An important concept that I found to be the most interesting was among the twin studies. In the lilienfeld text Twin Studies is to compare correlations in a trait in two types of twins: identical and fraternal. It is found that identical twin studies are much more interesting because they share two times more the genetic makeup than fraternal twins. This comes in handy when measuring intelligence because it can be known as to whether or not it is passed down through your genetics.
I found this interesting because I can apply this to my own life. I have two older brothers. We all have a considerable amount of time between our births. I have always wondered which one of us has the higher IQ and which parent passed their intelligence onto us. A major factor that I was always aware of was that each of my brothers grew up in different social environments. Does growing up in different times and having different friend groups alter IQ? I have concluded that it is nearly impossible to make this information all be known, but I did find that intelligence heavily relies on genetics. Through the testing of twin studies. in the future it could all be known!
The link below contains an article about twin studies. I found a very interesting aspect of this article. It claims that identical twins raised apart were very similar to identical twins raised together. Furthermore concluding that the social environment does not greatly influence IQ.