Yes............but we still have some people smart enough to point it out which is a relief, right?
Since the Second World War, the IQ of young people was observed to be steadily rising. Dubbed the Flynn effect — named after the work of New Zealand intelligence researcher James Flynn — it described a phenomenon in which humans’ intelligence quotient was rising at a rate of about three IQ points per decade in the 20th century.
However, that has been shown to have topped out around 1975 with IQ scores now falling. “Recent years have seen a slowdown or reversal of this trend in several countries,” researchers wrote in a new paper, published this week in the Proceedings of the National Academy of Sciences.
https://www.news.com.au/technology/science/human-body/the-reverse-of-the-flynn-effect-science-suggests-we-might-be-getting-dumber/news-story/ce3475a0817e65bd6e7710cca8b55074
Researchers from the Ragnar Frisch Centre for Economic Research in Norway studied the IQ scores of about 730,000 Norwegian men born between 1962 and 1991. They found that scores grew by nearly three percentage points every decade for people born between 1962 and 1975. But among those born after 1975, scores fell.
The cause of the IQ decline is due to environmental factors, and not genetics
http://time.com/5311672/iq-scores-decline-environment/
Here is the paper
http://www.pnas.org/content/early/2018/06/05/1718793115