coherent was detrimental to processing [7]. REFERENCES [1] Moxey, L. M. (2006). Effects of what is expected on the focussing properties of quantifiers: A test of the presupposition-denial account. Journal of Memory and Language, 55, 422–439. [2] Sanford, A. J., Dawydiak, E., & Moxey, L. (2007). A unified account of quantifier perspective effects in discourse. Discourse Processes, 44, [3] Ingram J., & Moxey, L. M. (in press) Complement set focus without explicit quantity. Journal of Cognitive Psychology. [4] Kutas, M., & Hillyard, S. A. (1980). Reading senseless sentences: Brain potentials reflect semantic incongruity. Science, 207, [5] Noveck, I. A., & Posada, A. (2003). Characterizing the time course of an implicature; an evoked potentials study. 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