Fundamental frequency, frequency jitter, and amplitude shimmer voice algorithms were employed to measure the effects of stress in crewmember communications data in simulated AWACS mission scenarios. Two independent workload measures were used to identify levels of stress: 1) a predictor model developed by the simulation author based upon scenario-generated stimulus events, and 2) the duration of communication for each weapons director, representative of the individual's response to the induced stress. Results identified fundamental frequency and frequency jitter as statistically significant vocal indicators of stress, while amplitude shimmer showed no signs of any significant relationship with workload or stress. Consistent with previous research, the frequency algorithm was identified as the most reliable measure. However, the results did not reveal a sensitive discrimination measure between levels of stress, but rather, did distinguish between the presence or absence of stress.
['William Archer Jones']
An evaluation of voice stress analysis techniques in a simulated AWACS environment