The Flynn-effect is something very interesting.

From Wikipedia:

The Flynn effect is the substantial and long-sustained increase in both fluid and crystallized intelligence test scores measured in many parts of the world from roughly 1930 to the present day.

But does this increase means on tests mean that we are actually getting smarter (often described as “g”)? Flynn himself already has doubts, e.g. education more ad more mimicking IQ-tests could be also an explanation. Steven Johnson thinks it’s also because of the rising complexity of popular culture.

But maybe it’s also because… we are more inclined to guess. This is what new research by Woodley et al. suggests.

Highlights of the research:

• The true independence of the Flynn effect from g is masked by a Brand effect.
• The Brand effect results from increased guessing on harder test items.
• Controlling the Flynn effect for the Brand effect boosts its independence from g.

Abstract of the research:

The cause of the Flynn effect is one of the biggest puzzles in intelligence research. In this study we test the hypothesis that the effect may be even more independent from g than previously thought. This is due to the fact that secular gains in IQ result from at least two sources. First, an authentic Flynn effect that results from environmental improvements and should therefore be strongly negatively related to the g loading (and therefore the heritability) of IQ subtests. Second, a “Brand effect”, which results from an increase in the number of correct answers simply via enhanced guessing. As harder items should encourage more guessing, secular gains in IQ stemming from this Brand effect should be positively associated with subtest gloadings. Analysis of Estonian National Intelligence Test data collected between 1933 and 2006, which includes data on guessing, g loadings and secular IQ gains, corroborates this hypothesis. The correlation between gains via the Brand effect and g loadings is .95, as predicted. There is a modest negative association between raw secular gain magnitude and subtest g loadings (− .18) that increases to − .47 when these are controlled for the Brand effect. Applying five psychometric meta-analytic corrections to this estimate raises it to − .82 indicating that the authentic Flynn effect is substantially more independent from g than previously thought.