Do your Siblings have a Higher IQ?


Birth order has always been an interesting concept that pertains to one's personality, success and many other attributes to a person. One of these attributes affected by a person's birth order was IQ. Robert Zajonc conducted studies that showed a correlation that later-born children had a lower intelligence than earlier born children. It was later realized that this correlation was interpreted incorrectly and the correlation was due too the fact that low IQ families tend to have larger families than high IQ families. This means children from larger families have lower IQs than chlildren that come from smaller families. This is an example of correlation vs. causation. The claim A was not caused by claim B, but by claim C.
Most studies of this subject show that there is little to no correlation between birth order and intelligence. I do believe there are things that are affected by birth order, like personality. I also believe that there is no correlation and that each individual is affected by things more important than birth order. Many people will probably hold the views that they have higher IQs than their siblings. Do you believe that there is a correlation between birth order and IQ? Here is an article for more information about the topic:


This is a very interesting topic especially for me since I have an older brother and two younger sisters. From my own family I can say I see no correlation between birth order and intelligence. My older brother and I have very similar test scores and I would assume we have very similar IQ scores as well. It is hard to tell with my younger sisters because of the age gap. Comparing my family to families I know that are similar sizes there is really no distinct birth order and intelligence correlation that I can find. Every family is unique and I would say if there are similarities it is just coincidental. On the other hand, I definitely have noticed distinct personality traits as it relates to birth order. I definitely believe birth order effects certain qualities, intelligence is just not one of them.

I found this post to be very interesting. I think birth order does play a role in some personality traits but I don’t think it affects IQ. I have an older brother and we’re basically the complete opposite of each other. I’m the one that tries the hardest in school in stuff but he’s the more easygoing one. I think he’s pretty smart but just not motivated. If he tries, he gets good grades but he’s fine with just getting by.

I also find this birth order and IQ debate to be very amusing. I am the youngest in the family, having just one older sister. In discussing intelligence, I would say we are actually pretty even. She had the higher ACT, I graduated high school with a higher GPA, and in other areas of comparison we are fairly similar. I feel as if the argument for saying that IQ decreases with birth order does not have substantial support, though our book and other sources say different. Even in many families I know, the difference in intelligence is not at all significant. I was looking at an article (listed below) that goes on to talk about other differences in birth order, one being that height and weight also decrease with birth order. I am taller and weigh more than my sister, so once again this argument is invalid for our family. While this relationship between my sister and I is just one example of millions, I do not believe these findings have enough support to be significant.

The following is an article that discusses numerous relationships between birth order and another variable (health, risk-taking, height, etc.).,9171,1673284-1,00.html

When I saw this topic in the entries' list, it was so interesting to me and I clicked this post. Because I'm a older sister who has a younger sister, I wanted to know more about the content. However, I don't think there is a relation between the birth order and IQ. Of course I agree that many things like such as personality or success can be affected by our birth order because the social request can be differ from it and they can affect us in forming our personality. However, I think IQ is somewhat different from the concept. In addition, IQ scores can be up to our effort. Therefore, I think IQ score and birth order doesn't have correlation or causation.

This topic interested me because their are five kids in my family including my self, I have an older brother, two younger brothers and a younger sister. What I have found growing up in such a large family is that there is not necessarily a difference in IQ, but there is a difference in the areas in which all of us siblings excel at, intellectually. We all are decently intelligent but in our own way, and I believe this may coincide with us having different personality types but there is definitely a difference in our strong intellectual areas. I believe that the differences we see can be attributed to personality because I believe that birth order definitely effects personality.

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This page contains a single entry by menn0073 published on April 8, 2012 11:13 PM.

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