When Fakes Feel Real: Behavioral and Neural Mechanisms of Deepfake Hyperrealism in Younger and Older Adults

Abstract Deepfakes are designed to mimic real people and constitute an emerging exploitation threat. They are potent methods of fraud as humans detect deepfake images at near or below chance levels, and deepfakes are frequently perceived as more real even than real images (deepfake hyperrealism). Anterior insula (aINS) function is implicated in processing salient, untrustworthy cues suggesting that low aINS recruitment during deepfake perception may underlie experiences of deepfake hyperrealism. Further, aging may confer increased experiences of deepfake hyperrealism, given increased susceptibility to deception and reduced aINS sensitivity to deceptive stimuli with age. Here, 156 participants (62 younger: 18-37 years, 94 older: 60-89 years) evaluated the realness of real and deepfake face images while undergoing fMRI. Behavioral results revealed deepfake hyperrealism in both age groups, with these effects more pronounced in older adults. Our imaging results indicated lower aINS activation was associated with higher realness ratings and aINS activity was also lower for deepfake than real images in both younger and older adults. These findings provide additional support for deepfake hyperrealism in perception, underscoring the threat of deepfakes as a method of exploitation across adulthood. Results also support that muted aINS response to deepfakes constitutes a neuromechanism in deception vulnerability.