Scientists find clue to human brain evolution in finger length: Study
Summary
New research reveals that higher prenatal estrogen exposure, indicated by finger length ratios, is linked to larger head size in newborn boys, suggesting a role in human brain evolution.
Key Points
- Higher prenatal estrogen exposure, indicated by longer index fingers relative to ring fingers, is linked to larger head circumference in newborn boys.
- The 2D:4D digit ratio reflects prenatal hormonal balance and is associated with brain size and evolutionary traits.
- This estrogen-linked brain size increase in males may correlate with reductions in male viability, such as increased heart problems and infertility.
- The study supports the estrogenized ape hypothesis, indicating prenatal estrogen's positive role in human brain evolution despite biological costs.
