Iq and Twins

Over time, much debate has been put into understanding why some people are intelligent and some are not. The common question asks whether genetics or environment play a larger role than the other. Identical twins help us better understand this issue because they are the only people in the world that share the exact same genes and this is a result of a single fertilized egg that was split into two. Due to this exact genetic makeup that identical twins share, any difference among them can be claimed due to environmental factors rather than from hereditary makeup.

In a test done comparing identical twins that were raised together they had very similar IQ scores. The same test was done for fraternal twins that were raised together and their IQ scores were less similar. Fraternal twins differ from identical in the way that they developed from two distinct fertilized eggs rather than a single fertilized egg split in two. These comparisons help researchers better understand that genetics definitely play a role in a persons intelligence.

Even so, when identical twins that were not raised in the same home were tested their IQ scores did vary slightly indicating that environment does play a role in a person’s intellectual abilities. Overall, the results of the IQ tests given displayed that the more closely two individuals are related genetically, the more similar IQ scores are. Identical twins help display that there is not just one factor that influences intelligence but both environment and genetics. Some people are more inclined to have higher intelligence but if not brought up in the proper setting or environment, they may not be able to live up to their full potential, and vise versa.

Hockenbury, Don H., Hockenbury, Sandra E. (2007). Discovering Psychology: Fourth Edition. New York: Worth Publishers.