Throughout the 20th century, the intelligence quotient (IQ) of individuals in many industrialized nations around the world experienced a substantial increase. A growing number of studies carried out in various countries in recent years have supported this trend. Recognized as the Flynn Effect, this phenomenon is named after the New Zealand political scientist James Flynn, who initially identified it in the United States in 1984.
Weakening Flynn Effect
The curve seems to have flattened somewhat by now. Around the turn of the millennium, the average IQ increase appeared to stagnate in some examined countries, with some even experiencing a slight decline in average intelligence scores.
As for what has caused both the rise in average intelligence and the declining trend, speculation is currently the only recourse. However, experts have found many indications that genetics does not play a role, but rather environmental factors such as changes in education and nutrition are responsible.
21,000 People From 32 Countries
The concentration ability of adults has consistently declined over the past 20 to 30 years, according to a meta-study conducted by a team led by Denise Andrzejewski from the University of Vienna. As reported in the journal Personality and Individual Differences, this finding is a significant indication that attention is also subject to the Flynn effect.
The study is based on data from 179 studies involving over 21,000 individuals from 32 countries, including the USA, Germany, Austria, and Switzerland. All participants underwent the d2 test between 1990 and 2021. This standardized psychological test assesses the capacity for selective and sustained attention.
The d2 Test
In this method for assessing concentration, participants are required to pick out the lowercase letters d and p within 47-character lines, marked with specific indicators, within a predetermined timeframe. A comparison of the results from these tests over the past decades clearly indicates an improvement in concentration performance during the study period.
Interestingly, this enhancement is observed exclusively in adults. Conversely, no corresponding development was noted in children. While children became progressively faster at solving the task over the years, they also exhibited an increase in errors.
German-Speaking Countries Are Different
Andrzejewski and his colleagues have hypotheses about the possible reasons for this: There may be a growing tendency to measure performance more in terms of speed than accuracy. Impulsive testing behavior, stemming from a broader societal tolerance for errors, could also play a role, according to the researchers.
Furthermore, it is noteworthy that the results in German-speaking countries differed from those in other regions. In those countries, children did not make more errors over the course of the study period; instead, they made fewer. However, the concentration ability of adults did not increase significantly. Overall, the team is convinced that the increase in attention contributes to the rise in intelligence and reinforces the underlying Flynn effect.