Is Intelligence Inherited?

2007/12/12
By Student
smart

Photo by INoxKrow

by Lauren K

Next time you’re about to get a lecture about your grades, try blaming it on your genes! An old study of inherited intelligence of fraternal and identical twins has brought to light how much of your intelligence is due to genetics and the environment.

Surprisingly, the study of inherited intelligence isn’t as recent as you may have thought. According to a recent study directed by Dr. Bouchard at the University of Minnesota, evidence supports that nearly 70 percent of your intelligence is inherited! Studies beforehand only suggested fifty percent, but this twin study pointed towards inheritance being, “the overwhelming contributor to intelligence test scores.”

Now, only six years ago and using more up- to- date technology, Dr. Bouchard conducted a lengthy study also using both kinds of twins with an MRI to distinguish areas of the brain. These were their results.

In the area of the brain that specializes in language, and another area mostly for perception, identical twins appeared to have ninety-five to a hundred percent shared. The cognitive area of the brain seemed to display the closest percentages. Dr. Thompson believes that the findings show that environment has little to do with intelligence. In fraternal twins, the percentage was lower, but still supplied evidence that intelligence was related to inheritance. So far, a single gene has not been found to specifically code for intelligence, but the evidence does show that inheritance is a factor.

Be sure to know that with many items in science, there are contradicting hypotheses and many doctors agree, disagree, and go back and forth on a decision. So in short, while there is prominent evidence that intelligence is inherited, there are some doctors who disagree, and others who say it’s a mixture of inheritance and environment.

24 Responses to “Is Intelligence Inherited?”

  1. Miss Baker Says:I really like that you brought this discussion to the blog, Lauren. Many students already buy into this concept that intelligence is predetermined (and like to use it as an excuse for not doing well – “I’m just no good at INSERT SUBJECT HERE”).I’m not convinced at all. In fact, in a future post I’ll provide a counterpoint to Dr. Bouchard’s claims. Also, just want to point out that IQ (what was measured in the study) does not necessarily correspond with success in school or in adult life.But, if intelligence is largely inherited, wouldn’t it be a polygenic trait rather than controlled by a single gene due to the multiple ranges in intelligence seen?
  2. Roger Says:

    Wow that is really interesting. I agree and disagree on this topic. I do believe that some intelligence is inherited, while another part of it is just your ability to focus in school. If you have good grades, it doesn’t mean your parents are geniuses. You have to work at school, you can’t just expect to do well because your parents did.

  3. Roger Says:

    I was just talking to my older sister and she said when she was in college they did a study on this. They ended up saying that it was your parents intellegence on when to have a child that affects your rate of intellegence. So if you were born while your parents didn’t have a stable finacial plan to support a child you would have a worse intellegnce rate. This sounds really weird and dosent sound to accurate though.

  4. Jon G. Says:

    Wait, I have a question for Roger: Are you saying that your parents intellegence on when you are born effects your intelligence or are you saying that your parents intellegence on HAVING you effects your intellegence?

  5. michael Says:

    Wow this is really suprising to me. I had heard to really pretty people make an ugly baby so I thought two really smart people make a not so smart baby. But it makes since that intellegence is inherited just many physical characteristics.

  6. Steven T Says:

    i do think that your “ability” to be smart is inherited but i think i bigger part is based on the persons personality and liefstyle. Some people may enjoy school, though i dont think i know anyone who does….anyway, i think the main factor in someones grades are how much they put into their schoolwork.

  7. Matt Says:

    This is very interesting. Good job Lauren! i agree that some intelligence is inherited but some is just the want to apply it. You could be the smartest person, but if you don not apply yourself and are just lazy you will never come across as intelligent. Some people can also be born with neurological disabilities, that does not mean their parents were stupid or had these same problems. I know of people that have learnig disabliites and neurological issues and their parents and sibilings do not. It is also possible for peole with not very smart parents to be absolute genuises. What really is intelligence defined by? Is it something actually instilled into your DNA or is it just the willingness and want to be smart?

    Also, I heard( and this could be totally wrong) that IQ is just the measure of your brains capacity to store knowledge and information, is this true?

  8. Charlotte Says:

    This is really cool! I have never herd of intelligence being inherited. That would make it really cool if you had really smart parents. Even though a person might be handed down intelligence they still need to work for it because with out using your ability and trying to make it better you are just wasting the ability God has given you. I don’t really believe someone can be naturally smart enough to go through school with high A’s and not study or review for anything., but if there is someone please let me met them.

  9. stephen d Says:

    This is an interesting topic and if intelligance is inherited than that will be really cool. Does this happen in every family or is it in some or in just most families? I have seen some families that have very smart parents and very smart kids so i was wandering about this.

