Most of us have likely experienced artificial intelligence (AI) voices through personal assistants like Siri or Alexa, with their flat intonation and mechanical delivery giving us the impression that we could easily distinguish between an AI-generated voice and a real person. But scientists now say the average listener can no longer tell the difference between real people and “deepfake” voices.

In a new study published Sept. 24 in the journal PLoS One, researchers showed that when people listen to human voices — alongside AI-generated versions of the same voices — they cannot accurately identify which are real and which are fake.