First-born children likely to have higher IQ than siblings

[Maciamo]

BBC News : First-borns have higher IQ scores

The child raised as the eldest in a family is likely to have a higher IQ than his or her siblings, work reveals.

A Norwegian team found first born children and those who had lost elder siblings and had hence become the eldest, scored higher on intelligence.

The link, reported in Science, was found by looking at more than 250,000 male Norwegian conscripts.
...

Supporters of the theory argue the eldest child gets more undivided attention from their parents from an early age.

Others claim differences occur in the womb before birth because with each subsequent pregnancy the mother produces higher levels of antibodies that may attack the foetal brain.

While others claim the relationship between birth order and intelligence is false, being biased by family size - historically, couples with lower IQs have tended to have more children than couples with higher IQs.
...

"In addition, the tendency for first-borns to occupy the niche of a surrogate parent, and to take on the role of the conscientious, self-disciplined and mature sibling may also explain why first-borns have higher IQs," he said.

I am glad people spend time doing this kind of research. There is still so much we do not understand about the human mind. The next step here will be to determine which of these factors is more determinant for IQ. I believe it is partly because of the mother's antibodies, and partly because of the more undivided attention.


In the same line, other research have found that men have higher IQ's than women in average.

Dr Irwing, a senior lecturer in organisational psychology at Manchester University, told the Today programme on BBC Radio Four the study showed that, up to the age of 14, there was no difference between the IQs of boys and girls.

"But beyond that age and into adulthood there is a difference of five points, which is small but it can have important implications," he said.
...
There were twice as many men with IQ scores of 125, for example, a level said to correspond with people getting first-class degrees.

At scores of 155, associated with genius, there were 5.5 men for every woman.

This is most likely caused by male hormones, which have for effect to specialise the brain for more logic and rational tasks. However, it does not mean that men are more intelligent than women overall, as female hormones have other advantages, especially regarding communication and EQ.

I looked at the comments at the bottom of the article, and the first person says :

My reaction, coming from a family with a tradition of women who achieve very highly in maths and sciences, is weary disgust.

I personally dislike that kind of reaction, because it is a fact that academic achievements require hard work and commitment, not high IQ. A higher IQ might help. But it's just like being predisposed for sports. If one doesn't practice, natural talent comes to nothing.

On the other hand, anybody with a slightly above average IQ can achieve very well at school or at work with the right motivation.

In fact, other studies have shown that people with exceptionally high IQ tend to perform less well academically, because they tend to get bored too quickly during lessons and they are less sensitive to rewards (what's so great to be praised by someone less intelligent than you, huh ?).

[Maciamo]

Here is another related topic : BBc News : Breast milk 'does not boost IQ'

Breastfed babies are smarter because their mothers are clever in the first place, not because of any advantage of breastfeeding itself, a study suggests.

Researchers found breastfeeding mothers tended to be more intelligent, more highly educated, and likely to provide a more stimulating home environment.

This goes in accordance with other researches that found that children born :

- from a mother 30 years old or older
- in families with a higher socio-economic status
- in families with few children
- in families with a lot of books at home

... all have higher IQ's in average. This is simply because women who have children after 30 are usually better educated; because families of higher socio-economic status are usually better educated or have higher IQ's; because more educated people tend to have less children; because families with more books at home tend to be more intellectual...

Breastmilk does not boost IQ anymore than being richer or having an older mother does. What really matters is how you parents are (how educated, how intelligent, how dedicated to their children).

Tests on identical twins separated at bith have also shown that IQ is highly hereditary (thus more genetic than environmental, although both play a role).

[Kinsao]

This is very interesting research. I was an only child, but also female so maybe that kind of balances itself out!

[Nasturtium]

How interesting...I have examples in my family that validate that theory, and examples that refute it. Clearly it's a complex interaction of factors, but it makes sense. On a related note, I watched a show on BBC last night about a gay man searching for biological reasons for his sexual preference. Ultimately it was determined that for each older brother a man has, it increases his chance of being gay substantially. The theory being, the mother develops antibodies that attacks subsequent male fetuses, leading to homosexuality.

[Mitsuo]

I have heard this as well. But I heard this was wrong and that the youngest child is likely to be the smarter one, mainly due to observing their older siblings.

[Maciamo]

I have heard this as well. But I heard this was wrong and that the youngest child is likely to be the smarter one, mainly due to observing their older siblings.

You could argue that couples who are too young and immature when they have their first child will not take care of their first child as well as the others, because their learn with experience.

You could also argue that having older siblings doesn't matter if you send the child to nursery school from 6 months old to socialise with other kids.

It ultimately depends on many factors. Socio-economic status has been shown to correlate positively with IQ, probably because children are better fed, live in a more peaceful environment, have more toys, and more intellectual parents will talk more to them. But even the quality of the environment can vary over time (in better or worse) inside the same family.

More importantly, the gene combination inherited by each child inside the same family aren't the same, and intelligence being highly genetic, high IQ will go to the one that "wins the genetic lottery" (just as for good looks). If both parents are exceptionally intelligent, then each child has higher chances to be too.

[childfont]

This is just a myth I think depends on individual child's growth which would help in generating of higher IQ.

[ultralars]

This is probably true, my oldest brother( we are 5 children) have an IQ of 155, while i being the youngest sibling only have 125.

[leemadison11]

I guess its because of the fertility of the women, a child born early would be born at the younger age of the women as compared to her child younger than her older child. So if a women bear a child at 25 and at 30, then it would surely make a difference. I am just guessing, i don't know how true could it be.

[hope]

Could this not be the old Nature or Nurture question? I think first born children usually get more time from their parents or the primary carer and this time involves lots of play eg. reading, learning colours or counting and being encouraged to speak (I do not say this is always the case in all families but in general) Thus the child develops a good basic skill package which may allow it to view learning in a positive way and so adapt to school without trauma. When the second or third child comes along time is at a minimum and such play games are less and the child is left more to play alone or watch television. Therefore it may not be that the first child is more intelligent , merely that it has benefited from the fuller interaction it has received when younger.

[jinn]

i am the youngest one in my family, my brothers are smarter than me