Duck is deemed to be "dumber than a bag of hammers" and undisciplined, and he frequently displays symptoms of ADHD. He was nicknamed Duck because difficult things he went through (such as the apocalypse) went over "like water off a duck's back." On the surface, Duck can appear unintelligent, but he is smarter than others give him credit for. Such moments of intelligence occur when he helps Lee solve the mystery of the missing supplies. He has a wide knowledge of action comic books and usually obeys when others tell him to avoid trouble (aside from helping Lee's investigation whether Lee wants him to or not because he believed Lee was secretly asking him for help). Duck's lack of knowledge of the apocalypse is not stupidity as much as his parents protecting his young psyche. His accidental driving of a tractor onto Shawn Greene's leg and continuing to eat Mark's legs after the disgusting truth was discovered was simply due to childlike naivety (the latter more due to him not listening). Kenny later mentions that Duck keeps asking about Shawn, showing that Duck has remorse for his accidental role in Shawn's death.