Reading focus
Syllabus: What Is Intelligence?
Revisit the convergence across three batteries, using the corrected figure labels in the general guide. Now ask which causal theories could accommodate that convergence.
Why you’re reading it. Separate strong evidence about measurement structure from the stronger claim that one underlying process produced it.
A question to consider. A second battery yields nearly the same modeled general factor in the programme's learners. Why would this strengthen the measurement claim without deciding between a common cause and interacting abilities?
Why this reading
If a general factor has a meaning beyond one particular collection of tasks, comparable factors should emerge from different batteries given to the same people. This study turns that expectation into a concrete comparison while retaining broad and specific abilities beneath the general factor.
Before you read
A latent-factor correlation is estimated within a model; it is not the correlation between every pair of raw test scores. First-order factors describe groups of tests, and a higher-order factor represents what those factors share. Figure correction: two WAIS factor labels were reversed. The published corrigendum places Arithmetic, Digit Span, and Picture Completion under Freedom from Distraction, and Block Design, Picture Arrangement, and Object Assembly under Perceptual Organization.
Read for
- Ask how independently developed batteries test a stronger claim than extracting a factor in several ways from the same tests.
- Follow the sample, missing-data decisions, and model specifications behind the estimated correlations.
- Keep the general-factor result separate from the meaning and reliability of the more specific abilities, which the authors explicitly retain.
Consider afterwards
- Near-perfect modeled general-factor correlations occur alongside imperfect agreement between individual test scores. Why is that possible, and what would be needed before treating two tests as interchangeable for an individual?
Editorial context
The sample comes from a twin-study programme and associated family members; it is not a population census. The analysis includes related participants and assumptions about missing data and factor structure. Convergence across these batteries does not identify a unique biological mechanism or validate every use of an intelligence score. The 2004 correction concerns the reversed figure labels, rather than reporting revised general-factor correlations. Interpret the diagram with those labels corrected.