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On whether changes in bedroom CO2 levels affect sleep quality
Self-experiment on whether changes in bedroom CO₂ levels affect sleep quality
Gwern Branwen
Personal website of Gwern Branwen (writer, self-experimenter, and programmer): topics: psychology, statistics, technology, deep learning, anime. This index page is a categorized list of Gwern.net pages.
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Visit gwern.net → RSS feedOn Hacker News Nov 2011 – Sep 2026
Life, Learning & Writing 35Society, Policy & Culture 23Science & Space 23AI & Machine Learning 14Tools & Productivity 13Tech Industry & Business 12
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Nootropics
Notes on nootropics I tried, and my experiments
3
Melatonin
Melatonin improves sleep, & sleep is valuable
4
Everything is correlated (2014–23)
Anthology of sociology, statistical, or psychological papers discussing the observation that all real-world variables have non-zero correlations and the implications for statistical theory such as ‘null hypothesis testing’.
5
Feynman’s Maze-Running Story
Richard Feynman recounts an amazing anecdote about philosophy of science; we trace it to a forgotten University of Michigan research programme into ‘floor cues’.
6
Magnesium Self-Experiments
3 magnesium self-experiments on magnesium ʟ-threonate and magnesium citrate.
7
LSD microdosing: a randomized, blind self-experiment
Self-experiment with sub-psychedelic doses of LSD; no benefit
8
Everything Is Correlated
Anthology of sociology, statistical, or psychological papers discussing the observation that all real-world variables have non-zero correlations and the implications for statistical theory such as ‘null hypothesis testing’.
9
The Neural Net Tank Urban Legend
AI folklore tells a story about a neural network trained to detect tanks which instead learned to detect time of day; investigating, this probably never happened.
10
Nicotine as a useful stimulant
On the benefits and lack of demerits of nicotine (research up to 2015)
11
Algernon's Law
Why most supplements fail: IQ improvement skepticism, Yudkowsky & Bostrom’s heuristics, nootropics
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Nicotine (2016)
On the benefits and lack of demerits of nicotine (research up to 2015)
13
Algernon's Law
Why most supplements fail: IQ improvement skepticism, Yudkowsky & Bostrom’s heuristics, nootropics
14
Complexity No Bar to AI
Critics of AI risk suggest diminishing returns to computing (formalized asymptotically) means AI will be weak; this argument relies on a large number of questionable premises and ignoring additional resources, constant factors, and nonlinear returns to small intelligence advantages, and is highly unlikely.
15
Genetics and Eugenics in Frank Herbert's DUNE
Observations on Frank Herbert’s 𝐷𝑢𝑛𝑒 series—the notes are probably overstated, the Butlerian Jihad was 𝑛𝑜𝑡 a robot uprising seeking to exterminate humanity, and precognition/prescience in the Dune universe appears to work backwards allowing for retro-causality and stable time-loops as exemplified by Leto II’s Golden…
16
Correlation is usually not causation. But why not?
Correlations are oft interpreted as evidence for causation; this is oft falsified; do causal graphs explain why this is so common, because the number of possible indirect paths greatly exceeds the direct paths necessary for useful manipulation?
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Open Questions
Some anomalies/questions which are not necessarily important, but do puzzle me or where I find existing explanations to be unsatisfying.
18
The Existential Risk of Mathematical Error
Mathematical mistake/error-rates limit our understanding of rare risks and ability to defend against them.
19
The Neural Net Tank Urban Legend
AI folklore tells a story about a neural network trained to detect tanks which instead learned to detect time of day; investigating, this probably never happened.
20
Dual N-Back Meta-analysis
Does DNB increase IQ? What factors affect the studies? Probably not: gains are driven by studies with weakest methodology like apathetic control groups.
21
The Scaling Hypothesis (2021)
On GPT-3: meta-learning, scaling, implications, and deep theory. The scaling hypothesis: neural nets absorb data & compute, generalizing and becoming more Bayesian as problems get harder, manifesting new abilities even at trivial-by-global-standards-scale. The deep learning revolution has begun as foretold.
22
The IQ Halo effect
On desirable correlates of intelligence
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Embryo Selection For Intelligence
A cost-benefit analysis of the marginal cost of IVF-based embryo selection for intelligence and other traits with 2016–2017 state-of-the-art.