This dataset tests whether the serial position (primacy) effect found in JSON-formatted LLM elicitation generalizes to other response formats (natural language, Likert, ranking). A methodological contribution applicable to all LLM-as-respondent research. Records 2,400 calls (2,351 valid, 98.0%) across 4 response formats x 8 Latin-square orderings x 5 focal brands x 5 LLM… See the full description on the dataset page: https://huggingface.co/datasets/spectralbranding/exp-primacy-generalization.