I can't see any mention of this in the post or on the page where it claims this is an indicator for intelligence.

now, since we're on the topic, we probably need to discuss whether or not this could be an indicator for intelligence.

I don't know how much research has gone into seeing whether or not there's a link between intelligence and working memory, but according to wikipedia [1], memory is one of the things that encompasses intelligence, so there might be a link.

1 http://en.wikipedia.org/wiki/Intelligence