Based on my admittedly limited understanding of the Flynn effect, the thing that's notable about this is not that American IQs are going down, because the same thing has been observed in Norwegian, UK, and Australian groups as well. The interesting thing about this is that until recently America was somewhat unusual in that measured IQs had NOT been going down or plateauing like they had in many other countries. The article makes no mention of the observed Flynn effect reversal, and would seem to imply that it is unique to America.

(I think all of this is really silly, and put very little credence in IQ tests as an instrument, or lean on the Flynn effect as anything but a sort of interesting metaphor for progress in the 20th century)