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

A review of 'The Family That Couldn't Sleep' by D. T. Max, discussing its exploration of prion diseases and their impact, with updated perspectives on the book's conclusions. Longer summary

This review discusses 'The Family That Couldn't Sleep' by D. T. Max, a book about prion diseases published in 2006. The review covers the book's exploration of various prion diseases, including fatal familial insomnia, kuru, mad cow disease, and chronic wasting disease. It highlights the book's focus on the historical, scientific, and cultural aspects of these diseases, as well as the key figures involved in prion research. The reviewer also provides updated information and critiques some of the book's conclusions in light of more recent research. Shorter summary

A review of 'Viral' by Chan and Ridley explores competing hypotheses about COVID-19's origins, critiquing institutional responses and emphasizing ongoing uncertainty. Longer summary

This book review discusses 'Viral' by Alina Chan and Matt Ridley, which explores the origins of the COVID-19 pandemic. The reviewer summarizes key points from the book, including evidence for both natural and lab leak hypotheses, the history of lab leaks, the relevance of Wuhan's location, and criticisms of institutional responses. The review also covers technical evidence and debates around it, while emphasizing the reviewer's uncertainty about the pandemic's true origin. The author concludes by reflecting on the role of amateur researchers and the importance of scientific self-correction. Shorter summary

Scott Alexander argues against Gary Marcus's critique of AI scaling, discussing the potential for future AI capabilities and the nature of human intelligence. Longer summary

Scott Alexander responds to Gary Marcus's critique of AI scaling, arguing that current AI limitations don't necessarily prove statistical AI is a dead end. He discusses the scaling hypothesis, compares AI development to human cognitive development, and suggests that 'world-modeling' may emerge from pattern-matching abilities rather than being a distinct, hard-coded function. Alexander also considers the potential capabilities of future AI systems, even if they don't achieve human-like general intelligence. Shorter summary

Scott Alexander critically examines a new theory on antidepressant mechanisms, expressing skepticism while acknowledging its potential significance if proven true. Longer summary

Scott Alexander reviews a recent study proposing a new theory for how antidepressants work, which suggests they bind directly to TrkB receptors rather than acting through serotonin. He explains the study's findings and their potential implications, but expresses skepticism about the theory. Scott outlines several reasons why he finds the new theory unconvincing, including existing evidence supporting the serotonin hypothesis, issues with the study's claims about drug accumulation, and expert opinions on the difficulties of TrkB research. He concludes by stating he will stick with the conventional theory for now, while remaining open to future developments. Shorter summary

Scott Alexander maintains a list of significant mistakes in his blog posts, providing corrections and updates in reverse chronological order. Longer summary

Scott Alexander maintains a list of significant mistakes he has made in his blog posts, providing corrections and updates. He acknowledges errors in data interpretation, misunderstandings of studies, incorrect predictions, and instances where he changed his mind based on new evidence or reader feedback. The list is presented in reverse chronological order and covers a wide range of topics including medicine, economics, psychology, and social issues. Shorter summary

This post examines the pros and cons of using gene editing technologies in humans, discussing scientific, medical, and ethical considerations. Longer summary

This post discusses the potential uses, risks, and ethical implications of gene editing technologies in humans. It covers the science behind CRISPR, its safety and efficiency, the relationship between genetics and disease, and potential applications in treating conditions like cancer and HIV. The authors explore complex questions around genetic enhancement and 'designer babies', highlighting both the promise and perils of this technology. They conclude that while gene editing holds great potential, especially for certain genetic diseases, its use must be carefully regulated and ethically considered. 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

A diverse collection of links covering history, science, politics, culture, and curiosities, presented with humor and interesting facts. Longer summary

This post is a collection of various links and interesting facts across multiple domains. It covers historical peace treaties, scientific research on diminishing returns in science, geopolitical tensions in Eurovision, education rankings, religious schisms, marijuana regulations, scientific publishing news, experimental archaeology, neuroscience discoveries, geographical facts, international disputes, philosophy humor, rationality-related subreddits, healthcare transparency efforts, academic scandals, mathematical breakthroughs, political trends, cultural oddities, and linguistic curiosities. The post maintains a light, often humorous tone while presenting a wide array of information. Shorter summary

Scott Alexander explores Hallucinogen Persisting Perception Disorder (HPPD) and other conditions where drugs cause permanent effects, discussing potential mechanisms and their implications. Longer summary

Scott Alexander discusses Hallucinogen Persisting Perception Disorder (HPPD), a condition where some people experience permanent hallucinatory effects after using psychedelic drugs, particularly LSD. He explores the prevalence, potential mechanisms, and implications of this disorder. The post compares HPPD to other conditions with persistent effects like tardive dyskinesia, and examines various theories about how drugs could cause permanent changes in the brain. Scott considers two main hypotheses: the killing-off of specific neurons, and the idea of the brain as a chaotic system settling into new attractor states. He expresses a preference for the neuron death theory as it seems more understandable and less scary, but acknowledges the complexity and uncertainty surrounding these issues. Shorter summary

