Who Made This Ad in the AI Era? Unpacking AI and Human Authorship Disclosure Effects

As generative AI becomes increasingly common in advertising, disclosure of its use is required in some regions and countries. Prior research shows that AI authorship disclosure can harm consumer responses, but less is known about how explicit authorship disclosure shapes source attribution, whether human authorship disclosure generates positive effects, and how these effects vary across advertising contexts. We conducted three experiments manipulating actual authorship (AI vs. human) and disclosure (disclosed vs. undisclosed) using closely matched AI-generated and human-crafted ads. Study 1 focused on product-centered luxury brand ads, Study 2 on luxury brand ads featuring models, and Study 3 on small-business sponsored posts featuring models. Across all three studies, disclosing AI authorship (vs. no disclosure) consistently produced negative indirect effects on brand attitude through lower perceived effort. By contrast, the effects of disclosing human authorship (vs. no disclosure) varied by context: it had no downstream effect in Study 1; it increased perceived emotion expression without affecting brand attitude in Study 2; and it produced a positive indirect effect on brand attitude in Study 3 through perceived effort. These findings highlight the role of explicit disclosure in shaping source attribution and suggest that AI disclosure and human disclosure can trigger distinct consumer responses across contexts.