Title: Inhibitory modulation of speech trajectories: Evidence from a vowel-modified Stroop task
Legend: Markers (x and o) represent the average formant change, in F1-F2 space, associated with each distractor, relative to the congruent-word origin (0,0). Arrows point to the average location, in the same F1-F2 space, of the distractor words pronounced in a neutral context. Marker data represent the average of 0 to 100 ms, the time window of greatest effect.
Citation: Beach, S. D. & Niziolek, C. A. (in press). Inhibitory modulation of speech trajectories: Evidence from a vowel-modified Stroop task. Cognitive Neuropsychology.
Abstract: How does cognitive inhibition influence speaking? The Stroop effect is a classic demonstration of the interference between reading and color naming. We used a novel variant of the Stroop task to measure whether this interference impacts not only the response speed, but also the acoustic properties of speech. Speakers named the color of words in three categories: congruent (e.g., red written in red), color-incongruent (e.g., green written in red), and vowel-incongruent – those with partial phonological overlap with their color (e.g., rid written in red, grain in green, and blow in blue). Our primary aim was to identify any effect of the distractor vowel on the acoustics of the target vowel. Participants were no slower to respond on vowel-incongruent trials, but formant trajectories tended to show a bias away from the distractor vowel, consistent with a phenomenon of acoustic inhibition that increases contrast between confusable alternatives.
Investigator: Caroline A Niziolek, PhD
About the Lab: The Niziolek lab studies how the feedback system functions in persons with aphasia, many of whom have deficits in speech production and error awareness. They are developing laboratory studies of speech skill learning that can be translated to training interventions for speakers such as these who have trouble consistently producing auditory targets. The lab’s proposed training consists of vocal games that map speech to a real-time visual display. These visual speech training games have the potential to be adapted into tools to improve speech production in individuals with speech impairment, including deaf speakers and children with developmental speech and language disorders.