The sentence above was given as an example sentence for one of my LiveMocha lessons. (The direct translation is: The baby doesn't want to eat anymore food).

I am confused by the use of the differential ending here (ie the use of '습니다'). It is my understanding that this ending is used to honor the subject of the sentence (ex. 서냉님깨서 키가 크습니다, the teacher is tall). However, in this sentence, the subject "baby" cannot possibly be honored.

My apologies for asking a question about sticky honorifics, but I am really interested in understanding the Korean language within the context of its confucian culture, so getting a grasp on this early is important to me.

The usage of this formality actually depends on who you're talking *to*, not who you're talking *about*. Honorifics in Korean can take time to figure out, but as long as you are attentive you will eventually figure it all out. (FYI - "큽니다" is the correct form of the verb here: 하다 -> 합니다 -- 크다 -> 큽니다 -- 없다 -> 없습니다)

도움이 감사합니다, 아리크스