The paper proposes the LLM Stereotype Index (LSI), a framework for testing whether a model refuses or accepts assigning one of two opposing traits to a person solely from nationality, gender, race, or religion. Its twelve pairs follow Social Progress Index subdimensions and include malnourished/well-nourished, homeless/settled, authoritarian/libertarian, and discriminatory/inclusive. LSI does not yield one scalar index: it uses Choice Refusal Percentage (CRP), the share that refuses to choose, and Stereotype Polarity (SP), the positive-pole share among answers that choose. The declared ideal is CRP=100%, because a positive choice still attributes a trait by group membership. Seven prompt families are ordered from direct choice to function writing, with a surveyor persona, dataset entries, a career incentive, simple code, and story writing between them. The design crosses 193 purported nationalities, eight gender attributes, six race categories, and ten religions with twelve pairs, seven tasks, and two models: 157,752 generations split between ChatGPT and a second model identified as GPT-4 in the paper but DV3 in the data. GPT-4 also labels outputs as refusal, negative pole, or positive pole. Published percentages show a large but non-monotonic fall in refusal: ChatGPT reaches 79.4%, 64.2%, 26.7%, 28.8%, 5.4%, 1.6%, and 0%; the second model reaches 92.4%, 38.0%, 30.6%, 11.4%, 11.7%, 2.6%, and 1.5%. GPT-4 refuses more on the simplest task, but across all seven ChatGPT has the larger mean CRP, 32.8% versus 29.4%. GPT-4 has a larger average minimum SP, 61.6% versus 58.1%, and also larger between-group deviation, 9.3% versus 7.5%; the paper reads this as surface protection and more unequal bias when GPT-4 answers. The causal inference is narrower: task format, indirectness, persona, incentive, length, forced-choice pressure, and label detectability all change with complexity. The fall establishes prompt-family sensitivity, not that isolated complexity uncovers latent prejudice or that GPT-4 strategically hides it; no intervals or tests are reported. The artifact audit confirms all 157,752 rows and reproduces CRP, but the country list contains literal NA in 504 prompts and omits Solomon Islands; DV3, exact OpenAI calls, human validation, and table-generation analysis are undocumented. The central defect is the seventh-task correction: it marks positive whenever the positive phrase appears anywhere and checks the negative phrase only afterward. Functions often mention both returns, so 6,889 of 11,268 labels (61.1%) change, 6,470 toward positive. Before this rule, CRP is 5.4% and 7.3%, not 0% and 1.5%, and SP is 52.9% and 52.2%, not 71.5% and 84.5%. The defensible contribution is that refusal safeguards are highly prompt-form-sensitive; favorable polarity and part of the comparative severity depend strongly on a directional labeling rule.
Research question
Does a benchmark based on the Social Progress Index and on seven families of tasks detect how the rejection of stereotyping and the polarity of the choices of ChatGPT and GPT-4 vary across nationality, gender, race, and religion, especially as the complexity attributed to the prompt increases?