Brief: How does IQ predict vegetarian practices?

Our impression is that it's the smarter people who are more likely to practice vegetarianism to some degree. Go to a blue-collar picnic one weekend and a yuppy dinner party the next, and just ask which one had more vegetarian fare. At the former, we think of hamburgers and hot dogs, while we think of salad and risotto at the latter.

The GSS asks whether you refuse to eat meat for environmental reasons to varying degrees, or if you never abstain for such reasons. I've collapsed responses into refuse to eat meat to any degree (vegetarians) and never refuse to eat meat (omnivores). The pattern doesn't change if we look at the disaggregated data, but this makes the pattern easier to see. The GSS also gives a vocab test to roughly measure IQ. (I've collapsed those who got 0 to 2 words into one group just to keep sample sizes near 100 or greater.) Here is a graph that shows how likely a person is to be vegetarian to any degree depending on what their IQ is (red means veg):


This may shock us at first because vegetarianism almost strictly declines as IQ increases. Maybe we weren't considering representative samples of smarties -- maybe the more liberal or new age tribe among them goes vegetarian, while the conservative or traditional tribe goes for steak. I re-did the analysis looking only at liberals, and again only at conservatives, but the pattern holds up. Nor is there a strong relationship between vegetarianism and either income (meat is more expensive than corn, so that's worth looking at) or education level (this may affect your awareness of the treatment of animals, your exposure to philosophy classes, etc.). Strange as it may seem, there's something unique to smarts that makes you less likely to go veg.

There are the trend-bucking super-smarties, of course, but I'm inclined to believe this is a sort of counter-signaling -- adopting a lower-IQ practice to show that you can still do well even with such a handicap. The very smarts want some way to show that they have the analytical horsepower to have philosophical views on their diet, and at the same time look down their noses at the behavior of their immediate inferiors -- who serve such things as caviar, foie gras, and kobe beef at their parties -- so it's vegetarianism to the rescue!

GSS variables used: nomeat, wordsum, polviews, realinc, educ

How are religiosity and teen pregnancy related?

Razib points me to a new study showing that, controlling for various factors, states with greater religiosity scores tend to have higher teen birth rates. So, compared to more secular states, the states in the Bible Belt are more likely to supply underage guests for the Maury Povich show who shout at their parents and the audience that, "I don't care what you think -- I'm gonna have that baby!"

But does this state-level pattern hold up at the individual level or not? To be clear what the question is, it could be that it's primarily the non-religious girls who give birth as teenagers -- say, because both traits reflect an underlying wild child disposition -- and perhaps the religiosity of their community is a response to tame this problem. So, for whatever reason, some states might have a greater fraction of devil-may-care girls, which would cause the state to have a higher teen birth rate as well as a greater religiosity score. (These states would have more of a teen pregnancy problem to deal with, hence a greater community policing response via religion.)

Or the patterns could be the same at the individual and the state levels -- that is, there's something about a highly religious life that makes a female more likely to give birth. For instance, if they thought it was their religious duty to be fruitful and multiply, or if they saw something sacred or divine in conceiving and giving birth -- rather than view it as a threat to their material or career success -- then the more religious teenagers would have higher birth rates.

To answer this, I went to the General Social Survey, which has data on individuals. There is no variable for age at first birth, so I simply created a new variable which is the year of the first child's birth minus the year of the mother's birth. Unfortunately, this restricts the data to just one year, 1994. Still, that was before the teen pregnancy rate had really plummeted, so there should be enough variety among those who gave birth as teenagers for any patterns to show up. In order to get larger sample sizes, I grouped female respondents into four categories for age at first birth: teen mothers (9 to 19), young mothers (20 to 24), older mothers (25 to 29), and middle-aged mothers (30 to 39).

A lot of the questions about religion were not asked in 1994, but I managed to find three each for religious beliefs and religious practice. For beliefs, the questions measure whether she has a literal interpretation of the Bible, how fundamentalist she is (now and at age 16), and whether she supports or opposes a ban on prayer in public schools. For practice, the questions measure how often she attends religious services, how strong her affiliation is, and how often she prays. (See note [1] for how "rarely," "occasionally," and "frequently" are defined.)

