Saturday, October 24, 2009
The other day I saw a flier for a colloquium in my department that sounded kind of interesting, but I thought "It probably won't be worth it," and I ended up not going. After all, anyone with an internet connection can find a cyber-colloquium to participate in -- and drawn from a much wider range of topics (and so, one that's more likely to really grab your interest), whose participants are drawn from a much wider range of people (and so, where you're more likely to find experts on the topic -- although also more know-nothings who follow crowds for the attention), and whose lines of thought can extend for much longer than an hour or so without fatiguing the participants.
So, this is something like the Pavarotti Effect of greater global connectedness: local opera singers are going to go out of business because consumers would rather listen to a CD of Pavarotti. It's only after it becomes cheap to find the Pavarottis and distribute their work on a global scale that this type of "creative destruction" will happen. Similarly, if in order to get whatever colloquia gave them, academics migrated to email discussion groups or -- god help you -- even a blog, a far smaller number of speakers will be in demand. Why spend an hour of your time reading and commenting on the ideas of someone you see as a mediocre thinker when you could read and comment on someone you see as a superstar?
Sure, perceptions differ among the audience, so you could find two sustained online discussions that stood at opposite ends of an ideological spectrum -- say, biologists who want to see much more vs. much less fancy math enter the field. That will prevent one speaker from getting all the attention. But even here, there would be a small number of superstars within each camp, and most of the little guys who could've given a talk here or there before would not get their voices heard on the global stage. Just like the lousy local coffee shops that get displaced by Starbucks -- unlike the good locals that are robust to invasion -- they'd have to cater to a niche audience that preferred quirkiness over quality.
So the big losers would be the producers of lower-quality ideas, and the winners would be the producers of higher-quality ideas as well as just about all consumers. Academics wear both of these hats, but many online discussion participants might only sit in and comment rather than give talks themselves. It seems more or less like a no-brainer, but will things actually unfold as above? I still have some doubts.
The main assumption behind Schumpeter's notion of creative destruction is that the firms are competing and can either profit or get wiped out. If you find some fundamentally new and better way of doing something, you'll replace the old way, just as the car replaced the horse and buggy. If academic departments faced these pressures, the ones who made better decisions about whether to host colloquia or not would grow, while those who made poorer decisions would go under. But in general departments aren't going to go out of business -- no matter how low they may fall in prestige or intellectual output, relative to other departments, they'll still get funded by their university and other private and public sources. They have little incentive to ask whether it's a good use of money, time, and effort to host colloquia in general or even particular talks, and so these mostly pointless things can continue indefinitely.
Do the people involved with colloquia already realize how mostly pointless they are? I think so. If the department leaders perceived an expected net benefit, then attendance would be mandatory -- at least partial attendance, like attending a certain percent of all hosted during a semester. You'd be free to allocate your partial attendance however you wanted, just like you're free to choose your elective courses when you're getting your degrees -- but you'd still have to take something. The way things are now, it's as though the department head told its students, "We have several of these things called elective classes, and you're encouraged to take as few or as many as you want, but you don't actually have to." Not exactly a ringing endorsement.
You might counter that the department heads simply value making these choices entirely voluntary, rather than browbeat students and professors into attending. But again, mandatory courses and course loads contradict this in the case of students, and all manner of mandatory career enhancement activities contradict this in the case of professors (strangely, "faculty meetings" are rarely voluntary). Since they happily issue requirements elsewhere, it's hard to avoid the conclusion that even they don't see much point in sitting in on a colloquium. As they must know from first-hand experience, it's a better use of your time to join a discussion online or through email.
The fact that colloquia are voluntary gives hope that, even though many may persist in wasting their time, others will be freed up to more effectively communicate on some topic. Think of how dismal the intellectual output was before the printing press made setting down and ingesting ideas cheaper, and before strong modern states made postage routes safer and thus cheaper to transmit ideas. You could only feed at the idea-trough of whoever happened to be physically near you, and you could only get feedback on your own ideas from whoever was nearby. Even if you were at a "good school" for what you did, that couldn't have substituted for interacting with the cream of the crop from across the globe. Now, you're easily able to break free from local mediocrity -- hey, they probably see you the same way! -- and find much better relationships online.
Friday, July 17, 2009
It's nice to see a bad idea demolished. And that's what Greven, et al. do in "More than just IQ." Their subtitle tells most of the story:
School achievement is predicted by self-perceived abilities (SPAs)--but for genetic rather than environmental reasons.
