A review of the synaptic plasticity and memory hypothesis arguing that it is insufficient to explain memory, and proposing a broader cellular processes and memory hypothesis that includes molecular and intracellular mechanisms. Longer summary

The post reviews the synaptic plasticity and memory (SPM) hypothesis, which claims that learning and memory are stored in changes to synaptic weights between neurons. Through several compelling examples, from cannibalism rituals to heart transplant stories and single-cell learning, the author argues that while the SPM hypothesis has been productive, it is incomplete and partially wrong. The post presents evidence that memory can be stored through non-synaptic mechanisms, and proposes an alternative called the cellular processes and memory (CPM) hypothesis, which suggests memory storage involves multiple molecular and intracellular processes beyond just synaptic weights. Shorter summary

Scott explores the 'missing heritability' problem in genetics, where twin studies show traits like IQ and educational attainment are highly heritable but newer genomic methods find much lower heritability, analyzing various potential explanations for this discrepancy. Longer summary

The post examines the 'missing heritability' problem in genetics, where twin studies consistently show behavioral traits like IQ and educational attainment are substantially heritable (around 40-60%), while newer genomic methods find much lower heritability (around 15-20%). Scott reviews the history of behavioral genetics research, explains various study methodologies and their potential biases, and analyzes different hypotheses for this discrepancy. He examines whether twin studies might be flawed, whether newer methods might be missing important genetic effects, and whether educational attainment might be an unusually problematic trait to study. While acknowledging remaining mysteries, he tentatively concludes that twin studies are probably largely correct and that newer methods may be missing rare variants and genetic interactions. Shorter summary

Scott Alexander responds to Robin Hanson's reply on medical effectiveness, clarifying interpretations and reiterating arguments about the limitations of insurance experiments in evaluating medical care. Longer summary

Scott Alexander responds to Robin Hanson's reply to his original post on medical effectiveness. Scott clarifies his interpretation of Hanson's views, discusses potential misunderstandings, and reiterates his arguments about the limitations of insurance experiments in evaluating medical effectiveness. He also addresses specific points Hanson made about cancer treatment, health insurance studies, and p-hacking in medical research. Scott concludes by restating his position that while some medicine is ineffective, it's crucial to distinguish between effective and ineffective treatments rather than dismissing medicine broadly. Shorter summary

Scott Alexander investigates the claim that children learn languages faster than adults, finding it partially true but more nuanced than commonly believed. Longer summary

Scott Alexander examines the claim that children learn languages faster than adults, finding it to be partially true but more complex than commonly believed. He explores various aspects of language acquisition, including critical periods for first language learning, age effects on second language learning, and differences in learning rates between children and adults. The post concludes that while children seem to pick up second languages faster than adults, this advantage is not as clear-cut as often thought, and factors like exposure, motivation, and declining learning rates with age play significant roles. Shorter summary

Scott Alexander explores whether people can be honestly mistaken about their own experiences, presenting counterexamples and attempting to reconcile them with the idea that we can't be wrong about our immediate subjective experiences. Longer summary

Scott Alexander discusses the concept of whether people can be honestly wrong about their own experiences. He initially asserts that people can't be wrong about their own experience, only lying or telling the truth. However, he then explores several counterexamples and edge cases that challenge this view. These include instances of hunger not being consciously felt, time perception on drugs, a woman claiming to be enlightened but unaware of her thoughts, optical illusions, and psychedelic experiences. Scott attempts to reconcile these examples with his initial assertion by differentiating between subjective experiences and underlying realities. He concludes by acknowledging the difficulty in maintaining his original position, while still feeling that there's something fundamentally true about the idea that we can't be wrong about our immediate experiences. Shorter summary

Scott responds to various comments on his article about supplement labeling, addressing concerns about the industry and providing additional context and analysis. Longer summary

This post is a highlights reel of comments on Scott's previous article about supplement labeling. It covers various points raised by commenters, including skepticism about the supplement industry, concerns about heavy metal contamination, and a defense from the founder of LabDoor. Scott responds to each comment, providing additional context, analysis, and sometimes his own perspective on the issues raised. The post touches on topics such as the efficacy of supplements, the trustworthiness of supplement testing companies, and the potential risks associated with certain types of supplements. Shorter summary

