Results 1 to 3 of 3

Thread: Twins Have Lower IQs Than Singleton Relatives

  1. #1
    Funding Member
    "Friend of Germanics"
    Skadi Funding Member

    Blutwölfin's Avatar
    Join Date
    Feb 2005
    Last Online
    2 Weeks Ago @ 04:53 PM
    Status
    Available
    Ethnicity
    German
    Ancestry
    Skåne and North Frisia
    Country
    Iceland Iceland
    Gender
    Family
    In a steady relationship
    Posts
    4,084
    Thanks Thanks Given 
    13
    Thanks Thanks Received 
    61
    Thanked in
    42 Posts

    Twins Have Lower IQs Than Singleton Relatives

    Twins have lower IQ scores than singletons, researchers here reported, and the reason may be low birth weight and reduced gestational age.

    A study of more than 10,000 children born in Scotland a half century ago found that by age seven, the mean IQ score of the twins was 5.3 points lower (95% confidence interval 1.5 to 9.1) than that of their singleton family members.

    By age nine, the IQ gap was even greater, with a mean IQ score that was six points (1.7 to 10.2) lower than their singleton relatives, Georgina A. Ronalds, M.Sc., of the London School of Hygiene and Tropical Medicine here and colleagues reported in the Nov. 18 issue of British Medical Journal online.

    Adjustment for birth weight and gestational age attenuated the IQ difference between the two groups of children; at age seven, the difference in mean IQ was 2.6 points (95% CI, -1.5 to 6.7), and at age nine, it was 4.1 points (95% CI, -0.5 to 8.8).

    "Cognitive ability is strongly associated with educational attainment, adult socioeconomic position, and mental and physical health," wrote Ronalds and colleagues. "A cognitive deficit in twins of this magnitude is therefore clearly of long term importance."

    The investigators studied data on 9,832 singletons and 236 twins born into more than 8,000 families in Aberdeen, Scotland between 1950 and 1956.

    All children underwent two cognitive tests within six months of their seventh and ninth birthdays. The first test consisted of recognition questions and understanding the differences between sets of line-drawn pictures. The test they took at age nine measured reading ability. Data from both tests were included in the IQ analysis.

    The research team also obtained data on the mother's age at the time of delivery, the child's birth weight, gestational age at birth, and the father's occupational status. They also obtained information on the number of older siblings (excluding co-twins) in the participants' families.

    Overall, singletons had significantly higher mean IQ scores than twins (P<0.001).

    Not surprisingly, twins were more likely to be smaller at birth than singletons. Forty-seven percent of the twins weighed less than 5.5 pounds at birth compared with only 4.2% of the singletons. More than 26% of the singletons weighed more than eight pounds at birth compared with only 0.9% of the twins who weighed as much.

    Twins were also born earlier at gestation than singletons. Nearly 38% of the twins were born between 33 and 37 weeks gestation compared with 6.1% of the singletons.

    When looking at just the twin cohort, the researchers found at age seven, twins who had weighed less than 5.5 pounds at birth had a mean IQ score of 97.3. By age nine, these twins' mean IQ score was 100.9.

    However, twins who weighed 6.5 pounds at birth showed a mean IQ score of 107.5 at age seven and a mean IQ score of 109 at age nine. Gestational age showed similar findings.

    Sex, maternal age, and the number of older siblings "had little effect on these differences," the authors wrote. "Most importantly, we have also shown that differences in IQ between twins and singletons of the same order are found within families. These differences persisted after adjustment for maternal age and number of older siblings."

    The authors said it was possible some postnatal environmental factors may contribute to IQ disparities. However, they lack any data to confirm this.

    The investigators also acknowledged these results were based on children born a half century ago and it's possible studies of a more contemporary cohort would yield different results.

    Nevertheless, the authors concluded that truncated prenatal growth and shorter gestations of twins "may explain an important part of their lower IQ in childhood."


    Source
    Lík börn leika best.

  2. #2
    Member ikki's Avatar
    Join Date
    Jan 2005
    Last Online
    Friday, September 12th, 2008 @ 06:56 PM
    Subrace
    East Baltid
    Location
    Finland
    Gender
    Age
    41
    Occupation
    Accountant
    Politics
    White Supremacist
    Religion
    Learning Odinist
    Posts
    439
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts
    So its about birth weight anyway, rather than twindom.
    Also, better get that checked, it seemed like twins with proper weight were smarter...

