When the Prompt Speaks Louder than the Person: Output Anchoring in Personality-Informed LLM Emotional Support for Drivers
This Work-in-Progress examines whether personality-informed prompting changes perceived LLM emotional support in driving scenarios designed to elicit stress. A condition-order-balanced, within-subject CARLA simulator study (n = 14) compared a baseline with a Driver Personality Profile (DPP) condition; a supplementary online video pilot (n = 12) examined response perception without driving control or live-system latency. No statistically detectable condition differences emerged for usefulness, ease of use, privacy concerns, or social/emotional presence, and only 7 of 14 simulator participants identified the DPP condition correctly. A post-hoc lexical audit showed that both conditions frequently reused generic supportive scaffolding. We discuss output anchoring as one tentative interpretation, not an established phenomenon: the evidence cannot distinguish constraint-dominated generation from a weak personalization manipulation or limitations of the 7B model. The findings motivate stronger, independently validated personalization manipulations and privacy-aware in-vehicle support.