Twins reared apart do not exist
3 days ago
- #genetic determinism
- #IQ heritability
- #twin studies
- The article critiques the scientific validity of twin studies, particularly those involving twins reared apart, arguing they are flawed due to biases like shared congenital factors, early life experiences, and non-random adoptive family placements.
- It highlights the case of the 'Jim Twins' to illustrate how coincidences in twin studies can be misinterpreted as genetic determinism, overlooking socio-cultural influences.
- The author disputes the heritability estimates of IQ, suggesting that even if genetic factors contribute, the range of 30-50% heritability leaves significant room for environmental influences and personal agency in cognitive development.
- The piece calls into question the reliability of studies by Cyril Burt and Thomas Bouchard, pointing out methodological issues and the lack of differential analysis between monozygotic and dizygotic twins reared apart.
- It concludes that the debate over IQ heritability is complex, with no definitive method to separate genetic from environmental effects, and emphasizes the importance of recognizing the interplay between both in shaping cognitive abilities.