There is a columnist in Parade magazine, Marilyn Vos Savant who writes about intellectual matters, mostly lightweight things like puzzles. However, she had a paragraph recently about common sense. She said that research shows that we learn to think early in life, mostly from our families. Some families instill logic and common sense, and some don't.

She didn't give references for the research, but I think she is right. Occasionally I have dealt with people who just don't make sense, and I assumed they had a hidden agenda or were lying. Most likely, they just never learned to think clearly.

Example: the driller who told my husband that he never puts his little boy in a car seat because "He just wouldn't stand for it." Hello?