Scott Alexander reviews the evidence for declining sperm counts, discussing major studies, criticisms, and potential causes, while remaining uncertain about the true extent and reasons for any decline. Longer summary

Scott Alexander examines the evidence for declining sperm counts worldwide, discussing the major studies, potential causes, and criticisms of the hypothesis. He explores the methodology of sperm count studies, regional variations, possible explanations like plastics and pesticides, and animal data. While acknowledging the noisy data and potential confounders, he concludes that there's suggestive evidence for a decline but remains uncertain about its magnitude and causes. Shorter summary

Scott Alexander compares two contrasting models of how social movements gain or lose respectability, using examples from gay rights and environmental issues to explore their implications. Longer summary

Scott Alexander explores the concept of 'respectability cascades' in social movements, comparing two contrasting models. The first model, exemplified by the gay rights movement, suggests that when less respectable individuals publicly support a cause, it gradually becomes more acceptable for increasingly respectable people to join. The second model, illustrated by issues like endocrine disruptors and immigration, suggests that when disreputable people champion a cause, it becomes toxic and respectable people avoid it. Scott discusses the strategic implications of these models, particularly for his own interest in protecting scientific integrity from regressive leftism. He considers various factors that might determine which model applies in a given situation, such as the initial level of taboo, the likeability of supporters, and the availability of alternatives for supporters. Shorter summary

Scott Alexander explores the potential link between falling testosterone levels and declining crime rates, finding the hypothesis intriguing but ultimately insufficient to explain observed crime trends. Longer summary

Scott Alexander explores the hypothesis that falling testosterone levels might be related to the secular decline in crime. He examines studies showing a significant drop in testosterone levels in American men from 1987 to 2004, and research linking higher testosterone to violent crime. However, he identifies several problems with this hypothesis, including timing discrepancies between testosterone decline and crime reduction, contradictory evidence, and the fact that crime is dropping in women at the same rate as in men. While intrigued by the potential connection, Scott concludes that the hypothesis doesn't fully explain the observed crime trends. He suggests further research, including studies comparing testosterone levels in violent criminals to the general population and proposing an examination of digit ratios in historical skeletal remains to track testosterone levels over time. Shorter summary