Wing-Yee Chow

The structure-sensitivity of memory access: evidence from Mandarin Chinese

The present study examined the processing of the Mandarin Chinese long-distance reflexive ziji to evaluate the role that syntactic structure plays in the memory retrieval operations that support sentence comprehension. Using the multiple-response speed-accuracy tradeoff (MR-SAT) paradigm, we measured the speed with which comprehenders retrieve an antecedent for ziji. Our experimental materials contrasted sentences where zijis antecedent was in the local clause with sentences where zijis antecedent was in a distant clause. Time course results from MR-SAT suggest that ziji dependencies with syntactically distant antecedents are slower to process than syntactically local dependencies. To aid in interpreting the SAT data, we present a formal model of the antecedent retrieval process, and derive quantitative predictions about the time course of antecedent retrieval. The modeling results support the Local Search hypothesis: during syntactic retrieval, comprehenders initially limit memory search to the local syntactic domain. We argue that Local Search hypothesis has important implications for theories of locality effects in sentence comprehension. In particular, our results suggest that not all locality effects may be reduced to the effects of temporal decay and retrieval interference.

A “bag-of-arguments” mechanism for initial verb predictions

ABSTRACT Previous studies have shown that comprehenders use rich contextual information to anticipate upcoming input on the fly, but less is known about how comprehenders integrate different sources of information to generate predictions in real time. The current study examines the time course with which the lexical meaning and structural roles of preverbal arguments impact comprehenders’ lexical semantic predictions about an upcoming verb in two event-related potential (ERP) experiments that use the N400 amplitude as a measure of online predictability. Experiment 1 showed that the N400 was sensitive to predictability when the verbs cloze probability was reduced by substituting one of the arguments (e.g. “The superintendent overheard which tenant/realtor the landlord had evicted … ”), but not when the verbs cloze probability was reduced by simply swapping the roles of the arguments (e.g. “The restaurant owner forgot which customer/waitress the waitress/customer had served … ”). Experiment 2 showed that argument substitution elicited an N400 effect even when the substituted argument appeared elsewhere in the sentence, indicating that verb predictions are specifically driven by the arguments in the same clause as the verb, rather than by a simple “bag-of-words” mechanism. We propose that verb predictions initially rely on a “bag-of-arguments” mechanism, which specifically relies on the lexical meaning, but not the structural roles, of the arguments in a clause.

Prediction as memory retrieval: timing and mechanisms

ABSTRACT In our target article [Chow, W., Smith, C., Lau, E., & Phillips, C. (2015), A “bag-of-arguments” mechanism for initial verb predictions, we investigated the predictions that comprehenders initially make about an upcoming verb as they read and provided evidence that they are sensitive to the arguments’ lexical meaning but not their structural roles. Here we synthesise findings from our work with other studies that show that verb predictions are sensitive to the arguments’ roles if more time is available for prediction. We content that prediction involves computations that may require differing amounts of time. Further, we argue that prediction can be usefully framed as a memory retrieval problem, linking prediction to independently well-understood memory mechanisms in language processing. We suggest that the delayed impact of argument roles on verb predictions may reflect a mismatch between the format of linguistic cues and target event memories. We clarify points of agreement and disagreement with the commentaries, and explain why memory access mechanisms can account for the time course of prediction.

Coreference and Antecedent Representation Across Languages.

Previous studies have shown that speakers of languages such as German, Spanish, and French reactivate the syntactic gender of the antecedent of a pronoun to license gender agreement. As syntactic gender is assumed to be stored in the lexicon, this has motivated the claim that pronouns in these languages reactivate the lexical entry of their antecedent noun. In contrast, in languages without syntactic gender such as English, lexical retrieval might be unnecessary. We used eye-tracking while reading to examine whether antecedent retrieval involves rapid semantic and phonological reactivation. We compared German and English. In German, we found early sensitivity to the semantic but not to the phonological features of the pronoun’s antecedent. In English, readers did not immediately show either semantic or phonological effects specific to coreference. We propose that early semantic facilitation arises due to syntactic gender reactivation, and that antecedent retrieval varies cross-linguistically depending on the type of information relevant to the grammar of each language.

