As if that were possible?
Seriously though, look waaaaaay back when he had his crush on Lisa. In that episode he was capable of conversation, even though this Lisa-fixation gave him a one-track mind. Ditta a few years later when Marge insisted that bart try to be friends with Ralph. We see a child, perhaps disturbed and immature for his age (well with the father figure figure he has, wouldn't you be too?). But both these episodes indicate a boy whose feelings are very capable of being hurt. ("I thougt we were friends!")
Now look at what he gets now. I admit I chuckled at the "Lisa Simpson is a girl at my school" scene. But he used to be more coherant than this. I know that it's partly because he misunderstood the question, but you'd think he'd be able to supply more than that one sentance about Lisa. At the least, shoudn't he have indicated, in some way typical of Ralph, that he once "dated" her?
On the other hand, here I am trying to psycholanalyse a cartoon character. Maybe I need therapy.
Brad