When Bruno first finds out that Shmuel is Jewish, he says: “You’re a Jew. You can’t be. I think I should go now.” Why does Bruno react that way at first?

Bruno’s first reaction is probably so mixed because he is confused, and trying to piece things together in his head. He has been told that Jews are bad, but he does not know that the all the people at the concentration camp are Jews. When he has been told that Jews are bad, mean, greedy people, he doesn’t believe that Shmuel is a Jew because he is a perfectly nice little boy, which explains his “You can’t be.” He knows that he has been told he should never talk to Jews, so his first reaction to realising that Shmuel is a Jew is to leave.