Is This the Study That Rewrites IQ Theory?

"Now, new research from Horvath and Fabricant challenges that assumption, and it does so with the kind of study design psychologists dream of: examining identical twins reared apart. Their findings suggest that education, of all things, may hold surprising power to raise measured intelligence. For educators, this study could be a validation of an instinct we've tapped on for years. For the rest, it offers hope that misreadings of prior research had closed off."

"For as long as intelligence has been studied, we've been told that our raw IQ is mostly a genetic hand-me-down. Sure, we've learned how to sharpen the knives we were handed and increase our "effective IQ" through good habits, deliberate practice, and focus. But the raw numbers themselves, which we typically derive from Binet tests or Raven's Progressive Matrices, have been thought by many in the field to be all but carved in stone."

IQ shows high heritability but is not fixed; education can significantly change measured intelligence. Research using identical twins reared apart found that differences in schooling produced IQ gaps up to about 15 points. Classic twin studies reported correlations around 0.75, supporting strong genetic influence, but new findings indicate environmental factors like schooling still exert substantial effects. Neuroplasticity evidence indicates the adult brain can continue to grow and adapt when challenged, supporting the possibility of IQ gains later in life. Intelligence appears more dynamic and broadly accessible than previously assumed, elevating the role of schooling in shaping cognitive outcomes.

Read at Psychology Today