This study explores how human moral value systems can influence the general reasoning and problem-solving abilities of Large Language Models (LLMs). While existing research in AI ethics has primarily treated morality as a constraint for ensuring m...
This study explores how human moral value systems can influence the general reasoning and problem-solving abilities of Large Language Models (LLMs). While existing research in AI ethics has primarily treated morality as a constraint for ensuring model safety, this thesis extends its role to a cognitive function, empirically analyzing how moral conditioning can alter the model’s reasoning patterns and decision-making processes.
Drawing on Kohlberg's theory of moral development, this study defines three moral conditions aligned with the theory's three stages. Through moral conditioning prompts designed to reflect the core moral values and decision rules of each stage, models are guided to adopt the corresponding patterns of moral reasoning. The validity of this moral alignment is verified using the Defining Issues Test, a psychological assessment tool that measures moral judgment maturity. Models under different moral conditions are then evaluated on the MMLU benchmark.
Experimental results demonstrate that moral perspectives induce meaningful changes in the model’s general reasoning processes. Models conditioned to reflect more advanced moral values exhibit greater self-reflective reasoning and provide more concrete justifications in their responses, which in turn leads to improved MMLU performance. These patterns are consistently observed in additional experiments designed to evaluate the generalizability of moral conditioning effects. Specifically, experiments that vary the surface form of the moral-conditioning prompts, as well as experiments that apply training-based conditioning methods such as Supervised Fine-tuning (SFT) and Direct Preference Optimization (DPO), show that the model reliably reproduces the intended moral reasoning patterns, with corresponding improvements in MMLU performance. Layer-wise analyses of hidden representations further reveal that higher-level moral conditioning induces larger internal changes during the reasoning process. These internal shifts align with the observed performance gains, suggesting that moral conditioning influences not only the model’s explicit outputs but also its internal representations and information-processing mechanisms.
By examining the cognitive role of moral values, this study demonstrates their potential influence on the general reasoning ability of LLMs. This perspective moves beyond treating morality as merely a safety constraint, revealing it as a factor that can shape the model's reasoning processes.