[precisioncoder]

Very interesting.

I started thinking about possible other reason's this could occur and checked into the data about the Norwegian study. The data was all from mandatory conscription so it couldn't be tainted could it?

Guess again.

At the same time that IQ started dropping Norway changed their conscription policy...

https://en.wikipedia.org/wiki/Norwegian_Armed_Forces

"In practice recruits are not forced to serve, instead only those who are motivated are selected.[14] In earlier times, up until at least the early 2000s, all men aged 19–44 were subject to mandatory service, with good reasons required to avoid becoming drafted."

Hmmmm so IQ in the tested cohort started dropping when it was only tested in people who chose to take part in Military service rather than all 17-18 year old males?

That seems like it could have another explanation...

EDIT:

So it seems I missed some info ->

I went back and looked at the data in the study to see whether it used the preliminary research or only for successfully recruited candidates and discovered this:

"Cohorts born before 1962 were subject to a different scoring norm, and cohorts born later than 1991 faced a radically different conscription process with less than 50% invited for in-person testing after completing a web-administered survey. As a result, representative data are not available for later birth cohorts. Data for immigrants are excluded as information on full family size and exact birth order is of lesser quality, while selection into scoring is markedly different as immigrants typically do not face mandatory conscription testing but need to self-select into conscription."

So it seems the preliminary examination does not include enough information or the conscription in general has changed to radically for that information to be reliable.

After more investigation it seems that basically they're saying that from 1980 - 1993 IQ rose, then fell again from 1993-2007 reaching roughly the same levels as previously.

All data after that is tainted as too much has changed in the data source (conscription).

However one very important point about this is that all data is pre-smartphone.

[bshipp]

This explanation isn't nearly as fun as all the wild speculation we're all posting below you.

+1 for actually hunting down the original study and interpreting it.

-1000 for spoiling our self-righteous party.

[notus]

Actually they didn't read it well

[bshipp]

They read it well enough to generate a testable hypothesis about the underlying data. He or she should be commended, not criticized.

Even with the resulting edit there appears to be, at least to me, a clear need for additional investigation utilizing non-Norwegian conscription data before the original research question can be validated.

[precisioncoder]

True enough, however through my mistakes we have established that all self righteous theorizing should take into account that the data is pre-smartphone ;)

[nudq]

> While 63,841 men and women were called in for the examination of persons liable for military service in 2012 (mandatory for men), 9265 were conscripted

Sounds like all men are tested, not all serve.

[precisioncoder]

Good catch... I wasn't reading thoroughly enough...

I went back and looked at the data in the study to see whether it used the preliminary research or only for successfully recruited candidates and discovered this:

"Cohorts born before 1962 were subject to a different scoring norm, and cohorts born later than 1991 faced a radically different conscription process with less than 50% invited for in-person testing after completing a web-administered survey. As a result, representative data are not available for later birth cohorts. Data for immigrants are excluded as information on full family size and exact birth order is of lesser quality, while selection into scoring is markedly different as immigrants typically do not face mandatory conscription testing but need to self-select into conscription."

So it seems the preliminary examination does not include enough information or the conscription in general has changed to radically for that information to be reliable.

[mirimir]

That's a confusing Wikipedia article. It also says:

> Since 1985, women have been able to enlist for voluntary service as regular recruits.[citation needed] On 14 June 2013, the Norwegian Parliament voted to extend conscription to women.[15] In 2015 conscription was extended to women making Norway the first NATO member and first European country to make national service compulsory for both men and women.[16] There is a right of conscientious objection.[citation needed]

So at least since 2015, all men and women called in were apparently tested.

[lordalch]

Valar Dohaeris? Wait, nevermind...

[ramblerman]

Wow, that's ridiculous they didn't consider that, or chose to ignore it.

Good find.

[notus]

As others have pointed out, they missed a very crucial detail, and then didn't edit their post for some reason.

[precisioncoder]

Thanks for the heads up, I went back and edited my comment.

[BethGagaShaggy]

Figure 1 A shows a the trends in cohort IQ for the study, and it only goes roughly from the early 1960s to the early 1990s, which is the whole of the comparable period, and it does rise and fall within that period. I just don't know what you're on about.

https://www.pnas.org/content/pnas/115/26/6674.full.pdf

[raxxorrax]

While I think the comparability of IQ test to the past or other countries is very rudimentary, this sounds like this could be a huge factor at least.

[verttii]

We need people like you to be journalists.

[redleggedfrog]

Seems like your IQ isn't a problem...