Rapid advancements in artificial intelligence (AI) have enabled text-to-speech (TTS) systems to produce voices increasingly indistinguishable from humans, posing significant societal risks, particularly through potential misuse in fraud and deception. To address this concern, this study combined behavioral assessments and neural measures using electroencephalography (EEG) to examine whether short-term perceptual training enhances people's ability to distinguish AI-generated from human speech. Thirty participants (of either sex) listened to sentences produced by human speakers and corresponding AI-generated clones, judging each sentence as either human or AI-generated before and after a brief (∼12-minute) training session, during which voices were explicitly labeled as "human" or "AI". Behaviorally, participants showed consistently poor discrimination before and after training, with only minimal improvement. However, neural analyses revealed substantial training-induced changes. Specifically, temporal response function (TRF) analysis identified significant neural differentiation between speech types at early (∼55 ms, ∼210 ms) and later (∼455 ms) auditory processing stages following training. Additional EEG analyses, including spectral power and decoding, were conducted to further investigate training effects, but these measures revealed limited differentiation. The findings here highlight a dissociation between behavioral and neural sensitivity: while listeners struggle to behaviorally discriminate sophisticated AI-generated voices, their auditory systems rapidly adapt to subtle acoustic differences following short-term exposure. Understanding this neural-behavioral dissociation is crucial for developing effective perceptual training protocols and informing policies to mitigate societal threats posed by increasingly realistic synthetic voices.Significance Statement Artificial intelligence (AI)-generated voices are becoming increasingly indistinguishable from real human speech, raising serious concerns about fraud as scammers can convincingly impersonate trusted individuals. Our study shows that even when listeners cannot behaviorally distinguish AI-generated voices from real human voices, brief perceptual training enables their brains to detect subtle acoustic differences. Our findings thus reveal a dissociation between neural sensitivity and behavioral performance in recognizing AI-generated speech. By identifying this gap, we highlight an important opportunity: developing specialized training programs that guide listeners to recognize and utilize these subtle differences. Such targeted training could significantly enhance people's ability to identify synthetic voices, offering potential protection against the growing risks of scams and misinformation enabled by increasingly realistic AI speech technologies.
Yang et al. (Mon,) studied this question.