Had the results of this study shown that Intelligence Quotients had risen over the same period, I have no doubt that our educators would have claimed the credit. Indeed they did claim the credit for the previous steady rise in IQ scores. However, they seem to think this reported fall is nothing to do with them. It is all down to bad parenting and video games, apparently. I doubt Britain has a monopoly on those.
Perhaps neither explanation is right? It seems reasonable to theorise that IQ could be influenced by the regular exercise of independent thought. After all, if you fail to exercise any attribute, it will atrophy.
The nanny state; the concomitant move from education to propaganda; the switch from free expression to stock "right on" words and phrases and the indoctrination of all but the most unsophisticated to avoid "bad" words that reveal "inappropriate" attitudes have all arisen in the same period that IQs have fallen. We must beware of the post hoc ergo propter hoc fallacy of course, but could it be the infantilisation of the British population has caused this interesting effect? If all wisdom is received and beyond challenge, where is the need for analysis? In such an environment, is it so surprising IQs should fall?
Sadly, if true, the effect might well be self-perpetuating.