Was Raymond's daughter a psychopath (spoilers)?

"Let me know if I'm grasping at straws here. Raymond seems rather distant from his wife and older daughter. He shows affection towards them, but it seems almost like he was fulfilling a role to maintain his image of a family man. There didn't seem to be much warmth to me in his relationship with those two, especially in the scene where his wife asked if he was cheating, and he responded with a simple, curt, "no". This, to me, implied his lack of true feeling for his wife, because any other man would react with shock and incredulity to an accusation like that. "

many marriages are like that after a while.

"But he seemed especially close to his younger daughter. I wouldn't use this to draw the conclusion that she's a psychopath if not for one scene, relatively early on in the film. Raymond is picking her up from school, and she asks him, quite calmly, if he's taken a mistress. It seems to me that any normal child would ask this question (if they had the guts to ask it at all) with some amount of trepidation in their voices, rightfully expecting that their parent would be surprised or even angry at being asked a question like that by their child. And then, he does not answer her, only gives her a small smile which I took to mean that he wasn't ruling it out to her (a tacit confession, in essence). Her reaction is curious after this: she merely grins back, and when his wife is confronting him in the next scene and she walks in, she seems rather knowing. I thought I caught her smiling at her dad (this part might have been my imagination, and correct me if I'm wrong).

So does this explain his bond with her being closer than his bond with his wife and older daughter? They are able to connect only because they are both sociopaths who have no real sense of right and wrong? Let me know what you all think."

a) his self analysis as a sociopath is not accurate. he shows multiple different indications for different psychosii, but a straight up sociopath would behave differently.
b) she said that he had to right to have a mistress. i think we can take that at face value. i don't understand why people are looking for hidden side-aspects. the film is very straight forward in making clear what is important.

I also picked up on this. I think there are some other scenes that hints towards this as well.

In particular, the one that stuck out to me is when they are watching TV together, and the program about Rex is showing. Both the wife and oldest daughter are looking away, disinterested, but the youngest daughter is watching with Ray. The girl is then saying "That's us, daddy." Of course, you could say this is because they were present at the scene where Rex was "meeting" Ray, and they can literally see them selves on the screen. But note that when the camera shows the TV screen, we don't see this scene. Instead the program has cut to the interview with Rex.

To me, this symbolizes that Ray in some ways feels that his daughter is participating in Ray's game with Rex. He feels that "it's us" that's playing with Rex, not just himself. Whether this is because his daughter is a sociopath or not is open for interpretation, but it's at least apparent that Ray feels a strong connection to his daughter, and maybe sees some of his own sociopathic tendencies in her.

Also, in the birthday scene, the presents the daughters give Raymond are very different. The elder daughter gives him a knit sweater -- a nice gift certainly, but a bit boring and impersonal. The younger daughter had clearly put more thought into getting him more personal and meaningful presents: the key chain with his initial and the photo book.

all solid points in this thread. i agree with all of them

An interesting theory but I can't agree. The reason the film stresses Ray's strong relationship to his daughter is to set up his reason for murdering Saskia - as he explains to Rex, his daughter considered him a hero for saving the drowning girl, but he figures he can't truly be a hero unless he can also be a villain, so he cooks up the most villainous act he could imagine.

I think it frustrates Ray that his sociopathy prevents him from having normal relationships and healthy emotions. He felt no heroism in saving the girl, in fact he got more pleasure from watching her cry over him not saving her doll. In his twisted logic, he thinks that doing something wholly evil like horribly murdering an innocent girl, will allow him to feel heroism for saving one. It fails, at the end of the film he still feels nothing.

That said, a sequel entitled The Vanishings in which his daughter buries loads of people would be quite fun. She could even bury her whole family, including her dad, and eventually bury herself. Soon, the whole Lemond family are inside golden eggs, pursuing Rex and Saskia through dead space.