A meta-analysis of a large number of studies using the d2 Test of Attention from the past three decades found evidence that selective attention scores on this test have been increasing in adults, but not in children, through generations. On the other hand, there was a substantial increase in overall errors and processing speed in children. The paper was published in Personality and Individual Differences.
In the 1980s, James Flynn, a social scientist from New Zealand, observed that intelligence test scores in the general population of the developed world had been rising throughout much of the 20th century. This rise was particularly significant in measures of fluid intelligence, which encompasses skills like problem-solving, pattern recognition, and abstract reasoning. This contrasts with crystallized intelligence, which relates to accumulated knowledge and skills.
The phenomenon, which came to be known as the Flynn effect, sparked various theories. Some theorists attributed the rise in human intelligence to enhanced nutrition, education, and childrearing practices. Others posited specific environmental factors, such as mercury poisoning, as the cause of this intelligence increase. Ultimately, Flynn himself concluded in a book that people had become more adept at solving tasks typical of intelligence tests, rather than experiencing an increase in intelligence per se. Interestingly, this upward trend in test performance seemed to plateau around 2010.
Study author Denise Andrzejewski and her colleagues wanted to explore whether the Flynn effect was present in results of a specific test of attention called d2 Test of Attention as well. Their research, covering the period from 1990 to 2021, examined generational shifts in processing speed and error rates.
To find studies that used the d2 Test of Attention, these researchers searched a number of databases of scientific journals for “d2” and “attention” and “d2 Test of Attention” in different languages. They looked for papers describing studies that reported mean scores and variability of test scores, and that investigated healthy participants.
The search resulted in a final group of 179 studies that met all their criteria. These studies together included 21,291 participants. The studies were predominantly from Germany (37%), Spain (14%), and the USA (7%), with the rest spread across 31 countries. The average age of participants was 26 years, and just over half were women.
Results showed that there was no overall change in selective attention scores in children. Mean scores obtained between 2003 and 2020 were similar. On the other hand, average selective attention scores of adults improved over time. Between 2000 and 2021, average scores tended to become higher and higher as years progressed. There were no changes in test effectiveness.
Further analysis showed a very slight trend of increase in processing speed in children in the studied period. When gross domestic product of a country and internet use were taken into account, this trend became even more visible. Children in later generations also tended to commit more errors on the test. But both of these trends were absent in adults.
“We show here first evidence for a Flynn effect for attention. This effect appears to be differentiated according to participant age, indicating moderate positive concentration performance changes for adults, but not for children. Conceivably, this may indicate a meaningful role of executive functions for changes in more traditional IQ [intelligence quotient] domains. Cross-temporally increasing error rates and processing speed of children may be attributed to more impulsive behaviors whilst taking tests,” the study authors concluded.
The study sheds light on changes in attention scores of the d2 Test of Attention across the last three decades. However, the d2 Test of Attention is just one test of attention and the study completely focused on it. Studies using a different test or a variety of tests might not produce equal results.
The paper, “Is there a Flynn effect for attention? Cross-temporal meta-analytical evidence for better test performance (1990–2021)”, was authored by Denise Andrzejewski, Elisabeth L. Zeilinger, and Jakob Pietschnig.