  10. Stevie Says:

    Very nice Lauren! That’s really fascinating beacuse I always just took it for granted and thought that it was almost polygenetically inherited from someones parents. It never really ocured to me that envirornment also very well could play a large factor in it. In my family, I’m the first born child and I’m very like my dad in terms of phenotype, but I usually make grades closer to those that my mom used too make, but not quite as high. But my sister has a phenotype much more like that of my mom and she makes better grades than either me, my mom, or my dad. So it would make sense that our phenotypes expressed similar behaviors in intelligence like our parents, but becasue of how I’m not just as smart as my parents and nor is my sister, it would make sense that the environment that we grew up in (which has always been school first!) would affect us like that. Great post!

  11. Max Says:

    Wow, good post. I agree with Ms. Baker, about the polygenic trait part. I mean how could one gene hold all the intelligence that has been passed down from your parents. Also wouldn’t the parents of a special ed kid be ‘dumb’. Well I was a little confused so went and did some research and this is the website i thought provided great examples and evidence

    http://sg.answers.yahoo.com/question/index?qid=20070117072939AAqeKxj&show=7

  12. Miss Baker Says:

    Stevie – how are you not as “smart” as your parents? Where is your evidence for this? Grades? In a couple of days I’ll publish a post with evidence that shows success in school and life has less to do with being “smart” and more to do with how hard you work for it.

  13. Matt Says:It is true that work ethic has everything to do with it.Albert Einstein said,”It’s not that I’m so smart, it’s just that I stay with problems longer.” This just shows that those who are lazy and give up do not have the drive to succeed.http://www.brainyquote.com/quotes/quotes/a/alberteins106192.html
  14. Danny Says:

    Hmm this is interesting. I can sort of understand this and it would be neat to find out what kind of gene is passed down for intelligence. However, this does not make too much sense for me. My mom went to Harvard and Stanford, which alone says that she is pretty smart, and my dad is really intellegent. BUT, there is me, who is not the brightest bulb on the tree. I mean i hope that i get some of their brains later on, because i could surely use them!!

  15. Kristen Says:

    this makes alot of sence cause whenever people say oh your look/act exactly like you mom/dad i always wondered if you could get smarts from them to! good job lauren! i so have a question though. why do we get genes from one parent mostly then both?

  16. sebastiana Says:

    I think that yes your parents play a role in your passing intelligence in you however its you thats basically in school so you have a bigger role. I mean my parents are extremly smart and I am not as smart but my older brother is majoring in areospace and egineering and has been smart in math since forever. Where as for me I am very clueless about math. I personally think that it has to do with the enviroment your growing up in now ( whether its smart or dumb) and your parents ( not as much).

  17. lacey Says:

    Intresting post Lauren! However, i do have to say that even though you intellegence maybe somewhat inherited, you still have to put forth effort, in order to suceeded! For example, there was a set of twin sisters at my school last year, but they were completely different as far as their grades! One of them had all honors classes, and still mananged to make all A’s, while the other had regular classes, and barely passed two of them! This obviously shows that one was lazy and the other put forth a ton of effort! They both are pefectly capable of exceling in school, if they wanted to, but only one of them chose to pursue it!

  18. Kristen Says:

    i was thinking about what stevie was saying and….i think he is mainly right. i mean everyone does have FULL potential to make good grades in school…but yes it does matter whether we are smart or not but also…school puts alot on pressure on us as well. like basically GRADES are our whole life. and some people care and some people dont….im the youngest in my family and my sister is exactly like my dad good grades and everything and i was telling my mom about this post and she took out her old report cards and they we’re almost exactly like my past….so i do believe after this that it is genetics and like stevie said your enviornment as well.

  19. Morgan Says:

    I never knew that! Now I have an excuse for my grades! Just kidding! haha but trust me that explains a lot! But as most poeple said people still have a chance at getting good grades it just might be challenging for the poeple who don’t have that gene. Is that why there is always those really smart poeple in the grade that don’t even study and get good grades but those who study really hard and dont?

  20. Miss Baker Says:

    Morgan – are those that are studying that hard studying the right things? Students often don’t know how to study well. I always tell my students who have spent hours cramming THE NIGHT BEFORE the exam that they just WASTED several hours.

    Also, for the students that are making great grades without studying – how challenging is the material? The ironic thing is that as they get older and run into more challenging classes, they are actually HURT by their previous easy successes because they get it in their head that they are “smart” and therefore shouldn’t have to study very hard. So they get frustrated when they start to do poorly.

  21. Sydni Says:wow i dont know who to beleive in this miss baker or the other guy. but really i think you are both righ. i think some of it is inherited and some we expand for our selves. i know there is some study saying that you should do things that you would not want to do because it makes connections in your mind that have not been made before so more of your brain is working together.
  22. Mayur Says:

    Very pleased to find my photo here. Thanks for the credit :)

  23. Skye Says:

    Ok, I partially believe this is true and false. For one, my dad is a very intelligent and intellectual type of person; I just do not know how he does it! So is his father, my grandpa. But then my mother is the complete opposite of those two. She never did particularly well in school and is not has intelligent. So since both of my parents are completely opposites when it comes to book smart what does that make me, average? Do they level each other out?

