The one similarity among all of the floods, he notes, is that there was plenty of moisture flowing up from the Gulf of Mexico, which fuels the storms that caused the floods.
The sheer compulsion of reliable and almost immediate reward is being linked to similar chemical systems in the brain that may also play a part in drug addiction.
Though the world in which humanity evolved was nowhere near as polygamous as Moulay Ismail's, neither did it resemble the modern one of monogamous marriage, which distributes women widely.
Children might have headaches, dizziness or fatigue, which are usually blamed on things like eyestrain or lack of sleep, but could be signs of hypertension.