Voice deep fakes sound realistic but not (yet) hyperrealistic

AI-generated voices are increasingly prevalent in our lives, via virtual assistants, automated customer service, and voice-overs. With increased availability and affordability of AI-generated voices, we need to examine how humans perceive them. Recently, an intriguing effect was reported in AI-generated faces, where such face images were perceived as more human than images of real humans - a “hyperrealism effect.” Here, we tested whether a “hyperrealism effect” also exists for AI-generated voices. We investigated the extent to which AI voices sound real to human listeners, and whether listeners can accurately distinguish between human and AI voices. We also examined perceived social trait characteristics (trustworthiness and dominance) of human and AI voices. We tested these questions using AI voices generated with and without a specific human counterpart (i.e., voice clones/deep fakes, and voices generated from the latent space of a large voice model).We find that deep fake voices can sound as real as human voices, making it difficult for listeners to distinguish between them. However, we did not observe a hyperrealism effect. Both types of AI-generated voices were evaluated as more dominant than human voices, with some AI voices also being perceived as more trustworthy.These findings raise questions for future research: Can hyperrealistic voices be created with more advanced technology, or is the lack of a hyperrealism effect due to differences between voice and face (image) perception? Our findings also highlight the potential for AI voices to misinform and fraud, alongside opportunities to use realistic AI-generated voices for beneficial purposes.