The IQ paradox is still resolved: Reply to Loehlin (2002) and Rowe and Rodgers (2002).

2002/10/01 by William T. Dickens, James R. Flynn · 5 citations
Psychology · Social Sciences · #Cognitive Abilities and Testing #Early Childhood Education and Development

paper · doi:10.1037/0033-295x.109.4.764

openalex publication_date 2002/10/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/01

Abstract

In their original article (W. T. Dickens & J. R. Flynn, 2001), the authors formalized the consensus model of reciprocal effects between IQ and environment and showed that it can resolve the apparent paradox between high heritability and large environmental effects. Commentators suggested that the model has undesirable properties that call its usefulness into question. J. L. Loehlin (2002) argued that incorporating persistence of IQ into the model causes problematic behavior. D. C. Rowe and J. L. Rodgers (2002) argued that an increasing correlation of IQ and environment should have caused growing variance of IQ. Empirical evidence suggests that IQ is not sufficiently persistent to cause the problems Loehlin found and that the correlation of IQ and environment has not grown much over time so that the reciprocal effects model need not imply increasing variance.

Citations

• Genetic and Environmental Influences on Vocabulary IQ: Parental Education Level as Moderator
• Heritability estimates versus large environmental effects: The IQ paradox resolved.

Cited by

• Intelligence: New findings and theoretical developments.
• Race, IQ, and the search for statistical signals associated with so-called “X”-factors: environments, racism, and the “hereditarian hypothesis”
• Thirty years of research on race differences in cognitive ability.
• Flynn effect [wikipedia]
• Intelligence quotient [wikipedia]