Apparently it is not a natural ability to "think" and reason. Or, my own theory, is that we have "taught" thinking out of students by stressing "knowing" for our all-important tests and students believe there is no need to think because there is only one right answer, "so just give it to me."
So, part of my mission as a teacher is to "teach" students to think again by NOT giving answers to questions they can answer for themselves. I prefer to ask them questions that help lead them to THEM finding the answer for themselves. My expectations are HIGH, but my students can achieve them...especially if they "learn" to THINK.