Effect of experimentally induced stress on vocal parameters

In a factorially designed experiment, the factors of mode of stress (cognitive vs emotional) and degree of stress (low vs high) were studied in their effect on phonatory and articulatory processes during speech production. 33 male and 27 female university students were selected to represent 3 types of personality (low-anxiety, high-anxiety, anxiety-denying) on the basis of German versions of the Taylor Manifest Anxiety Scale and a social desirability scale. Using digital speech analysis procedures, mean fundamental frequency (FF), FF floor, formant location, and spectral energy distribution were extracted from the experimental speech samples. Although mean FF did not covary with stress manipulation, FF floor of high-anxious and anxiety-denying Ss increased with stress, probably due to physiologically based changes in muscle tension. For articulatory processes, as measured through formant location and spectral composition, significant changes were found for females. For anxiety-denying female Ss, precision of articulation increased under cognitive stress and decreased under emotional stress