Adults’ ability to concentrate has increased over the past 20 to 30 years, according to a meta-analysis in the journal Personality and Individual Differences. The research group that conducted the study, led by Denise Andrzejewski of the University of Vienna, sees this observation as initial evidence that attention is also subject to the Flynn effect, a phenomenon that was observed in many countries in the mid- to late 20th century, in which the population’s mean IQ, or intelligence quotient—as measured through standardized testing—rose from generation to generation.
The effect is named after the late political scientist James Flynn, who first reported on it in 1984. On average, IQ scores rose by around three points per decade, but this trend is now stagnating in some countries and has even reversed in others. Experts do not agree on the causes of the decrease in IQ.
The ability to focus attention is a component of general intelligence and may contribute to the Flynn effect. With this idea in mind, Andrzejewski’s team analyzed data from 179 studies involving a total of more than 21,000 people from 32 countries, including the U.S., Germany, Austria and Switzerland. Between 1990 and 2021 all of the participants had completed the d2 Test of Attention, a standard psychological test that measures the ability of selective and sustained attention—in other words, concentration.
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The test consists of 12 to 14 lines of the lowercase letters d and p, depending on the version. Each line has 47 letters, and there are one, two, three or four small vertical markings above or below each letter. The test taker must cross out each letter d that has two markings as accurately as possible but also as quickly as possible because the time is limited to an average of 20 seconds per line.
On average, concentration performance (defined as the number of correct answers minus incorrect ones) increased moderately in adults between 1990 and 2021. For children, however, it remained roughly the same. Although children worked increasingly faster throughout the years, they made more mistakes. The researchers interpret this as an indication of impulsive testing behavior that is possibly caused by a greater societal tolerance for errors and an increased tendency to measure performance in terms of speed rather than accuracy.
The results were slightly different when the group looked at German-speaking countries separately. Children in these countries did not make more mistakes but fewer, and the adults’ ability to concentrate did not increase. The overall conclusion across the more than 30 countries studied was that the Flynn effect also applies to our ability to concentrate. And this increase could contribute to an increase in intelligence, bolstering the actual Flynn effect.
This article originally appeared inSpektrum der Wissenschaftand was reproduced with permission.
