Precision of phonological errors in aphasia supports resource models of phonological working memory in language production

ABSTRACT

Working memory (WM) is critical for many cognitive functions including language production. A key feature of WM is its capacity limitation. Two models have been proposed to account for such capacity limitation: slot models and resource models. In recent years, resource models have found support in both visual and auditory perception, but do they also extend to production? We investigate this by analyzing sublexical errors from four individuals with aphasia. Using tools from computational linguistics, we first define the concept of “precision” of sublexical errors. We then demonstrate that such precision decreases with increased working memory load, i.e., word length, as predicted by resource models. Finally, we rule out alternative accounts of this effect, such as articulatory simplification. These data provide the first evidence for the applicability of the resource model to production and further point to the generalizability of this account as a model of resource division in WM.

KEYWORDS:

• Aphasia
• language production
• working memory
• speech errors

Acknowledgments

We thank Christopher Hepner and Jessa Westheimer for their help with data collection, coding, and calculating ALINE scores. We also thank the SCALE in Baltimore, patients and their families. Finally, we thank Adam Buchwald and one anonymous reviewer for their helpful comments on an earlier draft of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 The question of how to quantitatively measure perceptual salience is still contested. Here, we adopt the values from Kondrak (2000), which weight manner and place as the most salient features, while other features (like aspiration) as weighted less heavily.

Additional information

Funding

This work was supported by National Institute of General Medical Sciences [grant number T32GM081760, T32GM142630].