Scott shares humorous anecdotes about the daily chaos of raising toddler twins, from emergency police visits triggered by screaming over the wrong version of a song, to elaborate bedtime battles and the children's obsession with identifying vehicles and animals.

Scott examines a new genetic study on missing heritability that both hereditarians and nurturists claim vindicates their position, concluding that despite the study's advances, the fundamental debate over how heritable traits like IQ actually are remains unresolved.

Scott Alexander refutes Stephen Skolnick's theory that schizophrenia is caused by gut microbes rather than genetics, showing why the evidence better supports schizophrenia being a complex genetic neurodevelopmental disorder.

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.

Scott Alexander uses simulations to explain why seemingly counterintuitive arguments against the genetic basis of schizophrenia are misleading.

Scott Alexander explores new data on birth order effects among his blog readers, finding social factors likely explain firstborns' overrepresentation.

Scott Alexander discusses a study challenging the idea that childhood abuse lowers IQ, and explores its implications for understanding the effects of child abuse on various outcomes.

Scott examines conflicting evidence on whether humans choose mates based on parental imprinting or genetics, concluding that mate choice might be based on mysterious romantic love.

The post argues that 'non-shared environment' in twin studies is often misunderstood, encompassing more than just different experiences and potentially overestimating the impact of nurture on personality and life outcomes.

Scott Alexander defends the validity of intelligence and IQ tests by comparing them to comas and the Glasgow Coma Scale in medicine.