Adoption of population-level statistical methods did transform psychological science but for the better: Commentary on Lamiell (2018)

Lamiell presents a case that differential psychology (the study of individual differences) and experimental psychology should properly be classified as a form of demography (psychodemography) rather than psychology. He indicates that individual differences pertain to correlations in a population and maintains that mainstream psychology misinterprets such correlations as attributes of individuals. Lamiell also claims that because experimental psychology uses group designs, it too is demography, and he recommends that experimental psychology return to "genuinely appropriate" methods of deriving general laws from the study of individuals. We disagree with Lamiell's assessment and classifications, and we emphasize that group experiments have yielded considerable knowledge about the nature of information processing in individuals.