Scott Alexander examines recent studies on the Fraternal Birth Order Effect, finding evidence for a broader sibling birth order effect on homosexuality, though its exact nature and mechanism remain debated. Longer summary

Scott Alexander reviews recent studies on the Fraternal Birth Order Effect (FBOE), which suggests that men with more older brothers are more likely to be gay. He discusses three key studies: Frisch and Hviid's large-scale Danish study that found no clear FBOE, Vilsmeier et al.'s meta-analysis that questioned the statistical validity of previous FBOE claims, and Ablaza et al.'s extensive Dutch study that found a significant effect of older siblings (both brothers and sisters) on homosexuality. Scott concludes that while the FBOE hypothesis has been forced to evolve, the core idea that more older siblings increases the likelihood of homosexuality seems to stand, though the biological mechanism remains uncertain. Shorter summary

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

Scott Alexander revisits the birth order effect he discovered in his blog readership in 2018, presenting new data from a 2020 survey. He confirms the original findings that firstborns are overrepresented among his readers, especially when age gaps between siblings are small. The post explores potential explanations, concluding that social factors, particularly parental attention, likely play a larger role than biological factors. This challenges some established views on the impact of early childhood experiences on adult outcomes. Scott acknowledges limitations in his analysis and calls for further research to better understand these effects. Shorter summary

Scott Alexander analyzes a study on lactation fetishes and its critical window theory, using his own survey data to suggest an alternative explanation based on birth order effects. Longer summary

Scott Alexander examines a study by Enquist et al on lactation fetishes, which suggests a critical window theory for fetish development based on exposure during childhood. The study found that lactation fetishists had more younger siblings, seemingly supporting this theory. However, Scott compares this to his own survey data, which shows a similar pattern for intellectual curiosity. He then uses data from the SSC 2019 Survey to test both hypotheses, looking at various fetishes and sibling relationships. The results suggest that having older siblings suppresses fetish formation, rather than younger siblings causing it. This casts doubt on the critical window theory and indicates that birth order effects on openness to experience might better explain the original study's findings. Shorter summary

Scott Alexander presents survey data showing a strong overrepresentation of oldest siblings among his blog readers, challenging the view that birth order effects are negligible. Longer summary

Scott Alexander challenges the mainstream view that birth order effects are negligible, presenting data from his blog survey that shows a strong tendency for oldest children to be overrepresented among his readers. He finds that in families of two children, 71.4% of respondents were the older sibling, with similar patterns in larger families. While he couldn't fully replicate previous studies' findings on IQ differences, he did find a significant difference in Openness to Experience. Scott suggests that birth order may have a stronger effect on intellectual curiosity than previously thought, which could explain the skewed ratios in certain communities. He calls for further research to understand the mechanisms behind this effect and its potential implications. Shorter summary

Scott Alexander preregisters hypotheses for the 2018 SSC Survey, planning to explore relationships between perception, cognition, personality, and demographics. Longer summary

Scott Alexander preregisters his hypotheses for the 2018 SSC Survey. He plans to investigate various relationships between perception, cognition, personality traits, and demographic factors. Key areas of focus include replicating previous findings on perception and cognition, exploring concepts like 'first sight and second thoughts' and 'ambiguity tolerance', investigating birth order effects, and examining correlations with autism, political views, and sexual harassment. He also plans to follow up on a previous AI risk persuasion experiment. Shorter summary