Browsing by Author "Weidinger, Lucas"

Speech, as the evolutionary pinnacle of human communication, is not just defined by its content, but only gains meaning with prosody. Prosody plays a vital role in conveying the words spoken as well as the underlying emotions and intentions of the speaker. While certain aspects of prosody and its relation to emotion have been studied, the concept of sincerity within speech remains a complex and active area of research, spanning linguistic, ethical, and philosophical dimensions. This thesis explored the perception of sincerity in speech through the manipulation of prosodic features using neural network-based speech synthesis. The primary research question explored the impact of modifying prosody on the perceived sincerity of synthetic speech. Three prosodic features — speaking rate, f0-mean, and f0-standard deviation — were evaluated to refine the analysis. Commissive utterances, dependent on sincerity, form the basis of the research material. Data from 40 commissive utterances are subjected to eight prosodic modifications, and linear regression confirms the intended effects. A perception experiment involving 115 native Finnish speakers revealed intriguing results. While the categories of prosodic modifications showed no significant impact on perceived sincerity, analyzing individual prosodic feature values uncovered significant correlations. Increased speaking rate and f0-Standard Deviation correlated positively with perceived sincerity, validating secondary hypotheses. However, no significant correlation was found for increased f0-Mean. The null result in category-based analysis suggests some methodological limitations, possibly obscuring direct conclusions. Nevertheless, the nuanced prosodic features challenge participants' discernment, impacting sincerity evaluation. Due to only partially confirming the hypotheses due to practical constraints, future research avenues hold promise for uncovering deeper insights.