Hard to measure a complex reality as human intelligence with a number: the intelligence quotient or IQ is not everything, and according to some it is an old-fashioned value that does not describe many important personality traits. At the same time, however, it is an important parameter to predict and estimate longevity, health, and wealth, and the statistics relating to him we can draw some very interesting information. Most people have average intelligence. The IQ is a score that is achieved through standardized tests that measure short-term memory, reasoning ability, acquired knowledge, speed of information processing. The partial scores are added together and compared with those of the rest of the population. The average score, measured according to a Gaussian curve is 100. Only 2.5% of the population has an IQ equal to or greater than 130. A fascinating fact is that if you get a high score in one of the tests, you will tend to obtain in the other, although the topics seem very distant. Psychologists talk then of general intelligence factor (or g), which corresponds to the popular concept of intelligence. According to a study of one million Swedish men, people with lower IQs are at risk of death (from any cause) three times higher than those with the highest IQ.
The phenomenon can be explained in several ways: smarter people tend to earn more money and have more protective lifestyles (for example in terms of prevention and nutrition); people with a high IQ are also less likely to commit fatal mistakes: previous studies have shown, for example, there are lower risk of fatal automobile accidents. On the other hand, these same people are more prone to develop visual defects such as myopia, and to need glasses nerd. People with high IQ tend to be appreciated at work and to earn more money, but it is only a correlation and, as such, imperfect. For this reason it can happen to run into a lot of smart people working and badly. Moreover, the correlation between high IQ and happiness is generally positive, but not as statistically significant as to be guaranteed. The rich and successful people tend to raise the bar of personal satisfaction and to compare your achievements with others goals: therefore often tend to be unhappy. Finally, the IQ is not related to other important personality traits (such as being outgoing, pleasant or have emotional stability). The only one is related, is openness to new experiences.