We know that older people are:
(a) more likely to vote ("While 57% of 18 and 19 year-olds voted last week, for those aged 70+ the figure was 84%");
(b) more likely to vote Conservative ("amongst first time voters (those aged 18 and 19), Labour was forty seven percentage points ahead. Amongst those aged over 70, the Conservatives had a lead of fifty percentage points"); and
(c) more likely to have voted for Brexit ("Under-25s were more than twice as likely to vote Remain (71%) than Leave (29%).[...] while 60% of voters between the ages of 50 and 64 went for Leave").
Well, "The OECD found in a survey of 34 countries last year that the UK has one of the highest rates of literacy and numeracy in the 55-64 age group, but is in the bottom ten for 16 to 24-year-olds."
I know that correlation is not the same as causation, but I'm pretty confident that if there is a causal link it isn't because voting causes increased literacy or numeracy.
(The OECD finding was referred to in the LRB, but I somehow think they haven't drawn the same inferences from the data that I have.)