Of course non-programmers aren't used to being extremely precise with their grammar to express solutions to logic problems. We have the capability of getting the "gist" of what someone is trying to express that machines current don't. Expressing those thoughts to a machine requires precise syntax and well formed flow control. I honestly don't find much in this paper that's very surprising, but I think the participants did pretty well given that they aren't expected to be extremely precise on a day-to-day basis.