Scott Alexander shares a diverse collection of links and brief commentaries on topics ranging from ancient calendars to fusion research, social trends, and economic analyses. Longer summary

This post is a collection of links and brief summaries on various topics, including calendar systems, scientific studies, social trends, economics, politics, and technology. Scott Alexander covers a wide range of subjects, from an ancient Persian calendar to fusion power research, social psychology effects, philosophical hiring biases, and economic analyses. The post includes commentary on recent news, scientific findings, and cultural phenomena, often with a touch of humor or skepticism. Shorter summary

The post reviews research on adult neurogenesis, initially presenting evidence for its existence and importance, then reveals a new study suggesting it doesn't occur in humans, examining the implications of this potential field-wide error. Longer summary

This post reviews the literature on adult neurogenesis, initially presenting numerous studies that claimed to find evidence for the generation of new neurons in adult human brains. These studies linked adult neurogenesis to various aspects of brain function, including memory, learning, and depression. However, the post then reveals a new study suggesting that adult neurogenesis doesn't actually occur in humans, or is so rare as to be insignificant. The author examines how this field-wide error could have occurred, discussing the extrapolation of rat studies to humans and the role of confirmation bias. The post ends by reflecting on the implications of this for scientific research and the replication crisis. Shorter summary

Scott examines the phenomenon of Hungarian scientific geniuses in the early 20th century, attributing it to a high concentration of high-IQ Ashkenazi Jews in Budapest rather than exceptional education. Longer summary

Scott explores the phenomenon of Hungarian scientific geniuses in the early 20th century, initially attributed to exceptional education. He debunks this theory, showing that many of these geniuses were prodigies before formal schooling. Scott then reveals that all these geniuses were Jewish, linking their success to the high IQ of Ashkenazi Jews as explained by Cochran, Hardy, and Harpending's theory. He notes that Hungary, particularly Budapest, had an unusually high concentration of Jews at that time. The post concludes by discussing the tragic end of this golden age due to the Holocaust, and speculates on whether we've lost something unique from that era of scientific progress. Shorter summary

A Links post presenting various news items and articles, ranging from cultural curiosities like the multiocular O to scientific findings about brain sex differences and genetic research, along with commentary on current events and politics. Longer summary

Scott Alexander presents a collection of interesting links and articles covering a wide range of topics. The post includes scientific findings (like research on sex differences in the brain and studies on antidepressants), cultural curiosities (like rare Cyrillic letters), political developments (like the White House's decision on Exxon drilling rights), and various technological advances (like an AI that writes poetry). The post provides brief commentary on each link, often with Scott's characteristically analytical and sometimes humorous perspective on the implications of each item. Shorter summary

Scott Alexander defends psychiatry's use of 'chemical imbalance' theory, arguing it was meant to emphasize depression's biological basis rather than claiming a simple serotonin deficiency. Longer summary

Scott Alexander responds to criticisms of psychiatry's use of the 'chemical imbalance' theory of depression. He argues that psychiatrists never claimed depression was simply a serotonin deficiency, but rather a complex interaction of brain chemicals. He explains that the term 'chemical imbalance' was used to emphasize depression's biological basis and help people take it seriously, rather than viewing it as a personal failure. Scott provides evidence that serotonin and other neurotransmitters are indeed involved in depression, while acknowledging the full picture is more complicated. He concludes that framing depression in terms of brain chemistry remains useful, even if 'chemical imbalance' is no longer the best terminology. Shorter summary

Scott shares and comments on various interesting links covering topics like international relations, medical research, technology, and social issues, mixing academic discussion with curious anecdotes. Longer summary

This is a links post where Scott Alexander shares various interesting links he found, with brief commentary on each. The links cover diverse topics from North Korea's Twitter account to medical research about nutrition, and from academic gender studies to technological development. Scott provides context and sometimes critique for the linked articles, maintaining a mix of serious academic discussion and lighter curiosities. Shorter summary

Scott shares a diverse collection of links and brief commentaries on scientific studies, political news, cultural phenomena, and personal observations across various fields. Longer summary

This post is a collection of links and brief commentaries on various topics, including scientific studies, political news, and cultural phenomena. Scott covers a wide range of subjects, from the effects of ultraviolet radiation on weight gain to the decline of cults, global inequality trends, genetic links to violent crime, and the concept of competitive governance. He also discusses recent political events, media controversies, and developments in artificial intelligence research. The post includes personal observations, book recommendations, and reflections on social dynamics within online communities. Shorter summary