Eye‑darkness as reaction‑time marker

Propose treating ocular pigmentation (graded eye darkness) as a measurable, cross‑species phenotypic variable that could correlate with sensorimotor reaction speed; the hypothesis can be tested with preregistered human psychophysics, controlled animal studies and replication of the cited Penn State lab work and the 5,620‑species comparative database. — If robust, the idea affects debates on biological contributors to performance (sports, occupations), reorients how scientists frame race‑adjacent claims (eye darkness vs race), and creates a high‑stakes need for replication and ethical governance because of misuse risk.