The perception of Maisie, the child protagonist of What Maisie Knew, depends primarily upon her visual observation and her emotional feeling throughout the novel. As her experience increases, the capacity of her perception grows. Nonetheless, she does not seem to have a full-fledged linguistic and conceptual perception even at the end of the novel. This paper tries to analyze the perceptual process and limitations of Maisie in which she, while growing up, undergoes a change from the passive reception of visual stimuli to the active intellectual speculation. Meanwhile, she comes to understand the more about the convoluted relationships of the love affairs of her parents and step-parents, which are concealed under their hypocritical behavior and their use of rhetorical language. Although Maisie’s perception becomes more mature and comprehensive, still she cannot have a fully conceptual understanding of the moral and social implication inherent in the improper relationships of her parents and step-parents. It is so because having moral sense is a matter of conceptual understanding, but it is neither a matter of a sensory knowledge nor that of emotional comprehension.