Study reveals people rarely suspect AI in personal messages

Published
Score
17

Why it matters

University of Michigan psychologists Andras Molnar and Jiaqi Zhu conducted two experiments with over 1,300 U.S. adults to measure how people perceive AI-generated personal messages. Participants evaluated AI-written apologies and similar communications across four conditions: no authorship disclosure, human authorship, AI authorship, and uncertain origin. When kept unaware that messages were AI-generated, recipients rated them as genuine and thoughtful—indistinguishable from human-written versions. The moment participants learned AI authored the messages, however, they imposed what the researchers call an "AI disclosure penalty," suddenly viewing senders as lazy and insincere. Notably, frequent AI users showed no greater skepticism by default.

The study found that AI-generated messages effectively mimicked personal writing styles across all participant groups, regardless of their own experience with AI tools. The researchers did not disclose whether certain message types or scenarios triggered greater skepticism than others, nor have they published detailed breakdowns of which demographic groups showed the strongest disclosure penalties. The work builds on earlier research documenting poor human detection of AI text and prior findings that disclosure itself reduces trust in apologies and job applications.

For attorneys advising clients on AI use in business communications, employment matters, or client-facing work, the findings present a practical problem: undisclosed AI use may improve initial reception but carries reputational risk if discovered. The disclosure penalty suggests that transparency about AI authorship—whether in marketing emails, client correspondence, or internal communications—may be legally and strategically preferable to relying on undetected use. As AI integration accelerates in workplace and commercial settings, the gap between perceived authenticity and actual authorship will likely become a material issue in disputes over misrepresentation and good faith dealing.

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