Yeah, that is only the beginning of the massive number of differences. Calvin in the books is willing to destroy dozens of robots on the suspicion that one of them could kill a human though a convoluted interpretation of it's modified first law. She's all about the dangers of fiddling with robots and the vagaries that arise when the laws are interpreted by the complex robot mind. The Calvin in the movie has faith in the laws and seems emotionally attached to the robots. Have changed the wording, etc.