The Relationship Between Anaphor Features and Antecedent Retrieval: Comparing Mandarin Ziji and Ta-Ziji

In the present study we report two self-paced reading experiments that investigate antecedent retrieval processes in sentence comprehension by contrasting the real-time processing behavior of two different reflexive anaphors in Mandarin Chinese. Previous work has suggested that comprehenders initially evaluate the fit between the morphologically simple long-distance reflexive “ziji” and the closest available subject position, only subsequently considering more structurally distant antecedents (Gao et al., 2005; Liu, 2009; Li and Zhou, 2010; Dillon et al., 2014; cf. Chen et al., 2012). In this paper, we investigate whether this locality bias effect obtains for other reflexive anaphors in Mandarin Chinese, or if it is associated specifically with the morphologically simple reflexive ziji. We do this by comparing the processing of ziji to the processing of the morphologically complex reflexive ta-ziji (lit. s/he-self). In Experiment 1, we investigate the processing of ziji, and replicate the finding of a strong locality bias effect for ziji in self-paced reading measures. In Experiment 2, we investigate the processing of the morphologically complex reflexive ta-ziji in the same structural configurations as Experiment 1. A comparison of our experiments reveals that ta-ziji shows a significantly weaker locality bias effect than ziji does. We propose that this results from the difference in the number of morphological and semantic features on the anaphor ta-ziji relative to ziji. Specifically, we propose that the additional retrieval cues associated with ta-ziji reduce interference from irrelevant representations in memory, allowing it to more reliably access an antecedent regardless its linear or structural distance. This reduced interference in turn leads to a diminished locality bias effect for the morphologically complex anaphor ta-ziji.

Eye-tracking evidence for active gap-filling regardless of dependency length

Previous work on real-time sentence processing has established that comprehenders build and interpret filler-gap dependencies without waiting for unambiguous evidence about the actual location of the gap (“active gap-filling”) as long as such dependencies are grammatically licensed. However, this generalisation was called into question by recent findings in a self-paced reading experiment by Wagers and Phillips, which may be taken to show that comprehenders do not interpret the filler at the posited gap when the dependency spans a longer distance. In the present study, we aimed to replicate these findings in an eye-tracking experiment with better controlled materials and increased statistical power. Crucially, we found clear evidence for active gap-filling across all levels of dependency length. This diverges from Wagers and Phillips’s findings but is in line with the long-standing generalisation that comprehenders build and interpret filler-gap dependencies predictively as long as they are grammatically licensed. We found that the effect became smaller in the long dependency conditions in the post-critical region, which suggests the weaker effect in the long dependency conditions may have been undetected in Wagers and Phillips’s study due to insufficient statistical power and/or the use of a self-paced reading paradigm.

Wait a second! delayed impact of argument roles on on-line verb prediction

ABSTRACT Comprehenders can use rich contextual information to anticipate upcoming input on the fly, but recent findings suggest that salient information about argument roles may not impact verb prediction. We took advantage of the word order properties of Mandarin Chinese to examine the time course with which argument role information impacts verb prediction. We isolated the contribution of argument role information by manipulating the order of pre-verbal noun phrase arguments while holding lexical information constant, and we examined its effects on accessing the verb in long-term semantic memory by measuring the amplitude of the N400 component. Experiment 1 showed when the verb appeared immediately after its arguments, even strongly constraining argument role information failed to modulate the N400 response to the verb. An N400 effect emerged in Experiment 2 when the verb appeared at a greater delay. Experiment 3 corroborated the contrast between the first two experiments through a within-participants manipulation of the time interval between the arguments and the verb, by varying the position of an adverbial phrase. These results suggest time is a key factor governing how diverse contextual information contributes to predictions. Here argument role information is shown to impact verb prediction, but its effect is not immediate.