Evaluation of speech perturbation features for measuring authenticity in stress expressions

Abstract

Expressions can vary by the authenticity level, i.e. the real amount of emotion present within the person when expressing it. They are often sincere, and thus authentic and natural; the person expresses what he/she feels. But play-acted expressions are also present in our lives in a form of deception, movies, theater, etc. It was shown in the literature that those two type of expressions are often hard to distinguish. While some studies concluded that play-acted expressions are more intense, exaggerated or stereotypical than the natural ones, other authors failed to detect such a behavior. The goal of our analysis is to investigate whether speech perturbation features, i.e. jitter, shimmer, variance and features of disturbances in laryngeal muscle coordination, can be used as a robust measure for the analysis of the stress expression authenticity. Two subsets of the SUSAS database (Speech Under Simulated and Actual Stress) - the Roller-coaster subset and the Talking Styles Domain - are used for this purpose. It was shown that perturbation features in general show statistically significant difference between realistic and acted expressions, only the jitter features generally failed to discriminate these two type of expressions. The rising trend of perturbation feature values is observed from acted-to real-stress expressions.