Language production and working memory: The case of subject-verb agreement

Abstract

In order to study the role of working memory in sentence formulation, we elicited errors of subject-verb agreement in spoken sentence completion, while speakers did or did not maintain an extrinsic memory load (a word list). We compared participants with low and high speaking spans (a measure of verbal working memory for sentence production). As in previous studies, agreement errors occurred more frequently for sentence fragments with a singular subject noun and a plural noun than for corresponding fragments in which both nouns were singular. Agreement errors also occurred more frequently when the fragment had a distributive interpretation, so that the conceptual number of the subject mismatched its grammatical number, than when the fragment was not distributive. Importantly, there were effects of memory span and of memory load, and these variables interacted: Load affected only low-span speakers. Distributivity did not interact with either load or span. These data establish that a pivotal syntactic planning process is affected by verbal working memory limitations. As such, they constrain existing proposals about the role of working memory in language production.

Acknowledgement

Rob Hartsuiker was supported by grant E08679 from the Edinburgh University Development Trust Fund. We thank Wendy Huinck, Walter van Heuven, Hubert Voogd, and Marije Van Zee for their kind assistance and Martin Corley, Herman Kolk, Martin Pickering, Baptist Liefooghe, Gabriella Vigliocco, and two anonymous reviewers for helpful comments on earlier versions of this manuscript.

Notes

¹We use the term “resource” here to mean “working memory resource”.

²Span score could not be meaningfully computed for one participant, who scored only 2/5 for one series length, but scored 3/5 for the next length. Neither score could be computed for another participant, who accidentally skipped a series.

³This analysis is equivalent to a regression analysis on the mean of the single and token conditions, with load as a dummy variable and span as a predictor variable (see Miyake, Emerson, and Friedman, 1999 for arguments in support of such an analysis).

⁴A further categorisation of the miscellaneous responses revealed that this effect of local noun number was mostly due to responses in which the number of the local noun was incorrectly repeated or could not be reliably transcribed. This happened more often in the conditions with plural local nouns (123 times) than in the condition with singular local nouns (3 times).

⁵This may be due to a small difference in length: The single token items were 7.7 syllables long and the multiple token items 7.1 syllables.

⁶It is tempting to conclude that agreement becomes less accurate with ageing. In contrast, Hartsuiker et al. (2003b) observed that elderly speakers of German (Experiment 1) produced fewer agreement errors than younger speakers (Experiment 2).

Additional information

Notes on contributors

Robert J. Hartsuiker

Correspondence should be addressed to Robert J. Hartsuiker, Department of Experimental Psychology, Ghent University, Henri Dunantlaan 2, 9000 Ghent, Belgium. [email protected]

Pashiera N. Barkhuysen

The research was conducted in partial fulfilment of Pashiera Barkhuysen's undergraduate degree at Nijmegen University. She is now at the University of Tilburg