So asking kids "Are you good at math and English?" is indeed a good way to find out who is good at math and English; and basic twin-study methods show that the answers to those questions are in fact genetically-driven, with heritability of 51% and family environment explaining 2%.
Another family environment channel shot down. The authors drive that fact home:
Despite the fact that not a single twin or adoption study has investigated the genetic and environmental etiologies of SPAs, researchers have cited environmental factors as a leading causal explanation for constructs related to SPAs, such as self-efficacy...and self-concept..... Moreover, one of the most established theories of SPAs assumes that the development of individual differences in SPAs is shaped primarily by parents' beliefs, expectations, attitudes, and behaviors...
Of course, the bulk of the academic literature will surely go right on assuming that self-construct is driven by shared environment: "Surely, you don't mean to imply that an entire field of research was a waste of time, do you?" And in the policy and non-profit worlds these results won't stop those "Book in Every Home" campaigns. Alas....
The genetic component of self-perceived abilities (SPA) is a good predictor of achivement, after you control for IQ.
Even after you control for IQ and self-perceived ability, there's still a big genetic residual--about as big as IQ's genetic channel: So there are big genetic drivers of school achievement that don't fit into the two simple boxes of IQ and SPA. Sounds like an opportunity for some productive data-mining....
The big genetic residual fits in with the fact that a person's income is vastly more heritable than can be explained by the IQ channel alone. There are more things in gene expression, Horatio, than are dreamt of in your WAIS-R.
Sunday, May 10, 2009
To test how sensitive Google Trends is to fundamental changes in the thing you're asking about, I decided to see if it could pick up the seasonality of fruit availability. Sure enough, it does. Just check blueberries or pomegranate: when the fruits are plentiful, people are very interested in them; outside the peak season, interest plummets. Interestingly, you see something very similar for how much people are searching Google for intellectual topics, which is an indicator of how long their interest lasts.
I noticed a funny cyclical pattern awhile back when I searched Google Trends for slavery. I had a hunch but filed it away. Now I've looked into it, and it's what I thought -- it tracks the school year, specifically when mid-term and final papers are due during the fall and spring semesters. There's sharp drop during Christmas vacation, and a steady low level during summer vacation. To show that this is true, you see the same pattern for postmodernism, Freud, Foucault, semiotics -- plus Darwin, evolutionary psychology, differential equations, and linear algebra.
That shows how long the average student, after exposure to some body of thought, retains interest in it over their lifetime -- about a day or so after the exam is done. And intellectual merit hardly seems to matter -- real stuff like differential equations doesn't seem any stickier than the snake oil of postmodernism. If you're an educator who's ever suffered from the delusion that you can inspire lasting interest in your subject, these graphs should wake you up. Sure, there's that one student whose eagerness for the subject is just a bit creepy (unless she's a cute girl, of course), but most of your students will treat your class like they do the movies they see in the theater -- or the Malcolm Gladwell books their parents read -- which provide brief fun but are forgotten a week or so later.
This more or less contradicts the proponents of higher ed for everyone, of a core curriculum, and of similar policies that are based on the assumption that students retain anything at all. After their Harvard undergrad educations, most alumni had no clue what causes the seasonal change in weather. (They tend to say that it's due to the elliptical orbit of Earth around the Sun -- summer when it's closest and winter when it's farthest away.) If they're just going to flush out the course's content once the semester is over, why make them take the course in the first place? Except for the school to get their money, and for the professor to keep his job through high enrollment.
"But higher ed is not just pre-professional training -- it's about cultivating the garden of their mind!" Well, if the average student were at all intellectually curious, maybe. But most aren't -- once their final paper is in, flusssshhh! To revisit the topic of the education bubble, most arts and humanities majors could cruise through undergrad in two years tops, unless they were dead set on becoming academics, in which case they'd really need to absorb a lot more information. But if you're majoring in history or English in order to go to law school, who cares if you only surveyed one period of English poetry, rather than from Beowulf to the Beats? Obvious exceptions are technical or professional majors, such as engineers needing to know calculus, statistics, etc., which might take them three years to complete.
The cold hard reality, shown by the Google Trends data above, is that just about all students are going to junk everything they ever learned in college once they're done with the course -- not even once they graduate. Therefore, having them schlump around all day in these throwaway courses only wastes their time, money, and energy, which could be spent producing stuff. Aside from signaling that they haven't gone braindead or really fucked up their work ethic after high school, a college degree doesn't mean much, unless it's a technical one. So, give them a year or two to prove this, and then get them out into the real world. They'll probably come out the other end of college with healthier livers to boot.
