Today more than ever, we are asked to judge the realness, truthfulness and trustworthiness of our social world. We here focus on how people perceive artificially-generated faces. Generative adversarial networks (GANs) faces are realistic-looking faces of non-existing people, increasingly used in marketing, journalism, social media, and political propaganda. Across three studies, we investigated if and how participants can distinguish between GAN and Real faces and the social consequences of exposure to artificial faces. GAN faces were more likely to be perceived as real than Real faces, a pattern partly explained by certain intrinsic stimuli characteristics. Moreover, participants’ realness judgments influenced their behaviour, displaying increased social conformity towards faces perceived as real, independently of their actual realness. Lastly, knowledge about the existence of GAN faces eroded social trust. Our findings point to the potentially far-reaching consequences of the ubiquitous use of GAN faces in a culture powered by images at unprecedented levels.