[coglanglab (OP)]

Nearly a century ago Alfred Adler http://en.wikipedia.org/wiki/Alfred_Adler [nofollow] suggested that one's birth order (oldest, middle, youngest) affects one's personality. The evidence is increasingly clear that it does affect performance on IQ tests (it tends to go down for younger siblings, on average, if only slightly), but the evidence for its effect on personality has been mixed.

Many of the experiments that have failed to show birth order effects on personality quantified personality in terms of a psychometric test such as Meyer-Briggs or Big Five. There is some controversy as to whether personality tests are particularly accurate. If they aren't accurate or reliable, then finding a correlation between their scores and birth order would be unlikely.

Although our personality tests may not be very accurate, individual humans are pretty good at judging the personality of others. So I tried to think of a way to use people's intuitions about a person in order to measure that person's personality and correlate it back to their birth order. If that were possible, then perhaps that would show the effect of birth order that other experiments have failed to show. If no effect is found, then it becomes even more unlikely that birth order effects are real.

Once I found a method, the next step was to test it. I am running an survey right now to test this hypothesis. I would really appreciate it if you participated. You can find it at the Cognition and Language Laboratory http://coglanglab.org/BirthOrder [nofollow].

(To the moderator: Yes, this is a type of advertisement, but I think that the topic would be interesting to people at this forum. Plus, there is more information about current research at that site that may interest readers.)

[ukmicky]

(To the moderator: Yes, this is a type of advertisement, but I think that the topic would be interesting to people at this forum. Plus, there is more information about current research at that site that may interest readers.)

I've had a look at the web site and cant find anything which we would object to .

This subject could be of interest to some people so maybe this topic rather than being hidden away in  new theories section could be moved to somewhere better.

[another_someone]

I agree, that a theory that is nearly 100 years old is scarcely new.  More to the point, this thread is not about evangelising a theory, but it is about ongoing research.

I shall move it to Physiology and Medicine.

[coglanglab (OP)]

Ukmicky, if you think there is a better place to move it, by all means do. Thanks for visiting the site.

[kdlynn]

i for one am very interested as i am both an only and the oldest child

[Karen W.]

I am middle!

[another_someone]

Have just taken your test, but am not at all convinced about your premise.

I would agree that people will associate with other people who share a similar value set, but not necessarily of a similar personality.

On the other hand, my anecdotal observations are that people will also tend to associate with people of a similar IQ (and in particular, women tend to have great difficulty if they marry a man of lower IQ to themselves, which will tend to mean that high IQ women will have a greater likelihood of marrying a high IQ man, although the converse is not always as true).  Given that we already have evidence that first borns are differentiated from their siblings by their IQ, have you made any allowances that what your method is really measuring similarity of personality, or just another way of measuring similarity of IQ?

[coglanglab (OP)]

Have just taken your test, but am not at all convinced about your premise.

I would agree that people will associate with other people who share a similar value set, but not necessarily of a similar personality.

On the other hand, my anecdotal observations are that people will also tend to associate with people of a similar IQ (and in particular, women tend to have great difficulty if they marry a man of lower IQ to themselves, which will tend to mean that high IQ women will have a greater likelihood of marrying a high IQ man, although the converse is not always as true).  Given that we already have evidence that first borns are differentiated from their siblings by their IQ, have you made any allowances that what your method is really measuring similarity of personality, or just another way of measuring similarity of IQ?

That's a good point. This is the third experiment in a study that was started before the IQ results were as clear. I'm going to see what the literature says about self-association among people with similar IQ. I'm also not sure about the exact distribution of the the IQ results among oldest, middle, youngest, only, and it's possible the results of my experiments will show a different pattern. Or the same. We'll see.

[RD]

Nearly a century ago Alfred Adler suggested that one's birth order affects one's personality.

Boys with older brothers 'more likely to be gay'
Last Updated: 2:26am BST 27/06/2006

Boys are more likely to grow up gay if they have older brothers - because of biology, rather than upbringing.

Ten years ago researchers made the startling discovery that the more elder brothers a boy has, the greater chance he has of being homosexual.

For each additional brother that precedes him, a boy's likelihood of growing up gay increases by a third.

At the time it was speculated that this was because boys with elder brothers are psychologically affected by their family dynamics in a way that influences sexual orientation.

But new research published today in the journal Proceedings of the National Academy of Sciences (PNAS) shows this is not the case.

The link between fraternal birth order (FBO) and being gay only exists when brothers have the same biological mother.

Having older adopted or stepbrothers with a different mother made no difference to whether a boy turned out gay or straight. However, brothers sharing the same mother but raised in a separate family still exerted an influence.

