The relationship between language production and verbal short-term memory: The role of stress grouping

Abstract

This study investigates the influence of stress grouping on verbal short-term memory (STM). English speakers show a preference to combine syllables into trochaic groups, both lexically and in continuous speech. In two serial recall experiments, auditory lists of nonsense syllables were presented with either trochaic (STRONG–weak) or iambic (weak–STRONG) stress patterns, or in monotone. The acoustic correlates that carry stress were also manipulated in order to examine the relationship between input and output processes during recall. In Experiment 1, stressed and unstressed syllables differed in intensity and pitch but were matched for spoken duration. Significantly more syllables were recalled in the trochaic stress pattern condition than in the iambic and monotone conditions, which did not differ. In Experiment 2, spoken duration and pitch were manipulated but intensity was held constant. No effects of stress grouping were observed, suggesting that intensity is a critical acoustic factor for trochaic grouping. Acoustic analyses demonstrated that speech output was not identical to the auditory input, but that participants generated correct stress patterns by manipulating acoustic correlates in the same way in both experiments. These data challenge the idea of a language-independent STM store and support the notion of separable phonological input and output processes.

Keywords:

• Verbal short-term memory
• Stress grouping
• Speech perception
• Speech production
• Acoustic correlates of stress

Jane L. Morgan and Linda R. Wheeldon are equal first authors on the manuscript. The experiments were designed by these authors and run at the University of Birmingham by Stephanie Edwards who also contributed to the design and analysis. Thanks are also due to three research assistants, Elizabeth Cartwright, Grace Jenkins, and Luke Condley who assisted with data collection and speech measurements of Experiment 2.

Notes

¹ The vast majority of the errors contributing were segmental in nature; therefore, the accuracy scores reported largely reflect segmental accuracy. However, this experiment was not designed to examine segmental error patterns, and a detailed analysis of the segmental data is beyond the scope of this article.