People have always wondered why one person is as intelligent as they are. Scientists ask the question of whether or not it has to do with the brain size. This chapter is all about intelligence. Many interesting questions were asked in this chapter pertaining to how intelligence affects you as a person and studies show and prove different answers to these questions. One questioned asked was whether a person with higher intelligence has a faster reaction time or slower reaction time than a person with less intelligence. It was proven that a person with higher intelligence had a faster reaction time. Intelligence can be measured by the IQ tests that are proven to be valid. What I found most interesting was the section Genetic and Environmental Influences on IQ. It has been proven that IQ runs in a family. An interesting study was done to see if adoptive children have a similar IQ of their biological parents or their adoptive parents. Proven by research a adopted child is like their adoptive parents until the child reaches adolescence. An overview of this chapter from my point of view after reading the text would be that intelligence is affected by numerous aspects and has a very large impact on the way a person is going to turn out either for the better or the worse.