As Crown Prince Zhong grew in age, his developmental disabilities became clear to his parents and the imperial officials alike. He learned how to write and speak, but appeared to be unable to make logical decisions on his own at all. Once, when he heard frogs croaking, he asked, in all seriousness, "Do they croak because they want to, or because the government ordered them to?" Several times, officials reminded Emperor Wu of this, but Emperor Wu, not realizing the extent of Crown Prince Zhong's disability, resisted the implicit calls for him to be replaced. Indeed, because Emperor Wu was concerned that many officials were impressed with his talented younger brother, Sima You the Prince of Qi and might want Prince You to replace him instead, he eventually had Prince You sent to his principality, and Prince You died in anger in 283.