Never seem to find the time: evaluating the physiological time course of visual word recognition with regression analysis of single-item event-related potentials

Abstract

Visual word recognition is a process that, both hierarchically and in parallel, draws on different types of information ranging from perceptual to orthographic to semantic. A central question concerns when and how these different types of information come online and interact after a word form is initially perceived. Numerous studies addressing aspects of this question have been conducted with a variety of techniques [e.g., behaviour, eye-tracking, event-related potentials (ERPs)], and divergent theoretical models, suggesting different overall speeds of word processing, have coalesced around clusters of mostly method-specific results. Here, we examine the time course of influence of variables ranging from relatively perceptual (e.g., bigram frequency) to relatively semantic (e.g., the number of lexical associates) on ERP responses, analysed at the single-item level. Our results, in combination with a critical review of the literature, suggest methodological, analytic and theoretical factors that may have led to inconsistency in results of past studies; we will argue that consideration of these factors may lead to a reconciliation between divergent views of the speed of word recognition.

Keywords:

• visual word recognition
• ERPs
• multiple regression

Acknowledgements

The authors acknowledge B. C. Armstrong, E. Wlotko, D. Groppe and D.C. Plaut for their insightful discussion of the statistical issues involved in analysing the single-item ERP corpus. Numerous research assistants are to be thanked for their part in the collection of the single-item data, especially P. Anaya, H. Buller and C. Laguna.

Funding

This research was supported by NIMH T32 MH019983, NICHD F32HD062043, NIA 5R01AG026308, the James S. McDonnell Foundation 21st Century Science Initiative Scholar Award in Understanding Human Cognition, NSF-CAREER BCS-1252975 and the Research Foundation of the State University of New York.

Notes

1. In this paper, we focus on one prominent model of eye control during reading, which has been central to arguments about timing discrepancies between ERPs and eye movements. There are, of course, other models of eye control such as the SWIFT model (Engbert, Nuthmann, Richter, & Kliegl, 2005), which make different assumptions than E-Z Reader and are not discrepant with the BIAM, even on the surface.

2. In order to collect high-quality data from such a large number of participants in a reasonable period of time, a reduced recording montage was used with only six electrodes at middle prefrontal, left, right, and middle central, middle parietal and middle occiptal sites. As is demonstrated in the meta-reviews of Table 1 and 3, this montage covers the vast majority of topographic regions where effects of lexical variables have been observed in the literature.

3. An exception are the effects reported on the frontal N200 component in Go/Nogo tasks; however, we did not use a Go/Nogo task and thus would not expect N200 effects.

4. Similarly, the time course of the semantic model and the prominence of the lexical association effect are both retained if lexical frequency is simultaneously entered in to the semantic model.

5. Eye-tracking studies showing early effects of expectancy are generally comparing words in highly versus more weakly constraining contexts. Thus, in these studies, it is not possible to determine if effects on gaze are driven by the fit of the target word itself or, as in the ERP data, by the constraint of the prior context.

Additional information

Funding

Funding: This research was supported by NIMH T32 MH019983, NICHD F32HD062043, NIA 5R01AG026308, the James S. McDonnell Foundation 21st Century Science Initiative Scholar Award in Understanding Human Cognition, NSF-CAREER BCS-1252975 and the Research Foundation of the State University of New York.