Is there a word to describe someone who laughs at dumb little things but not at the real jokes?

besides annoying? when watching a comedy this person will let out a short but loud and obnoxious laugh at something dumb like the actor making a somewhat weird face or a sappy moment but then when an actual joke is delivered they dont laugh at all or try to contain their laughter. this habit this person possesses is quite strange to me and and makes the person poor company to watch anything with.