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A reverse Flynn effect was found for composite IQ ability scores with large US adult sample 2006–122018 and 2011–72018.
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Domain scores of matrix reasoning, letter and number series, verbal reasoning showed evidence of declining scores.
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3-dimensional rotation scores generally increased 2011–72018.
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Differences in ability scores were present regardless of age, education, or gender.
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The steepest slopes occurred for ages 18–22 and lower levels of education.
[OSF] Compared to European countries, research is limited regarding if the Flynn effect, or its reversal, is a current phenomenon in the United States. Though recent research on the United States suggests that a Flynn effect could still be present, or partially present, among child and adolescent samples, few studies have explored differences of cognitive ability scores among US adults.
13 years of cross-sectional data from a subsample of adults (n = 394,378) were obtained from the Synthetic Aperture Personality Assessment Project (SAPA Project) to examine if cognitive ability scores changed within the United States 2006–122018. Responses to an overlapping set of 35 (collected 2006–122018) and 60 (collected 2011–72018) items from the open source multiple choice intelligence assessment International Cognitive Ability Resource (ICAR) were used to examine the trends in standardized average composite cognitive ability scores and domain scores of matrix reasoning, letter and number series, verbal reasoning, and 3-dimensional rotation.
Composite ability scores from 35 items and domain scores (matrix reasoning; letter and number series) showed a pattern consistent with a reversed Flynn effect 2006–122018 when stratified across age, education, or gender. Slopes for verbal reasoning scores, however, failed to meet or exceed an annual threshold of |0.02| SD. A reversed Flynn effect was also present 2011–72018 for composite ability scores from 60 items across age, education, and gender. Despite declining scores across age and demographics in other domains of cognitive ability, 3-dimensional rotation scores showed evidence of a Flynn effect with the largest slopes occurring across age stratified regressions.
[Keywords: Flynn effect, intelligence, cognitive ability, International Cognitive Ability Resource, Synthetic Aperture Personality Assessment Project]
Note: Data collection for the category “currently in graduate or professional school” did not start until August 2010. The dashed lines in the top graph connect the average standardized score and its associated standard error for each year and level of education.
The solid lines in the top graph represent the associated slope of the average standardized score for each level of education.
The lines in the bottom graph are the associated slope of the average standardized score for each level of education split between male (left) and female (right) participants.
‘ICAR’ = International Cognitive Ability Resource, ‘Grad/prof grad’ = Graduate or professional degree, ‘In grad/prof’ = Currently in graduate or professional school, ‘College grad’ = College graduate, ‘Some college’ = Some college, did not graduate, ‘In college’ = Currently attending college, ‘HS’ = High school graduate, ‘<12 years’ = <12 years of education.
…The present study aimed to examine if a Flynn effect or a reverse Flynn effect was a phenomenon within a large sample of adults from the United States 2006–122018. To our knowledge, this is one of the first studies of this size to examine differences in ability scores with an adult United States sample during the 21st century.
The results of the analyses completed with composite cognitive ability scores and domain scores had 5 primary findings: (1) There was no evidence of a Flynn effect across composite ability scores but possible evidence of a reversal; (2) one domain showed possible evidence for a Flynn effect, one domain showed no differences, and the remaining domains showed evidence of a reversal of varying magnitudes; (3) lower average scores were frequently observed for more recent participants across all levels of education; (4) differences in scores were similar across gender; (5) the greatest differences in annual scores were observed for 18–22-year-olds and individuals with less than a 4-year college degree.
…As the present study explored the differences in scores across levels of educational attainment and the highest level of education has increased across the testing period of the SAPA Project sample, our results suggest the causal hypothesis that exposure to education accounts for the direction and strength of the Flynn effect (2018; 2015) was not observed within this sample. Rather, exposure to education may only be protective for certain age groups. Not only did the present study find that the steepest negative slopes of composite or domain scores occurred for individuals with less than a 4-year college degree, the largest differences for age stratified regressions after controlling for educational attainment were exhibited for those between the ages of 18 and 22.
While these findings complement previous research with 18–20-year-old conscripts (2018; 2013; Sundet et al 200420ya; 2008) and a subsample of 18-year-old study participants within United States ( et al 2019), exposure to education has not been able to explain the differential gains and declines across fluid and crystallized IQ scores observed in previous research (2015). However, it could be the case that our results indicate a change of quality or content of education and test-taking skills within this large United States sample. As scores were lower for more recent participants across all levels of education, this might suggest that either the caliber of education has decreased across this study’s sample and/or that there has been a shift in the perceived value of certain cognitive skills ( et al 2016).