Testosterone Tolerance and the Origins of Economic Specialization: A Two-Phase Hypothesis

Superseded early working hypothesis; retained as a record of project development. The author no longer endorses the evidentiary claims, numerical thresholds, or quantitative inferences in this version. The text below is preserved for archival purposes and should not be treated as representing the author’s current research position. This two-phase, Class C hypothesis integrates testosterone physiology, encephalization (EQ), and economic organization across advanced tool-using taxa. Phase 1—shared by archaic Homo and peak tool innovators (crows EQ ~4.1 clade-relative, capuchins ~4.8, dolphins ~4.1–5.3, Neanderthals ~4.0–4.8)—shows high-T parochial altruism maintaining generalist economies above EQ ~3.0 (clade-relative). Phase 2—Homo sapiens only (~80–50 kya)—involves T-reduction via craniofacial gracilization, enabling universal tolerance for group-level economic specialization beyond generalist ceilings (~115–150 individuals). Primary prediction: Post-50 kya sapiens show greater upper-limb enthesophyte variance than Neanderthals (Levene's p