Confirmation, Framing, and Position Biases in LLM Responses

Large Language Models (LLMs) exhibit remarkable generative and reasoning capabilities, yet their outputs often reflect systematic cognitive biases analogous to those observed in human judgment. This paper investigates three interrelated forms of bias: confirmation bias, position bias, and framing bias. Through a series of controlled prompting experiments, we demonstrate that LLMs tend to reinforce the premises embedded in user queries (confirmation bias), favor initial or prominent elements within a prompt (position bias), and vary their conclusions depending on the positive or negative framing of the input (framing bias). We analyze these effects across different open LLMs: Qwen, Mistral, Gemma, Olmo, and LLama. These insights can inform better prompt engineering practices, strengthen evaluation benchmarks, and support the responsible use of LLMs in education, research, and decision-making.