Scott proposes a 'low-hanging fruit' model to explain trends in scientific discovery, using a foraging analogy to illustrate why early scientists make more discoveries and at a younger age.
Longer summary
Scott Alexander proposes a model to explain several trends in scientific discovery over time, using an analogy of foragers in a camp. The model suggests that early scientists make more discoveries than later ones, amateurs are more likely to contribute early on, and the age of discovery increases over time. These trends are less pronounced for brilliant scientists and don't apply to new fields. The model provides a mechanical explanation for trends often attributed to political factors, though Scott estimates it accounts for about 75% of the effect.
Shorter summary