On my psychiatry rotation in med school, we would ask patients the following question during the initial interview: "How are a bicycle and an airplane alike?" The overwhelming majority of the psychiatric patients would answer, "Uh...they both got wheels!" It was depressing how few people replied with a more abstract answer. ("They are both modes of transportation.")
On a whim I asked the question to an acquaintance who is mildly mentally retarded and also has Tourette's Syndrome. He immediately replied with gusto, "Both!" and elaborated no further.
My friend's four year old daughter was coming home with her mother and they saw that the pickup truck of a friend of her dad's was in the driveway. "It looks like Mike is here," her mom said. "Yes," the girl replied, "his car is in the driveway." "Well...it's a truck isn't it?" her mother gently corrected her. The girl sighed and replied in a slightly irritated voice, "Well, it is a vehicle."
