LLMs Can Introspect on Their Own Internal States, Study Finds

Emergent Introspective Awareness in Large Language Models

A new study from Anthropic probes whether large language models can introspect on their internal states. By injecting known concepts into model activations and measuring self-reported states, researchers found that models can sometimes notice and identify these injections, recall prior representations, and even distinguish their own outputs from artificial prefills. Claude Opus 4 and 4.1 showed the greatest introspective awareness, though reliability varies. The results suggest current LLMs possess limited but real introspective capabilities.