“1.10 Four Kinds of Predictive Validity for Intelligence Tests
1.10.3. Everyday Life
The importance of general intelligence in everyday life often is not obvious but it is profound. As Professor Earl Hunt has pointed out, if you are a college-educated person, it is highly likely that most of your friends and acquaintances are as well. When is the last time you invited someone to your home for dinner that was not college-educated? Professor Hunt calls this cognitive segregation and it is powerful in fostering the erroneous belief that everyone has a similar capacity or potential for reasoning about daily problems and issues. Most people with high g cannot easily imagine what daily life is like for a person with low g.
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Consider some statistics comparing low and high IQ groups (low = 75–90; high = 110–125) on relative risk of several life events. For example, the odds of being a high school dropout are 133 times more likely if you’re in the low group. People in the low group are 10 times more at risk for being a chronic welfare recipient. The risk is 7.5 times greater in the low group for incarceration, and 6.2 times more for living in poverty. Unemployment and even divorce are a bit more likely in the low group. IQ even predicts traffic accidents. In the high IQ group, the death rate from traffic accidents is about 51 per 10,000 drivers, but in the low IQ group, this almost triples to about 147. This may be telling us that people with lower IQ, on average, have a poorer ability to assess risk and may take more chances when driving or performing other activities (Gottfredson, 2002; 2003b).”