The researchers behind one of the Norwegian studies have made some very weird arguments in public statements that aren't part of their research.

They said that the drops in IQ are not explainable by immigration, but this is something that is only the case in their own study in Norway where the IQ drop was something like 1-1.2 points per decade, while the countries with big drops-- France and the UK have drops that are about 3.2-4.3 times higher.