Saturday, October 20, 2012

Intelligence and fertility by class, over time

Channeling Charles MurrayRandall Parker comments on the increasing social stratification that has come to define the contemporary Western world:
This isn't the 1950s when people could expect to pair up with a husband or wife and get a factory job that put them at similar status level to a large portion of the total population. We've got a much wider spread of classes and far more cognitive sorting. The poor are dumber on average and the upper classes are smarter on average. The classes have less in common: less shared understanding, fewer shared values, fewer shared experiences with cultural products such as TV and radio shows.
On the one hand, inequality has been public enemy number one for multiple generations now. On the other hand, one major consequence of a shrinking world is that cognitive sorting keeps getting easier to do and is continually approaching ubiquity in practice.

I wondered what insights the GSS might offer. The survey has a question for which respondents are asked which of four social classes they feel they belong to--lower, working, middle, or upper. The following graph shows mean wordsum scores by self-identified class membership over time. The three variables have not been cross-referenced for every year the survey has been conducted (not sure why, as each has independently been included since its inception, but it is what it is), which is why the years displayed jump around as they do. To avoid issues of English language fluency, the foreign-born are excluded:


Steady as she goes. Of course, this doesn't necessarily speak to potential changes in material or cultural class differences over the last several decades per se, but the cognitive sorting by class isn't blatantly obvious, at least not by this measure.

And because detecting dysgenic trends is a hobby horse here, the mean number of children by class over time:


Sample sizes are smaller for the lower and upper classes (self-assessment rates split about 5%-45%-45%-5%) so their respective lines bounce around more, but the pattern over time is pretty consistent--higher class means somewhat lower (and later) fertility, and people across the social spectrum are having fewer children today than their parents had.

GSS variables used: BORN(1), YEAR, CLASS, WORDSUM, CHILDS

5 comments:

IHTG said...

Lifetime sexual partners by class over time?

Anonymous said...

It would be interesting to redo that last graph of fertility while excluding all those who report zero children. I say this because it shows us how many children each child is growing up with and sees as normal. Also, those who have no children are the Darwinian dead ends. Those that have at least one are passing on genes and environment.

JayMan said...

Anonymous, but if you do that, you also need to have some sort of acknowledgement of the proportion of childless people in each class, because that affects the overall fertility of these classes.

Dan said...

Does this control for age? Upper classes generally have kids later than lower classes I think.

JayMan said...

Also see this recent post of mine:

Sure it does… « JayMan's Blog