    My other side is anyone who has a normal brain meaning they do not have any brain diseases can be inelegant or good at something if they study and practice. It is not only that being intelligent is hereditary; you have to put effort into becoming smart. Unless for example you have Down syndrome you can for sure succeed in whatever you want!

    http://serendip.brynmawr.edu/biology/b103/f03/web1/rkallon.html

  24. Hope Says:

    Wow, that makes a lot of sense. I have always heard of people getting most of their intelligence from their parents but I never quite knew if it was correct. I was told that you only get fifty percent of your intelligence from your parents, not seventy-five. I was really suprised to see that.

    Even if you are born from not so intellectual and brillant parents, you can still apply yourself and change your future. People who have parents that got C’s and D’s can still study and work hard and get good A’s and B’s.

  • Neena

    This question is an intriguing question. Understanding how intelligence comes about is an idea that

    However, there are some glitches in this post. Firstly, Dr. Bouchard’s work was referred to as a ‘recent study.’ However, the date that is posted on the NY Times article concerning Dr. Bouchard was 1990. Thus Dr. Bouchard’s data, according to the references given in the post, was 17 years old (date of results-date of student blog publishing.) I do not believe it is accurate to center an argument around data that is 17 years old because scientific methods of testing have grown more sophisticated (ie the advent of computers, advanced brain scanning tools, etc).

    In that article, it is also unclear how Bouchard concluded that IQ scores were attributed to genes. How did he make this conclusion? The actual thought process of how he reached that conclusion is not outlined in the article. Conversely, Bouchard could have easily concluded that IQ scores were attributed to the environment (ie different schools). But how does he determine this with personality and intelligence tests? What is this enormous amount of evidence he speaks of?

    It is also questionable how accurate his tests were in measuring personality and intelligence. A major flaw was this:

    “He found more than 100 separated pairs and subjected them to a battery of personality tests and intelligence tests, ASKING HOW MUCH OF THEIR SIMILARITIES IN INTELLIGENCE AND PERSONALITY TRAITS WAS DUE TO INHERITANCE AND HOW MUCH WAS DUE TO THE ENVIRONMENT.”

    This was unclear as well. Was he asking the test subjects to determine how much they thought their personality and intelligence contributed to inheritance or the environment? If so, then how would Dr. Bouchard verify his results? repeat his experiment? How old were these twins? Were they old enough to understand the questions or cognitively developped enough to articulate or even understand why they do the things they do?

    Bouchard also did not use a large testing sample in the experiment.

    In the post, it says that Bouchard followed up with a study in 2001. However, Bouchard did not conduct a study then. The scientist referred in that 2001 study link is Dr. Thompson.

    I thought the MRI experiment was fascinating. I especially thought the evidence showing that language areas of the brain are heritable was interesting. Language helps us communicate, articulate our ideas and understand material. Following this line of thought, it makes sense to me that language areas and frontal regions play a huge role in cognition. If you have a heightened ability to understand and learn language, then your method of coding, storing and processing information will be unique and different from others.

    I found it surprising that the study stated that the environment (ie personal experiences) played a neglibeale role in shaping the frontal structure. One would assume that that wouldn’t be the case because sometimes, he or she feels like they would not be the same person without having been influenced by a special person or role model. Perhaps the twins in this study were not exposed to drastically different types of people and environments?

    Also, what were the two different environments in both experiments? Different schools? Different cities? States? Neighborhoods?

    Needless to say, I think this question ignites curiousity. I believe that intelligence is a combination of genes and environment. I think that to be ‘intelligent’, one has to nurture what nature endows.

    The comments from other bloggers about a combination of hard work and inborn intelligence also makes me think of another question: is a hard work ethic inherited?

  • Irene

    I thought that it was pretty amazing to read that 70 percent of intelligence is inherited, because that means then there will be so much little possibility to people with worse grade to improve even if they try hard. Also, in the article, Dr. Bouchard Jr. says that “We’re saying that nothing in the study tells us that intervention is not a possibility, but we have to pay attention to the unique talents of each child, “. This quote made me thought that it means that inheritance will affect child’s talent which does not necessarily has to be grades in school.

  • Gilmor

    I enjoyed your post very much, although I too am not convinced about the role of genetics in intellingence. I would like to refer you to “Mindset” by Carol Dweck. Dweck is a psychologist who tested the correlation between the “intellingence phenotype” and the positions one holds regarding intelligence.

  • john

    Enjoyed the article and fully agree. To a large extent intelligence (the ability to learn is inhereted}. Memorizing large volumes of facts and data do not make a person intelligent,a book can be compiled to do this. The ablilty to understand and apply,extrapolate and interpolate are more so the signs of intelligence. Many professionals make the grade and manage to do well in their profession a very few are able to acheive great advancements with the same education so what is intelligence.

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