The Biggest Gains in g

It is one thing if a child’s IQ is elevated over time because she is drilled daily on vocabulary and basic number facts (two of the subtests of major IQ batteries). But Flynn and others have shown that these are not the areas where IQ has risen much. It is in what Flynn refers to as “on-the-spot reasoning” about relations between objects that are either totally familiar to everyone, hence no one can be claimed to have a prior advantage (e.g., arranging familiar pictures so they tell a coherent story) or objects that are totally unfamiliar to everyone (e.g., nonsense shapes that have to be seriated). On these types of tests the IQ gains have been enormous. If we gave our grandparents today’s tests they’d score near the mentally retarded range, something that neither Flynn nor most researchers believe reflects their intelligence, notwithstanding their low scores.

A relatively unexplored question is the causal pathways running from the early environments to later performance on g-loaded tests. Granted most of us do not directly teach our children how to arrange pictures to tell a story or how to seriate or cross-classify a multidimensional matrix of shapes, but perhaps there are activities that indirectly foster elevated scores on such tests. And perhaps these activities are more common with each subsequent generation, leading to the Flynn effect. There is some support for this view. For example research with Brazilian children demonstrates that every year of formal school attendance conveys an improvement in their Raven’s Matrices performance, the quintessential g measure. Raven’s Matrices are associated with the largest IQ gains in the 20th century, so there is clearly something that is associated with being in school that aids performance on the highly g-loaded IQ test.