My theory is the vast majority of people are capable of much higher level thinking than they are currently doing. For one, many people are concerned about affections, more than intellect. Additionally, those people are having most of the children unfortunately. Intelligent people have less kids, is a fact I have heard, maybe I am wrong? Then there are the people who may have done poorly in school who think they are unintelligent because they have been put through an education system which presents itself more as a means to "weed people out," than to encourage learning beyond "hard," memorization. Typically, we also live in a society that values "appearance," more than logic or reasoning. Which is something I heard in speech class. Fairly certain it is true, thus money and wealth will directly lead you to more regard than actual intelligence. Moreover, we have become more and more programmed that these are indicators of success via dress codes, uniforms, television, etc.