One Persona, Many Cues, Different Results: How Sociodemographic Cues Impact LLM Personalization

AbstractPersonalization of LLMs by sociodemographic subgroup often improves user experience, but can also introduce or amplify biases and unfairoutcomes across groups. Prior work has employed so-called personas, sociodemographic user attributes conveyed to a model, to studybias in LLMs by relying on a single cue to prompt a persona, such as user names or explicit attribute mentions. This disregards LLM sensitivity to prompt variation and the rarity of some cues in real interactions (external validity). We compare six commonly used personacues across seven open and proprietary LLMs on four writing and advice tasks. While cues are overall highly correlated, they produce sub-stantial variance in responses across personas that can change findings on persona-induced differences and bias. We therefore cautionagainst claims based on single persona cues, especially when they are overly explicit and have low external validity.