Scott Alexander examines obscure pregnancy interventions that may improve child outcomes, rating them by evidence quality and potential impact. Longer summary

Scott Alexander reviews various obscure pregnancy interventions that could potentially improve child outcomes, particularly IQ. He rates them in tiers based on evidence strength and potential impact, with Tier 1 being most strongly supported. Key interventions discussed include embryo selection, choline supplementation, avoiding stress and certain substances, and optimizing birth timing. He emphasizes these are extreme measures not meant to induce guilt, and that standard pregnancy advice is still most important. Shorter summary

Scott Alexander analyzes ivermectin studies for COVID-19, finding most positive results likely due to methodological flaws, fraud, or confounding by parasitic infections. Longer summary

Scott Alexander provides an in-depth analysis of ivermectin studies for COVID-19 treatment, examining methodological issues, potential fraud, and confounding factors. He concludes that ivermectin likely doesn't significantly reduce COVID mortality except potentially in areas with high parasitic worm infections. The post explores broader issues around scientific credibility, fraud detection, and public trust in science. Shorter summary

Scott Alexander examines why certain families produce multiple generations of high achievers, exploring genetic, environmental, and psychological factors. Longer summary

Scott Alexander explores the phenomenon of highly accomplished families, such as the Huxleys, Darwins, and Curies, who have produced multiple generations of notable scientists, artists, and leaders. He discusses potential explanations for this trend, including privilege, genetics, and unique family environments. The post delves into the role of assortative mating, large family sizes, and the correlation between different types of talents. It also touches on the concept of a 'Hero License' - the idea that coming from an accomplished family might instill the confidence to pursue ambitious goals. Shorter summary

Scott Alexander examines the concept of 'light water' and its potential health benefits, critically analyzing various arguments while expressing fascination with this unexpected area of scientific inquiry. Longer summary

Scott Alexander explores the concept of 'light water' (water depleted of deuterium) as a potential health treatment. He begins with a hypothetical scenario about poisoning Castro with heavy water, then explains the science behind isotopes of water. The post discusses various arguments for light water's health benefits, including evolutionary, molecular biology, and oncological perspectives. Scott critically examines these claims, pointing out flaws in some arguments while acknowledging that some cancer studies seem intriguing. He concludes by expressing fascination with the unexpected dimensions along which scientific inquiry can progress, even if the medical benefits of light water remain unproven. Shorter summary

Scott examines data on COVID-19 lockdown effectiveness, finding they likely reduced transmission but at significant costs, with targeted measures being most effective. Longer summary

Scott analyzes the effectiveness of COVID-19 lockdowns, examining data from Sweden, US states, and Europe. He finds that lockdowns likely reduced transmission rates, with targeted measures like school closures being more effective than stay-at-home orders. The analysis suggests lockdowns saved lives but at significant economic and emotional costs, with the cost-effectiveness varying between countries and time periods. Scott concludes that fast, well-targeted lockdowns may have been optimal, but emphasizes the high uncertainty in these estimates. Shorter summary

Scott examines the relationship between sleep, synaptic homeostasis, and depression, exploring how sleep deprivation temporarily alleviates depression symptoms. Longer summary

Scott Alexander discusses a phenomenon where sleep deprivation temporarily alleviates depression, and explores the potential connection between sleep, synaptic homeostasis, and depression. He reviews the synaptic homeostasis hypothesis of sleep, which suggests that sleep helps renormalize synaptic connections, and connects this to research indicating that depression involves a deficit of synapses. The post then delves into various subtopics related to this theory, including the roles of REM and non-REM sleep, the effects of TMS and electroconvulsive therapy, and potential connections to circadian rhythms and bipolar disorder. Shorter summary

Scott Alexander critically evaluates the evidence for Vitamin D's role in COVID-19 prevention and treatment, ultimately leaning towards skepticism while acknowledging the low risk of supplementation. Longer summary

Scott Alexander examines the evidence for and against Vitamin D's effectiveness in preventing or treating COVID-19. He reviews various studies, including observational data, randomized controlled trials, and Mendelian randomization studies. While some evidence suggests a potential link between Vitamin D levels and COVID-19 outcomes, Scott ultimately leans towards skepticism. He discusses possible confounding factors and methodological issues in some of the positive studies. Despite his skepticism, Scott acknowledges the low risk of Vitamin D supplementation and suggests it may still be beneficial for other reasons. Shorter summary