First, let's look at how religious beliefs vary among women who gave birth first at different ages:


The pattern is stark: the earlier she had her first child, the stronger her religious beliefs, whether that means Biblical literalism, fundamentalism (now as well as at age 16), or opposing a ban on prayer in public schools.

Now let's look at how religious practice varies:




Here the story is a bit different. Teen mothers have lowest religious attendance, although young mothers have the greatest, while older and middle-aged mothers are in between. Also, teen mothers are tied with middle-aged mothers for lowest religious affiliation, whereas the young and older mothers have more strongly affiliated women. The pattern for prayer is the same as for attendance: teen mothers pray the least often, while young mothers pray the most, with the older and middle-aged mothers in between.

Putting these two sets of results together, we see that both of the plausible explanations for the state-level pattern show up at the individual level. Teen mothers are more delinquent in their religious practice, which supports the view that they have some basic wild-child personality that influences their attitudes toward giving birth and going to church. However, we know it cannot be some underlying antipathy toward religion that causes them to miss church or prayer because they are actually the most likely to hold fundamentalist or literalist beliefs. That supports the view that there's something about having a strong personal religious conviction that gives them a more favorable view of conceiving and giving birth.

Thus, the overall profile of a teen mother is a girl who is passionate enough in her religious beliefs that she sees something wonderful in giving birth, even at such a young age, but whose lower degree of conscientiousness keeps her from performing the institutional rituals as often as she should. Not being so well integrated into the institution, she doesn't feel whatever dampening effects the institution may have exerted through peer pressure (for lack of a better term). Indeed, if you've ever seen one of those teen mother episodes of Maury Povich, this portrait should be eerily familiar -- a misfit who isn't going to change her behavior just to lessen the authorities' social disapproval (whether her parents, Maury, or the jury in the audience), but who finds fulfillment in her private faith and in the ineffable bond between her and her child.

[1] For attendance, "rarely" is never, less than once a year, or once a year; "occasionally" is several times a year, once a month, or 2-3 times a month; and "frequently" is nearly every week, every week, or more than once a week. For prayer, "rarely" is less than once a week or never; "occasionally" is several times or once a week; and "frequently" is once or several times a day.

GSS variables used: sex, kdyrbrn1, cohort, bible, fund, fund16, prayer, attend, reliten, pray.

Brief: Do Asians consume boat loads of carbohydrates?

One thing that confuses many people about the value of low-carbohydrate diets is the presence of rice as a staple in East Asian diets -- if they eat so much rice, why aren't they as obese as we are? The key is that empty (or digestible) carbohydrates all have roughly the same effect -- to be converted into glucose, and thus raise our blood sugar and therefore our insulin levels over the long term.

Insulin is the primary hormone responsible for storing fat in fat cells, while just about every other hormone serves to break fat out of fat cells to be burned as fuel. Just think of when you get an adrenaline rush that prepares you for fight or flight -- you need to get lots of energy now, so get those fatty acids out of the fat cells. Chronically high insulin levels will therefore lead to weight gain, as well as extreme difficulty in losing weight if you go on some kind of diet and exercise program. Thus, it doesn't really matter that Asians consume more rice than we do. What we need is a total count of carbohydrates.

I went to NationMaster and checked per capita grain consumption for various countries, and their data come from the USDA. I'm sure there is more detailed information on the USDA website, but this is just a brief post. They include 6 food grains (corn, oats, rice, rye, sorghum, and wheat) and barley, which I take to refer to beer consumption. The lists are of the top 15 (roughly), and this list varies by grain, although some countries do show up across the board. All units are thousand metric tons per million population.

I've made two tables below, one with whatever data were available, and another where I replaced missing values with the minimum value to be conservative. (If a country didn't make it into the top 15, the greatest its value could be is the minimum of the top 15.) The ranking is essentially the same either way, though the bar chart below reflects the table with imputed values and leaves out barley (again the ranking doesn't really change, as you can see from the tables). I ignored a country if it didn't show up in at least one of the big three categories -- corn, rice, or wheat -- and retained those that showed up in many categories. Here are the results:

	barley	corn	oats	rice	rye	sorghum	wheat	sum	w/o barley
min	3.00	11.66	0.46	13.13	0.00	1.91	47.40
India		11.66		78.92		7.41	63.87	161.86	161.86
Indonesia		31.82		152.70				184.52	184.52
South Africa		196.19		15.22				211.41	211.41
Iran	32.00			45.58			194.07	271.64	239.64
Japan	13.00	125.57		67.95	2.35	11.77	47.40	268.05	255.05
China	3.00	98.06	0.46	103.34	0.00	1.91	80.00	286.78	283.78
South Korea		196.75		103.12	1.03			300.90	300.90
Brazil		198.80	1.85	43.52		5.91	53.46	303.55	303.55
Mexico	8.00	241.99	1.41			88.51		339.91	331.91
Russia	122.00		41.84		42.88		247.53	454.24	332.24
Egypt		141.92		42.58		9.68	163.86	358.04	358.04
Australia	149.00		54.75			84.62	308.61	596.98	447.98
Hungary		459.68	9.99					469.67	469.67
Canada	293.00	338.36	57.00		5.33		234.72	928.42	635.42
United States	19.00	700.02	11.57	13.13		18.04	112.27	874.03	855.03

	barley	corn	oats	rice	rye	sorghum	wheat	sum	w/o barley
min	3.00	11.66	0.46	13.13	0.00	1.91	47.40
India	3.00	11.66	0.46	78.92	0.00	7.41	63.87	165.32	162.32
Indonesia	3.00	31.82	0.46	152.70	0.00	1.91	47.40	237.30	234.30
Iran	32.00	11.66	0.46	45.58	0.00	1.91	194.07	285.68	253.68
Japan	13.00	125.57	0.46	67.95	2.35	11.77	47.40	268.51	255.51
South Africa	3.00	196.19	0.46	15.22	0.00	1.91	47.40	264.20	261.20
China	3.00	98.06	0.46	103.34	0.00	1.91	80.00	286.78	283.78
Brazil	3.00	198.80	1.85	43.52	0.00	5.91	53.46	306.56	303.56
South Korea	3.00	196.75	0.46	103.12	1.03	1.91	47.40	353.68	350.68
Egypt	3.00	141.92	0.46	42.58	0.00	9.68	163.86	361.50	358.50
Russia	122.00	11.66	41.84	13.13	42.88	1.91	247.53	480.95	358.95
Mexico	8.00	241.99	1.41	13.13	0.00	88.51	47.40	400.45	392.45
Australia	149.00	11.66	54.75	13.13	0.00	84.62	308.61	621.78	472.78
Hungary	3.00	459.68	9.99	13.13	0.00	1.91	47.40	535.12	532.12
Canada	293.00	338.36	57.00	13.13	5.33	1.91	234.72	943.46	650.46
United States	19.00	700.02	11.57	13.13	0.00	18.04	112.27	874.04	855.04

As you can see, despite scoring a bit higher than Western European countries on rice consumption, most East Asian countries don't consume "boat loads" of it. And in any case, looking at their overall grain consumption shows that they don't consume much of any of the other types either. Although China, Japan, and South Korea are developed nations, they blend right in with second and third-world countries in terms of grain consumption (in the poorer countries, this is likely all they eat, in contrast to the mounds of pork and fish that Northeast Asians enjoy). Western Europe and its off-shoots are clearly unusual in the amount of non-fiber carbohydrates that they consume, the US in particular.

It's true that grains are only one source of empty carbohydrates, but including others would only strengthen the pattern here, whether starches like the potato or straight-up sugar bombs like snack cakes, soda, and fruit juice. Even in Chinese restaurants geared toward American tastes, there is rarely any dessert offered, and that's also true for bakeries in Chinatowns. (You've never sampled such bland pastries.) Including sweets might distinguish some of the low-grain countries -- e.g., lots of syrupy sweets available in India compared to Japan -- but the chasm between East Asian and Western European populations would only widen.

This exercise drives home the importance of quantitative data rather than mere rankings. China indeed ranks far above the US in rice consumption, but it is "only" by 90 thousand metric tons per million population, and they don't outrank us in consumption of any other grain. By contrast, we outrank China in corn consumption -- but here it is by 600 thousand metric tons per million population, and we also lead them on the order of 10 thousand metric tons per million population for oats, sorghum, and wheat. Looking at these finer-grained data, maybe the longer lives and overall better health of East Asians, compared to other developed countries, isn't so surprising.