The discovery was made by Dr Anthony Bogaert, from Brock University in St Catherines, Canada, who with a colleague first uncovered the birth order link with homosexuality.

Dr Bogaert did not conclude what biological factors influence the sexuality of homosexuals with elder male siblings, but previous research has shown that genetics and the womb environment can have a major impact on sexual preferences in both men and women.

http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/06/26/ugay.xml&sSheet=/news/2006/06/26/ixnews.html


 

[coglanglab (OP)]

I've seen this research about birth order an homosexuality. I understand it's fairly controversial, although the paper just quoted was published in in PNAS, which is a good journal.

I wrote a little bit more about birth order effects on my new blog, so in case anybody is interested: http://www.scienceblog.com/cms/does-birth-order-affect-personality-13956.html [nofollow]

[another_someone]

I've seen this research about birth order an homosexuality. I understand it's fairly controversial, although the paper just quoted was published in in PNAS, which is a good journal.

I wrote a little bit more about birth order effects on my new blog, so in case anybody is interested: http://www.scienceblog.com/cms/does-birth-order-affect-personality-13956.html

I read your blog, but as a mere layman, with no special knowledge in the area, I would disagree with a few issues on it.

Firstly, you state that IQ is not personality.  I would suggest that IQ has an impact on personality, even though you may be right in saying that we do not use it as a measure of personality.

Secondly, you suggest that proof of a birth order effect would undermine the nature side of the nature/nurture debate.  I would disagree with this categorically.  There are both maternal prenatal (biological) influences to be taken into account, as well as epigenetic influences, as well questions concerning how random the selection of the sperm that fertilises the egg really is.  All of these are biological (i.e. nature) effects that may be influenced by birth order.

[coglanglab (OP)]

Secondly, you suggest that proof of a birth order effect would undermine the nature side of the nature/nurture debate.  I would disagree with this categorically. 

I would also disagree! Currently, there are people (such as Steve Pinker) very seriously arguing that nurture has essentially no role in personality. At least, that's how I read them. So I'm not trying to argue that nature has no role. That would be patently ridiculous, based on twin studies. The question is whether nurture has any role.

[dkv]

From TSP point of view : Elder the son or daughter greater is the responsibility. We like to invest in the earliest available opportunity.

[WylieE]

Hi Coglanglab,
 I took the test, but at the end on "click to learn more about this experiment" my window shut down.  Is there anyway to get to the information on the experiment without taking the test again?
Thanks

[coglanglab (OP)]

Hi Coglanglab,
 I took the test, but at the end on "click to learn more about this experiment" my window shut down.  Is there anyway to get to the information on the experiment without taking the test again?
Thanks

Sure, email coglanglab@coglanglab.org.

[chris]

(To the moderator: Yes, this is a type of advertisement, but I think that the topic would be interesting to people at this forum. Plus, there is more information about current research at that site that may interest readers.)

That's alright - we use the "no follow" tag anyway, so search engines are instructed not to follow links to external sites from this forum. Since the content contributes to the discussion here this is fine. If you decide to go into selling shoes, mobile phones, watches or cheap generic drugs, then things might be different...!

However, on a different note, can you just offer us some reassurances about what you are doing with the data you are collecting - for the purposes of safeguarding identities and personal information etc? i.e. that you are not collecting IP addresses or any other data that may be tracked back to an individual.

Thanks,

Chris

[coglanglab (OP)]

You can read about our privacy politicies here [nofollow].

Just a few technical points: Websites typically automatically log IP addresses. It's part of the server log. And if you go to a website that uses a hits counter, it's fairly likely it's saving your IP address. Basically, you should assume that your IP address is being saved at every website you visit. It may not be, but it's better to assume that it is.

The good thing is that an IP address isn't always very useful for tracking an individual person. IP addresses track computers, not people. Many people's computers are on networks with dynamically-assigned IP addresses, which means every so often -- sometimes every few seconds -- your IP address changes. So an IP address is not always very useful for finding people.

So, yes, we do record IP addresses. No, they aren't shared with anybody. We use them to track potential vandalism (somebody repeating an experiment over and over and over without admitting to it). In any case, although all the experiments are anonymous, we don't ask any information that anybody is likely to have a burning desire to keep quiet. Unless you are really touchy about your age.

That said, if you find information being asked that you don't want to share, I'd like to know about it.

[another_someone]

If you really don't want your IP address tracked by a server, then use a proxy server (although the caveat to this is that the proxy server site can track your IP address, but the end site you are logging on to only sees the IP address of the proxy server - your choice).