by According to a phenomenon known over the last century as the “Flynn Effect,” human IQ scores have been rising by between 3 and 5 points per decade. But in a large sample in the US over the period 2006-2018, there was evidence of a reverse “Flynn effect” in all but one category, according to a study published in Intelligence. The study found that scores for verbal reasoning (logic, vocabulary), matrix reasoning (visual problem solving, analogies), and letter and number sequences (computing/mathematics) declined over the study period, but scores for 3D rotation (spatial reasoning) decreased from 2011 to 2011. – Generally up in 2018. Composite ability scores (a single score derived from multiple pieces of information) were also lower in the most recent sample. The differences in scores were independent of age, education and gender. The study did not investigate the cause of the decline, and the scientific community has no shortage of theories, including malnutrition, deteriorating health, media exposure and educational changes. The researchers say more research is needed.
