Lane seems to be the epitome of the college-age intellectual that Franny detests. He rambles on and on about a paper he got an "A" on and name-drops the famous professors at his University. He knocks Flaubert as a "goddam word-squeezer" (Franny.2.15). He's only with Franny, from what we can tell, because she's the right kind of girl to be seen with in public. Lane doesn't understand the enormity and weight of Franny's spiritual crisis – while she's revealing how important the religious book is to her, he's talking to his frog's legs and worried about making the game on time.
Lane's character, it's interesting to note, is really the only outsider in Franny and Zooey – that is, he's the only non-Glass character we get to see. Salinger sets up the Glass family as a very insular, oddball, particular group. They all (at least the siblings we hear about in depth) have unusually strong spiritual interests, oppose materialism, and struggle to maintain a normal, sociable exterior. Lane proves how difficult it is for these Glasses to interact with anyone outside of their family. Franny's interaction with Lane in the first half of the novel is almost a foil to her conversations with Zooey in the second. Franny's conversation with Lane is a deluge of misunderstanding and miscommunication, while the conversation with Zooey is as close as we get to pure and perfect communication.