Feigned depression and feigned sleepiness: a voice acoustical analysis

We sought to profile the voice acoustical correlates of simulated, or feigned depression by neurologically and psychiatrically healthy control subjects. We also sought to identify the voice acoustical correlates of feigned sleepiness for these same subjects. Twenty-two participants were asked to speak freely about a cartoon, to count from 1 to 10, and to sustain an "a" sound for approximately 5s. These exercises were completed three times (within the same testing session) with three differing sets of instructions to the participants. These three conditions were presented in pseudo-random order to control for any order effects, and all subjects were naïve to the intended purpose of this study. For all three conditions, mean speaking rates and pitch ranges were calculated. A series of paired t tests showed significant differences in the speaking rates (counting numbers and free-speech exercises) between the 'normal' and feigned sleepy conditions, and between the normal and feigned depression conditions, but not between the 'sleepy' and 'depressed' conditions. The results for pitch range, for all speech exercises, were not different between the normal and either the feigned depression or feigned sleepiness conditions. These results indicate that persons feigning depression and sleepiness demonstrate some level of conscious control of their speech rate, but they did not convincingly alter their pitch ranges while feigning depression or sleepiness.