The chapter 9 is talking about intelligence and IQ testing which is divided into 5 small topics. At first, the book gives us the definition and then talks about intelligence testing, external factors' and group influence on IQ and other dimensions. (Chapter 9 Page 316)
It struck me when I get to know that the simple word intelligence has so many different definitions and comprehensions according to different psychologists. The concept becomes more and more accurate and complete after the hypothesis and research raised by psychologists in different generations. When I saw the new words fluid intelligence and crystallized intelligence, I am so excited because they are quite new to me. Then, I realized that the friends around me who are easier to learn new knowledge and learn faster are better in fluid intelligence. On the contrary, the friends who can remember words and history dynasty quicker are good in crystalized intelligence. The distinction of two concepts helps me understand my friends and myself better.
The content attracts me the most is the way to calculate IQ. To be honest, I am really curious about my IQ and did some so-called authoritative tests before. But when I was doing the test, I felt something might be wrong although I always got high scores at end. Besides, I think there are a lot of knowledge and statistics in calculating IQ. According to the book, the way to calculate IQ for children and adult are different. Because once we are 16, our performance on IQ test items doesn't increase too much. (Page 327, 3rd paragraph) Besides, in order to compare our IQ to others, the system of IQ testing needs a set of dorms. That is what Terman contributed to us. As a matter of fact, nowadays, IQ testing has been misused which cause big damage to the society. They are used in business rather than helping schoolchildren who need special help. (Page 327)