    ..which means what, feed all twin-mothers-to-be up on lots of sugar..? (-> insulin -> bigger babies)?? :
    Ignored: Nicholas

  3. #3
    Senior Member Thruthheim's Avatar
    Join Date
    Oct 2005
    Last Online
    Saturday, March 31st, 2007 @ 03:15 PM
    Subrace
    Skando-Nordid->CM
    Country
    England England
    Location
    East of Pennines-South of Humber
    Gender
    Posts
    1,330
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    4
    Thanked in
    4 Posts
    Quote Originally Posted by Blutwölfin
    Twins have lower IQ scores than singletons, researchers here reported, and the reason may be low birth weight and reduced gestational age.

    A study of more than 10,000 children born in Scotland a half century ago found that by age seven, the mean IQ score of the twins was 5.3 points lower (95% confidence interval 1.5 to 9.1) than that of their singleton family members.

    By age nine, the IQ gap was even greater, with a mean IQ score that was six points (1.7 to 10.2) lower than their singleton relatives, Georgina A. Ronalds, M.Sc., of the London School of Hygiene and Tropical Medicine here and colleagues reported in the Nov. 18 issue of British Medical Journal online.

    Adjustment for birth weight and gestational age attenuated the IQ difference between the two groups of children; at age seven, the difference in mean IQ was 2.6 points (95% CI, -1.5 to 6.7), and at age nine, it was 4.1 points (95% CI, -0.5 to 8.8).

    "Cognitive ability is strongly associated with educational attainment, adult socioeconomic position, and mental and physical health," wrote Ronalds and colleagues. "A cognitive deficit in twins of this magnitude is therefore clearly of long term importance."

    The investigators studied data on 9,832 singletons and 236 twins born into more than 8,000 families in Aberdeen, Scotland between 1950 and 1956.

    All children underwent two cognitive tests within six months of their seventh and ninth birthdays. The first test consisted of recognition questions and understanding the differences between sets of line-drawn pictures. The test they took at age nine measured reading ability. Data from both tests were included in the IQ analysis.

    The research team also obtained data on the mother's age at the time of delivery, the child's birth weight, gestational age at birth, and the father's occupational status. They also obtained information on the number of older siblings (excluding co-twins) in the participants' families.

    Overall, singletons had significantly higher mean IQ scores than twins (P<0.001).

    Not surprisingly, twins were more likely to be smaller at birth than singletons. Forty-seven percent of the twins weighed less than 5.5 pounds at birth compared with only 4.2% of the singletons. More than 26% of the singletons weighed more than eight pounds at birth compared with only 0.9% of the twins who weighed as much.

    Twins were also born earlier at gestation than singletons. Nearly 38% of the twins were born between 33 and 37 weeks gestation compared with 6.1% of the singletons.

    When looking at just the twin cohort, the researchers found at age seven, twins who had weighed less than 5.5 pounds at birth had a mean IQ score of 97.3. By age nine, these twins' mean IQ score was 100.9.

    However, twins who weighed 6.5 pounds at birth showed a mean IQ score of 107.5 at age seven and a mean IQ score of 109 at age nine. Gestational age showed similar findings.

    Sex, maternal age, and the number of older siblings "had little effect on these differences," the authors wrote. "Most importantly, we have also shown that differences in IQ between twins and singletons of the same order are found within families. These differences persisted after adjustment for maternal age and number of older siblings."

    The authors said it was possible some postnatal environmental factors may contribute to IQ disparities. However, they lack any data to confirm this.

    The investigators also acknowledged these results were based on children born a half century ago and it's possible studies of a more contemporary cohort would yield different results.

    Nevertheless, the authors concluded that truncated prenatal growth and shorter gestations of twins "may explain an important part of their lower IQ in childhood."


    Source
    Cracking

    I know a few twins, im sending this article to them asap
    Tired

Similar Threads

  1. Beauty and Brains Do Go Together: Study Claims Good-Looking Men and Women Have Higher IQs
    By Nachtengel in forum Bio-Anthropology & Human Variation
    Replies: 16
    Last Post: Saturday, February 5th, 2011, 11:42 AM
  2. The 'Terrible Twins' of the Royal Navy
    By GroeneWolf in forum Netherlands & Flanders
    Replies: 0
    Last Post: Tuesday, September 1st, 2009, 06:00 PM
  3. African and American blacks have equally low IQs, environmental factors not important
    By Tennyson in forum Psychology, Behavior, & Neuroscience
    Replies: 19
    Last Post: Thursday, December 14th, 2006, 02:27 AM
  4. "Low IQs are Africa's curse"
    By Blutwölfin in forum Articles & Current Affairs
    Replies: 24
    Last Post: Tuesday, November 7th, 2006, 08:57 PM
  5. Low IQs 'shouldn't have children'
    By Phlegethon in forum Strategic Intelligence
    Replies: 23
    Last Post: Friday, May 14th, 2004, 04:08 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •