Many researchers in the field of psychology have conducted experiments and observations of twins in a twin study. Twin studies compare the correlations in a trait in two types of twins: identical (monozygotic) and fraternal (dizygotic). Higher identical than fraternal twin correlations strongly suggest genetic influence. In fact, almost in most cases, studies of twins reared together have offered evidence of considerably higher identical than fraternal twin correlations for IQ. I think that this evidence is interesting, and also true. I had two sets of twins in my grade in high school. The identical pair seemed to have their intelligence and many other traits positively correlate. The fraternal ones seemed like they were very opposite than the identical pair's case. This is just supporting the fact that the traits in identical twins are more positively correlated than what fraternal twin's might be. However, I know a pair of identical twins that are completely different in every way. Obviously there are outliers in most sets of data, but this is showing the replicability of the research findings in the textbook.
Twin Studies
I found this part of the reading very interesting. I always thought that traits and intelligence were traced back to environmental factors. I remember in the text how the monozygotic twins that were reared apart almost always had a positive correlation between traits. I wonder why there are some outliers though. Also this made me think that some people are either destined for greatness of failure.
I have noticed this too. Some monozygotic twins look the same, act the same, and basically do everything the same. Others almost try to beat the system and refuse to conform to the somewhat stereotypical twins. They do this by expressing what they are interested in or even just do the complete opposite of what the other twin does.
I have noticed that identical twins tend to be very similar and more closely correlated than fraternal twins are. Two of my friends that i grew up with were identical twins and they have the same interests and do everything the same as each other. They both even decided to go to the same college. On the other hand i know another set of twins who were fraternal twins and they have completely opposite interests. I find this very interesting,
There were many sets of twins in my high school, I noticed many of the same things you did. Some identical twins were very similar, while other identical twins were completely opposite. And the same thing with fraternal twins. Some were into the same things and others wanted nothing to do with what the other twin was into. I think it makes sense that identical twins are more highly correlated, but I don't always see this as the case.
At my high school, there were six sets of twins and I noticed that the identical twins had similar interests while the fraternal twins were totally different. The identical twins were in the same activities and they took the same rigorous classes, while the fraternal twins dressed differently and even varied in intelligence. However, there are some sets of twins that prove the causation versus correlation between twins wrong.
I am an identical twin and me and my twin are similar in many ways but different in others. We usually come around to trying whatever the other twin finds interesting or enjoyable and we often like the same things but the extent to which we enjoy doing any particular activity is often different. For example, we both like chess, jarod (my twin) enjoys the game but i often spend hours watching and trying to learn from the games of grandmasters which is something he has never felt the drive to do.
I have a close friend who is an identical twin. Both of them are very intelligent but are interested in completely different things. It it interesting that their overall level of intelligence is so similar but that they can still differ in other attributes.
What do you think accounts for the difference in the two sets of twins you describe?