The Scottish folks who lived longer in reference to a higher IQ is not surprising. It boils down to lifestyle. If you are dim, you'll have a job that most likely requires heavy labor, long hours and little rest. The reduction of salary leads to poor nutrition and a movement towards addictive substances like alcohol and tobacco to ease the pain of existence. People who have a Master's degree or higher stay married longer and divorce less, which preserves familial well being and a more solid economical standing. Basically, if you have a high IQ your going to make better choices, have more leisure time and access to vacations.<br>Personally, I believe the uptick in IQ is directly related to improved food availability and quality.  We already know that malnutrition is directly related to mental weakness.