Full disclosure: I have long hair. I like long hair. But I think that anyone who believes the North Korean television claims that (according to the BBC) "stressed the 'negative effects' of long hair on 'human intelligence development', noting that long hair 'consumes a great deal of nutrition' and could thus rob the brain of energy" has completely unrelated intelligence issues already (or at least a severe education problem, which may not be unlikely in North Korea). This is part of a more general campaign to make sure that all men (they don't seem to care about the intellectual development of their women) get a haircut at least once every two weeks in one of several state-sanctioned styles.
This may fall into the category of the big lie technique — it's the kind of claim one would never expect a reasonable authority figure to make without some serious support, but some quick searching around the net finds absolutely nothing about such a relationship.
I have to wonder how much this campaign was driven by barbers trying to increase their revenues, and I find some amusement in a comment by someone widely held to be quite intelligent touching on hair and frugal behaviour:
Long hair minimizes the need for barbers; socks can be done without; one leather jacket solves the coat problem for many years; suspenders are superfluous.
(Admittedly, I'd miss my socks if they were gone.)