Scott Alexander examines mental disorders through the lens of dynamical systems theory, exploring how this perspective complements and contrasts with taxometric approaches. Longer summary

Scott Alexander explores the concept of mental disorders as dynamical systems with attractor states, contrasting this with the taxometric approach. He uses examples like Alice's health insurance situation and Bob's depression to illustrate how complex systems can have stable states that attract nearby unstable situations. The post discusses how this perspective can help understand the nature of depression and other mental disorders, showing how they can be both dimensional and categorical. Scott also draws parallels between the complexity of mental disorders and the global economy, emphasizing the intricate interconnections and the difficulty of predicting outcomes or effective interventions. Shorter summary

Scott Alexander examines the Amish health care system, which costs much less than the American system while maintaining good health outcomes, and considers its implications for broader healthcare policy. Longer summary

Scott Alexander explores the Amish health care system, comparing it to the modern American system. He notes that the Amish spend much less on healthcare while maintaining good health outcomes, though they have slightly lower life expectancy. The Amish system relies on church aid and a simple insurance-like institution called Amish Hospital Aid. Key factors in their lower costs include collective bargaining, avoiding unnecessary care, not suing doctors, and price-sensitive consumption. Scott considers the applicability of this system to wider society and reflects on how healthcare costs have changed over time, suggesting a possible self-reinforcing cycle between rising costs and the spread of health insurance. Shorter summary

The post argues that automation and AI are unlikely to cause a sustained economic crisis, as new jobs will be created to replace those automated, though the benefits may primarily go to capital owners. Longer summary

This post discusses the potential economic impact of automation and AI, addressing concerns about job displacement and economic crisis. The authors argue that while automation will continue to change the job market, it is unlikely to lead to a sustained economic crisis in the foreseeable future. They examine historical trends in employment, current technological capabilities, and economic theories to support their argument. The post concludes that new jobs will continue to be created as old ones are automated, maintaining overall employment levels, though the benefits of automation may flow primarily to capital owners. Shorter summary

A vegetarian and meat-eater collaborate to analyze the impacts of eating meat, concluding that reduced consumption is beneficial but not as clear-cut as some might think. Longer summary

This post is an entry to the 2019 Adversarial Collaboration Contest, where a vegetarian and a meat-eater investigate the ethical, health, and environmental impacts of eating meat. They explore animal consciousness, factory farming conditions, human happiness set points, health outcomes, environmental effects, and costs of switching diets. They conclude that reducing meat consumption, especially chicken, is beneficial overall, but the case is not as strong as some vegetarians might assume. Shorter summary

The post examines the medical benefits, risks, and ethical considerations of infant circumcision, presenting a balanced view based on various studies and historical context. Longer summary

This post discusses the benefits, harms, and ethics of infant circumcision. It covers various aspects including effects on penile cancer, HIV and STD transmission, UTIs, penile problems, and surgical risks. The authors also examine the impact on sensitivity and sexual satisfaction, and discuss the ethical considerations of performing this procedure on infants. The post presents a balanced view, citing numerous studies and historical context, and acknowledges the complexity of the ethical debate surrounding infant circumcision. Shorter summary

A diverse collection of links to interesting articles, studies, and news items on topics ranging from history and science to politics and culture. Longer summary

This post is a collection of links to various interesting articles, studies, and news items. It covers a wide range of topics including Russian city flags, archaeological hoaxes, growth mindset research, atomic gardening, AI takeoff scenarios, UFO patents, antibiotic resistance, freelance journalism laws, religious trends in the Middle East, presidential candidate support by occupation, civility in politics, pollution comparisons, open borders debates, gender reveal party accidents, historical theories about Western psychology, entrepreneurship age trends, socialist proposals, WWI myths, biological feedback mechanisms, and various other curiosities and current events. Shorter summary

Scott Alexander examines the paradoxical relationship between autism and intelligence, discussing genetic and environmental factors, and proposing explanatory models for the observed lower IQ in autistic individuals despite genetic links to higher intelligence. Longer summary

