Scott explores how acetylcholine-related cognitive enhancers might work by increasing sensory precision and learning rate, while speculating on potential tradeoffs and acknowledging the highly speculative nature of these ideas. Longer summary

This post explores the mechanisms and potential tradeoffs of cognitive enhancers, focusing on acetylcholine-related substances like piracetam and nicotine. Scott discusses the role of acetylcholine in the brain's predictive coding model, where it's thought to increase sensory precision and learning rate. He speculates on how this might explain the cognitive-enhancing effects of these drugs, but also considers potential downsides like disrupted intuitive understanding or increased risk of psychotic-like thinking. The post ends by acknowledging the highly speculative nature of these ideas and noting some contradictory evidence. Shorter summary

Scott Alexander reports on a survey of nootropics users, finding mixed results for various substances and discussing methodological challenges in assessing their effectiveness. Longer summary

Scott Alexander presents the results of a survey on nootropics, substances claimed to improve mental functioning. The survey, taken by 162 respondents from online nootropics communities, asked about experiences with 28 different substances. Key findings include: caffeine and modafinil were rated most effective; some newer substances like phenylpiracetam and coluracetam showed promise; traditional medicines had mixed results; dose-response relationships were mostly inconclusive except for high-dose vitamin D; and there were unexpected correlations between effects of different substances. Scott discusses limitations of the survey and plans for future iterations. Shorter summary