Two studies published on 21 August 2026 arrive at the same finding from opposite directions: a Nielsen Norman Group test where AI and stock hero photos scored the same until a viewer suspected AI, and a Frontiers in Computer Science experiment where watermarking a photo “AI-generated” dented its authenticity score while “human-generated” changed nothing. Neither study found the trust cost sitting in how the image was actually made — it sat entirely in whether the viewer noticed.
The Frontiers paper also turns up a wrinkle its own authors flag: disclosure hurt perceived authenticity but independently helped purchase intent, and the damage barely cleared statistical significance in one of two product categories tested. We walk through the numbers, the counterpoint, and what it means that EU Article 50 has, since 2 August 2026, made noticing mandatory by law rather than by chance.