Scott Alexander explores the paradoxical relationship between autism and intelligence. While genetic studies show a link between autism risk genes and high IQ, autistic individuals generally have lower intelligence than neurotypical controls. The post discusses three main causes of autism: common 'familial' genes that increase IQ, rare 'de novo' mutations that are often detrimental, and non-genetic factors like obstetric complications. Scott examines various studies and proposes that even after adjusting for mutations and environmental factors, autism still seems to decrease IQ. He introduces a 'tower-vs-foundation' model to explain this phenomenon, where intelligence needs a strong foundation to support it, and an imbalance can lead to autism. The post concludes with a list of findings and their associated confidence levels. Shorter summary

Scott Alexander investigates the prevalence of Hallucinogen Persisting Perceptual Disorder (HPPD) and explores potential connections between perception, cognition, and belief in supernatural phenomena. Longer summary

Scott Alexander explores the prevalence and nature of Hallucinogen Persisting Perceptual Disorder (HPPD), a condition where people experience ongoing visual disturbances after using psychedelics. He discusses results from his own survey, which found that about 12.8% of psychedelic users reported some persisting hallucinations, with 3% still experiencing them. Most cases were mild, involving visual snow, halos, or patterns. Scott then critiques a study claiming HPPD doesn't exist, noting methodological issues. He also considers the possibility that some people naturally experience HPPD-like phenomena without drug use, and speculates on potential links between perception, cognition, and belief in supernatural phenomena. Shorter summary

Scott examines studies linking sleeping pills to increased mortality, highlighting a new study that found no link after adjusting for 300 confounders, potentially challenging the validity of less thorough studies. Longer summary

Scott Alexander discusses a controversial topic in medical research: the link between sleeping pills and increased mortality. He reviews several studies that found a strong association between sleeping pill use and higher death rates from various causes, even after controlling for confounders. However, he then introduces a new study by Patorno et al. that found no such link for benzodiazepines. The key difference is that this study adjusted for an unprecedented 300 confounders using a new statistical algorithm. Scott suggests that if this study is correct, it could mean that many other medical studies that only control for a handful of confounders might be inadequate. He draws parallels to other fields where dramatically increasing scale or intensity has led to new insights. Shorter summary

A diverse collection of news items and interesting links covering science, technology, politics, and culture, with brief commentary on each. Longer summary

This post is a collection of interesting links and news items from various fields. It covers topics such as animal behavior, space exploration, technology, politics, environmental issues, and scientific research. The post includes brief summaries or commentary on each item, often with a touch of humor or personal reflection. Some notable items include the story of the Soviet space shuttle Buran, a new California law on pet shops, developments in AI and cryptocurrency, and concerns about insect population decline. The post also touches on social issues like racial approval ratings for Trump and the controversial Gillette commercial. Shorter summary

Scott Alexander critically examines studies on preschool effects, finding mixed and inconsistent evidence for long-term benefits. Longer summary

Scott Alexander reviews multiple studies on the long-term effects of preschool programs like Head Start. While early studies showed fade-out of test score gains, some found lasting benefits in adult outcomes. However, Scott finds inconsistencies between studies in which subgroups benefit and on which outcomes. He also notes concerns about potential p-hacking and researcher degrees of freedom. Ultimately, Scott concludes that the evidence is mixed - it permits believing preschool has small positive effects, but does not force that conclusion. He estimates 60% odds preschool helps in ways suggested by the studies, 40% odds it's useless. Shorter summary

The post explores how correlated variables can diverge at extreme values, applying this concept to happiness measures and moral systems. Longer summary

This post explores the concept of 'tails coming apart' and its application to various domains, particularly morality. The author begins by discussing how strongly correlated variables can diverge at extreme values, using examples like grip strength vs. arm strength. He then applies this concept to happiness, showing how different measures of happiness (e.g., life satisfaction, positive emotions) can lead to different countries being ranked as 'happiest'. The post extends this idea to morality, arguing that while different moral systems may agree in everyday situations, they diverge dramatically when taken to extremes. The author suggests that this divergence poses challenges for developing moral systems that can handle transhuman scenarios. Shorter summary