American IQ scores have rapidly dropped, proving the 'Reverse Flynn effect'

They say scores in spatial reasoning went up while analogies, vocabulary, and numerical reasoning declined.

Hmmm I wonder if an increase use of videogames paired with a decrease in the amount of time parents can spend communicating with their children might be related.

Note that over the last 30 years it's vastly transitioned from one parent staying home raising children to both parents working.

Humans are incredibly adaptive. Is there much reason to have an expansive vocabulary nowadays? We are taught to speak and write as concisely and understandably as possible. We can look up the definition of any word at our fingertips. "[I do not] carry such information in my mind since it is readily available in books." - Einstein.

Maybe these tests are declining because they are measuring skills that are decreasingly relevant? I'm not certain I believe this myself but it's an interesting thought.