The linguistic processes underlying the P600

Abstract

The P600 is an event-related brain potential (ERP) typically associated with the processing of grammatical anomalies or incongruities. A similar response has also been observed in fully acceptable long-distance wh-dependencies. Such findings raise the question of whether these ERP responses reflect common underlying processes, and what might be the specific mechanisms that are shared between successful processing of well-formed sentences and the detection and repair of syntactic anomalies. The current study presents a comparison of the ERP responses elicited by syntactic violations, garden path sentences, and long-distance wh-dependencies, using maximally similar materials in a within-subjects design. Results showed that a P600 component was elicited by syntactic violations and garden path sentences, but was less robustly elicited in the long-distance wh-dependency condition. Differences in the scalp topography, onset and duration of the P600 effects are characterised in terms of the syntactic operations involved in building complex syntactic structures, with particular attention to retrieval processes, which control the latency of the P600, and structure building processes, which control its duration and amplitude.

Keywords:

• ambiguity
• Event-related potentials
• Left anterior negativity (LAN)
• P600
• Sentence processing
• Syntactic dependencies

Acknowledgements

We would like to thank Virginie van Wassenhove, Anthony Boemio, and Anna Salajegheh for their help with EEG recordings, Anna Salajegheh and Beth Rabbin for their assistance in the preparation of materials, and Brian Dillon for his help with data analyses. This work was supported in part by NSF BCS-0196004, NSF DGE-0801465 and Human Frontiers Science Program RGY-0134 to CP, by NIH R01 DC 05660 to DP and by a fellowship to DP from the Wissenschaftskolleg zu Berlin.

Notes

¹There is some controversy in the ERP literature over the selection of appropriate reference electrodes, and some have argued that a linked mastoid reference risks distortion of the scalp topography of observed effects (Luck, 2005; but see Davidson, Jackson, & Larson, 2000 for a different viewpoint). However, a survey of ERP sentence processing studies that have used linked and unlinked reference electrodes suggests that this choice has little impact upon the major language-related ERP components (linked reference: Donaldson & Rugg, 1999; Friederici, Hahn, & Mecklinger, 1996; Hoeks et al., 2004; Mills, Prat, Zangl, Stager, Neville, & Werker, 2004; Neville et al., 1991; Phillips et al., 2005; unlinked reference: Friederici et al., 2001; Hagoort et al., 2003b; Kaan et al., 2000; Kim & Osterhout, 2005). Moreover, the choice of reference should not impact the timing differences that are the focus of the current study, nor should it create spurious topographic differences among conditions, since we used a fully within-subjects design.