Study from Zurich:

What deepfake voices do to our brain

25 test subjects had to decide whether two voices they heard were identical or whether one of them was a deepfake voice.(Bild: Viacheslav Yakobchuk - stock.ado)

The brain reacts differently to artificially imitated voices than to real ones. This happens even if people do not recognize the so-called deepfake voices as fake, as a study by the University of Zurich in the journal "Communications Biology" shows.

Deepfake technologies can imitate a person's unique voice profile very accurately. This is used, for example, for fraud attempts on the telephone, as the university wrote in a press release on Wednesday.

25 test subjects had to recognize deepfake voices
For the study, the researchers recorded the voices of four male speakers and converted them into deepfake voices using computer algorithms. 25 test subjects had to decide whether two voices they heard were identical or whether one of them was a deepfake voice.

In two thirds of cases, the deepfake identities were correctly assigned. "This illustrates that although current deepfake voices do not perfectly mimic identity, they have the potential to deceive people's perceptions," first author Claudia Roswandowitz was quoted as saying in the press release.

However, the brains of the test subjects showed a different picture: The so-called nucleus accumbens, a component of the brain's reward system, was much more active when both voices shown to the test subjects were natural voices. In contrast, the auditory cortex, which is responsible for analyzing sounds, was more active when one of the two voices was a deepfake voice. The first author concluded that humans can therefore only be partially deceived by deepfakes.