What developmental science identifies as the highest-leverage variables for children ages 4-6. Reveals the shocking Duncan study finding that early math skills—not social-emotional competence—are the strongest predictor of later academic success, examines how executive function acts as a cognitive amplifier across 25 lifespan outcomes, and exposes the implementation paradox where Tools of the Mind produced effect sizes ranging from 0.0 to 0.8 based purely on teacher fidelity. Full research report: https://research.yuda.me/podcast/episodes/kindergarten-first-principles/ep1-developmental-imperative/report.md
