Researchers propose the 'LLM Brain Rot Hypothesis', which suggests that large language models (LLMs) can experience cognitive decline when exposed to low-quality, engaging content. The study found that LLMs trained on 'junk' data, such as sensationalized social media posts, performed worse on reasoning and long-context understanding tasks. The decline was persistent even after mitigation strategies were applied. The findings highlight the importance of careful data curation and quality control in LLM training.