IQ tests are assessments that measure a range of cognitive abilities and provide a score that is intended to serve as a measure of an individual’s intellectual abilities and potential. The reverse Flynn effect is a phenomenon that suggests a decline in IQ scores in some countries or regions over time, contrary to the previous trend of rising IQ scores known as the Flynn effect.
The study that you mentioned was published in 2023 by researchers from Northwestern University, who analyzed data from a large online personality and ability test taken by nearly 400,000 Americans between 2006 and 2018. They found that IQ scores decreased in three out of four cognitive domains (verbal reasoning, matrix reasoning, and letter and number series), but increased in one domain (3D rotation). They also found that the decline in IQ scores was not related to age, education, or gender. The study did not examine the causes of the reverse Flynn effect, but the authors suggested some possible factors, such as poor nutrition, worsening health, media exposures, and changes to education.
The reverse Flynn effect is a controversial and complex topic, and there are different opinions and explanations among scientists and experts. Some studies have reported a decline in IQ scores in other countries, such as Norway, Denmark, Australia, Britain, the Netherlands, Sweden, Finland, and German-speaking countries. However, other studies have found no evidence of a reverse Flynn effect, or a slower rate of increase in IQ scores, in developed countries. Some of the challenges and criticisms of IQ testing and the reverse Flynn effect are:
IQ tests may not be equally valid, reliable, or fair for different groups of people, such as those with different cultural backgrounds, languages, or disabilities.
IQ tests may not reflect the influence of other factors, such as motivation, personality, creativity, education, or environment, on a person’s performance or development.
IQ tests may not account for the multiple dimensions or types of intelligence, such as emotional, social, or practical intelligence, that are important for success in life.
IQ tests may not be stable or consistent over time, as a person’s IQ score may change due to aging, learning, or brain injury.
IQ scores may not capture the complexity and diversity of human intelligence, and they should not be used to label, limit, or define a person.
Therefore, IQ tests and the reverse Flynn effect should be interpreted with caution and critical thinking, and they should not be taken too seriously or literally. Intelligence is more than a number, and it can be developed and improved through various means, such as education, training, practice, and experience.