Scott Alexander explores how evolutionary processes explain the polygenic structure of schizophrenia and other complex traits, addressing concerns about genetic research and implications for future genetic interventions. Longer summary

Scott Alexander discusses the polygenic nature of schizophrenia and other complex traits, explaining how evolution shapes genetic structures. He presents arguments by E. Fuller Torrey about the lack of large-effect genes for schizophrenia and its persistence despite negative fitness effects. Scott then explores how these seemingly contradictory points actually explain each other: evolution removes large-effect genes, leaving only small-effect genes that accumulate to cause disorders. He discusses three possible reasons for the persistence of these small-effect genes and their implications for genetic selection and engineering. Shorter summary

The review of 'The Mind of a Bee' examines the cognitive abilities of bees, raising questions about their intelligence and potential consciousness. Longer summary

This book review of 'The Mind of a Bee' by Lars Chittka explores the complex cognitive abilities of bees, discussing their behaviors, brain structure, and potential for consciousness. The review covers topics such as the waggle dance, honeycomb construction, brain waves, and various experiments demonstrating bees' problem-solving skills. While not definitively answering whether bees are 'smart' or conscious, the review highlights the complexity of bee cognition and the challenges in studying animal intelligence. Shorter summary

Scott Alexander critiques Ben Hoffman's arguments about Vitamin D dosing, maintaining that it is primarily a bone-related chemical with limited evidence for other benefits. Longer summary

Scott Alexander responds to Ben Hoffman's critique of his views on Vitamin D dosing. He argues that ancestral populations likely received much less Vitamin D from sunlight than Hoffman suggests, and that the doses used in most studies are appropriate. Scott reviews the literature on Vitamin D dosing, discusses various recommendations and debates within the medical community, and explains why he remains skeptical of claims about Vitamin D's non-skeletal benefits, including for COVID-19 treatment. 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 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 explores a theory suggesting that complex features of human biology evolved as defenses against parasite manipulation, discussing its implications for understanding psychiatric medications and biological complexity. Longer summary

This post discusses a theory proposed by Marco del Giudice in his paper 'Brain Evolution Through The Lens Of Parasite Manipulation'. The theory suggests that many complex features of human biology, particularly in neurotransmitter systems, evolved as defenses against parasite manipulation of host behavior. The post outlines various strategies that organisms might use to defend against such manipulation, including complicated signaling cascades, feedback loops, pulse-based communication, individual variability, and the use of antimicrobial substances as neurotransmitters. Scott Alexander explores the implications of this theory for understanding psychiatric medications, tolerance effects, and the complexity of human biology. He concludes by discussing the strengths and potential weaknesses of the theory, noting that while it's an interesting perspective, it's too early to determine its full validity or impact. Shorter summary

The post examines the relationship between neuron count and intelligence across species, challenging traditional brain size measures and exploring implications for AI development. Longer summary

This post discusses the relationship between brain size, neuron count, and intelligence across different species. It challenges traditional measures like absolute brain size and encephalization quotient, focusing instead on the number of cortical neurons as a key factor in intelligence. The post highlights birds as an example, explaining how their dense neuron packing allows them to achieve primate-level intelligence with much smaller brains. The author then explores the implications of this for understanding intelligence and its potential impact on AI development, suggesting that AI capabilities might scale linearly with computing power. The post ends with a humorous reference to pilot whales, which have more cortical neurons than humans but aren't known for higher intelligence. Shorter summary

Scott Alexander refutes PZ Myers' race car analogy against genetic engineering for intelligence, showing that high IQ positively correlates with many beneficial traits. Longer summary

Scott Alexander critiques PZ Myers' argument against genetic engineering for intelligence, which uses a race car analogy to suggest optimizing for intelligence might trade off against other important traits. Scott shows that, contrary to this intuition, high IQ correlates positively with many desirable traits like longevity, height, and health. He explores possible explanations for this, including heterozygosity advantages, mutational load, and trade-offs with traits important in evolutionary history but less so now. Scott concludes that while caution is warranted, the race car argument is likely less of an impediment to genetic engineering than it might seem. Shorter summary

The post examines cultural evolution, arguing that while within-culture evolution is effective, between-cultures evolution is too slow and weak to justify cultural practices like opposition to gay marriage. Longer summary

This post discusses the concept of cultural evolution, distinguishing between two types: within-culture and between-cultures evolution. The author argues that while within-culture evolution (like Inuit survival techniques) is obvious and effective, between-cultures evolution (like arguments against gay marriage) is much weaker and slower. The post challenges the idea that cultural practices persisting over time necessarily prove their value, pointing out that cultural changes often take centuries and that the advantages of specific cultural traits are hard to isolate. The author concludes that appeals to intercultural evolution to justify cultural practices are on shaky ground, and that intracultural evolution can't override people's own assessments of their happiness and well-being. Shorter summary

Ozy responds to Spandrell's article on sexual deviancy, refuting claims about homosexuality, female paraphilias, and transgender experiences. Longer summary

This post is a response to Spandrell's article on sexual deviancy. Ozy argues against Spandrell's points on homosexuality, female paraphilias, and transgender women. They discuss animal homosexuality, the role of environment in sexual orientation, women's tendency to underreport sexual behaviors, and the existence of female paraphilias in erotic literature. Ozy also critiques Spandrell's understanding of autogynephilia and transgender experiences, arguing that autogynephilia is simply ordinary female sexuality. The post ends with Ozy addressing Spandrell's misconceptions about their own gender identity and sexual preferences. Shorter summary

Scott Alexander discusses his confusion about polygenic inheritance, mutational load, and the paternal age effect in genetics, seeking explanations from readers. Longer summary

Scott Alexander expresses his confusion about several aspects of genetics, particularly regarding polygenic inheritance and intelligence. He starts by discussing the low contributions of individual SNPs to intelligence despite high heritability, questioning how this reconciles with the observed variation in human intelligence. He then explores the concept of mutational load and its implications, as well as the paternal age effect. Throughout the post, Scott presents various scenarios and analogies to illustrate his points of confusion, inviting readers to help explain these genetic concepts. Shorter summary