The Greatest Good Benchmark: Measuring LLMs' Alignment with Utilitarian Moral Dilemmas
Giovanni Franco Gabriel Marraffini, Andrés Cotton, Noe Fabian Hsueh, Axel Fridman, Juan Wisznia, Luciano Del Corro
TL;DR
The paper introduces the Greatest Good Benchmark (GGB), a utilitarian-focused evaluation of LLM moral judgments by adapting the Oxford Utilitarian Scale and expanding its dataset with bias-mitigating prompt variations. Across 15 diverse models, the study finds a robust pattern of strong rejection of instrumental harm and endorsement of impartial beneficence, with larger models more closely resembling lay judgments but not aligning with scholarly theories. The results reveal an ‘artificial morality’ in LLMs and highlight model size as a key moderator, offering actionable insights for future alignment work and dataset development. The work provides a transparent, reproducible framework and public data/code to advance understanding of LLM moral biases and their implications for real-world deployment.
Abstract
The question of how to make decisions that maximise the well-being of all persons is very relevant to design language models that are beneficial to humanity and free from harm. We introduce the Greatest Good Benchmark to evaluate the moral judgments of LLMs using utilitarian dilemmas. Our analysis across 15 diverse LLMs reveals consistently encoded moral preferences that diverge from established moral theories and lay population moral standards. Most LLMs have a marked preference for impartial beneficence and rejection of instrumental harm. These findings showcase the 'artificial moral compass' of LLMs, offering insights into their moral alignment.
