AI-powered deepfake videos with altered facial expressions can display realistic heartbeats through skin colour changes, which may hinder one deepfake detection method
By Jeremy Hsu
30 April 2025
Some deepfake videos present a convincing pulse
Alamy Stock Photo
Deepfake videos that feature digital manipulations of people’s facial expressions and voices can also depict realistic heartbeats, making them even harder to spot.
“We now know that just because a person in a video has a measurable pulse, it doesn’t mean that we can assume they are real,” says Hany Farid at the University of California, Berkeley, who was not involved in the research.
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This development comes as deepfakes that have been digitally altered or generated by artificial intelligence are ensnaring celebrities and ordinary people alike in convincing but false pornography, financial scams and political propaganda. Previously, researchers had experimented with spotting deepfakes by identifying changes in skin colour related to blood flow and heart rate, but this research shows that some deepfake videos can still present a passable pulse.
Peter Eisert at the Fraunhofer Institute for Telecommunications in Germany and his colleagues developed a deepfake detector that could analyse the pulses of people in genuine and deepfake videos. They also filmed a new set of genuine videos featuring a dozen people’s facial expressions, while simultaneously recording participants’ heart rates so that they could verify the accuracy of their detector.
Then, the researchers inserted digitally altered faces into their genuine videos – a move that should have alerted their deepfake detector. Instead, they found that the detector perceived realistic pulses in both the fakes and the original videos.