The contributions of lexico-semantic and discourse information to the resolution of ambiguous categorical anaphors

Abstract

The present studies employed event-related potentials (ERPs) to examine the time course for the integration of lexico-semantic and discourse information during the resolution of categorical anaphors. Scenarios were constructed to include three potential antecedents. Anaphors were semantically ambiguous in that two of the potential antecedents were exemplars of the anaphor. Final sentences resolved the anaphor with the correct (associatively related/contextually appropriate), incorrect (associatively related/contextually inappropriate), or control antecedent (associatively unrelated/contextually inappropriate). We examined the amplitude of the N400 component, which is thought to reflect the ease of semantic integration, at several points following the anaphor. The smallest N400 was evoked when the text referred back to a correct antecedent following an anaphor; an intermediate N400 was evoked by incorrect antecedents and the largest N400 was evoked by reinstating the control antecedent following an anaphor. Results demonstrated that, following an ambiguous anaphor, readers are able to use both lexico-semantic and discourse-level information to semantically integrate an antecedent into its larger discourse context.

Acknowledgements

This research was supported by NICHD grants HD25889 and HD043251 to Phillip J. Holcomb and by NIMH RO1 MH 071635 to Gina R. Kuperberg. In addition, Dr Kuperberg was supported by National Alliance for Research on Schizophrenia and Depression (through the Sidney Baer Trust), a Claflin Distinguished Scholars Award from Massachusetts General Hospital, and the Institute for Mental Illness and Neuroscience Discovery (MIND).

Notes

¹This experiment was piloted using 400 ms for both sentences 4 and 5 and found that many trials were lost to blinking. On a post-experimental questionnaire, participants never reported noticing a difference between the presentation rate of sentences 4 and 5

²These analyses were also performed on all trials and yielded similar results.

³Although the three-way interaction was significant in one column: medial: F(4, 60) < 1, p = .65; lateral: F(6, 90) < 1, p = .65; peripheral: F(8, 120) = 2.89, p < .05, further exploration did not reveal any differences between the three Reinstatement conditions. To further explore the interaction at peripheral sites, separate Reinstatement × Electrode site ANOVAs were conducted for each Hemisphere. There was no Reinstatement × Electrode site interaction on the left hemisphere: F(8, 120) < 1, p = .61, nor on the right hemisphere: F(8, 120) < 1, p = .53. In addition, these simple effects tests did not show any main effect of Reinstatement at either of these hemispheres, F _max = 1.28, p _min = .29. Examining each electrode site separately, there were no Reinstatement × Hemisphere interactions, F _max = 2.93, p _min = .08.

⁴Although early differences (0–300 ms) were observed to the sentence-final word at peripheral sites, these differences cannot account for the lack of effects seen in the N400 window.

⁵Although small differences were observed shortly after word onset (i.e., 0–300 ms following word onset), neither the magnitude nor pattern of these effects can explain differences in the N400 between the three conditions. These differences will not be discussed further.

⁶Although small differences were observed shortly after word onset (i.e., 0–300 ms following word onset), neither the magnitude nor pattern of these effects can explain differences in the N400 between the three conditions. These differences will not be discussed further.

⁷Responses to a correct probe are consistent with a speed-accuracy trade-off in that participants were slightly (but significantly) less accurate at responding to a correct probe compared with a control probe but also significantly faster in their responses. In the same respect, although participants were significantly more accurate at responding to a control probe, they were slower in their responses as compared with the correct condition. Responses to incorrect probes were both significantly less accurate (as compared with a control) and significantly slower than responses to correct probes (they were no different in speed from control probes). Thus, we are focusing on these responses because they do not seem to be affected by any speed-accuracy trade-off.