Tuesday, May 05, 2009
A simple but powerful way to determine whether or not there's a irrational bubble is to look for a lot of people who are participating in a trend who have no business doing so. For instance, a Mexican strawberry-picker making $15,000 a year who gets a $720,000 loan for a home. If these don't-belong-there people make up a larger and larger fraction of all who get loans, that strongly suggests that everyone is trying to get in on a speculative bubble -- and that the gatekeepers of the activity are increasingly debauching their entry standards to accommodate the losers.
One datum that suggests an irrational bubble in education is that a much larger fraction of the population is going to college now, and that not surprisingly the average IQ of college students has declined by about 2/3 s.d. -- admissions boards began to scrape deeper down into the sludgebucket of society.
How about looking even earlier? High school is compulsory, so we can't really use high school enrollment to judge whether there's a bubble or not. But what about the sub-group of high school that ostensibly is there to prepare college-bound students for college? That is up to the choice of students, perhaps being bullied by their parents. There is strong evidence even at this early stage of an irrational bubble.
What got me thinking about this was a recent NYT article on how teachers feel about the Advanced Placement program, which is based on a report from the Thomas B. Fordham Institute. The key item that popped out was the claim that participation in the AP program has exploded in recent years, and that this has made a fair fraction of teachers anxious about whether there are students there who shouldn't be. This sure smells like a bubble.
First, let's make sure that the AP program really is exploding as they say, and then we'll see if there's a rational basis for it or not. To measure participation in the AP program, I simply took the number of AP tests taken and divided it by the high school population size. (The AP data are here, and the high school pop data are here, Table A-1.) The AP data go back to 1988, while the high school pop data end in 2007, so I looked at the period from 1988 to 2007. Here are both the total number of AP tests taken and the per capita rate:
An exponential trend accounts for 99.8% of the year-to-year variation for the total number of tests taken, and 99.2% in the per capita case. So, clearly participation in the AP program has been exploding at least since 1988.
Now, is there a sound basis for this increase -- like, maybe kids these days are just getting exponentially smarter? Without looking at the data, we know this is wrong since the main determinant of doing well in AP classes is IQ, and that is influenced mostly by genes and unpredictable aspects of the environment, which haven't been changing so rapidly from one year to the next.
Turning to data on how well 17 year-olds are doing academically, let's look at some tables from the 2007 version of the Digest of Education Statistics (all under Chapter 2, and then Educational Achievement). Table 112 shows that on the National Assessment of Educational Progress, the average reading score for 17 y.o.s did not change from 1971 to 2004. Table 115 shows that the percent of 17 y.o. students who are at the 300 level or above in reading did not change from 1971 to 2004. Tables 125 and 126 show the same lack of change for math skills tested by the NAEP. Table 135 shows that the average Critical Reading score on the SAT did not change from 1988 onward -- indeed, it was steady back to about 1976, and had been declining before then. There was a modest uptick in Math scores (15 points, or 0.15 s.d.). The Critical Reading or Verbal score is more highly g-loaded than the Math score for the SAT, or is a better measure of IQ, which means the apparent uptick in Math scores may not mean as much as we'd think.
Taken together, these data show that the academic fundamentals of high schoolers has not changed since the 1970s. If there has been no upswing at all in the fundamentals -- let alone an exponential one -- then the explosion of the AP program is accounted for completely by irrational factors. It seems just like the housing bubble -- the size of deserving borrowers didn't explode, so the surge in borrowing must have been due to a bunch of undeserving people pouring into the building, namely low-income people. Here are two graphs showing that this happened in the AP program too:
The first shows the distribution of AP scores, where 5 is greatest. You can check the numbers for yourself in the previous link to the AP data, but there has been no change in the percent of all tests that received a score of 4 or 5 -- there have not been more and more smarties piling into AP classrooms, at least not since 1988. Therefore, everyone who deserved to be there was already there. However, the percent of all tests receiving a score of 1 -- telling the student, "why did you even bother?" -- has doubled from 10% to 21%. Those receiving a 2 shrunk a tiny amount, from about 23% to 21%. But those receiving a 3 declined from about 32% to 24%. This means that, unlike for smarties, more and more dummies have been allowed into the AP program.
This is reflected in the change in the mean and standard deviation of test scores: keeping the smarties fixed while adding a lot more dummies will drag down the mean and increase the heterogeneity or variance. That's analogous to the housing bubble causing a decline in the mean creditworthiness of the population of borrowers, and an increase in their heterogeneity, as both the sound and the unsound begin to rub shoulders in loan offices. And just as lenders increasingly cheapened their standards by not requiring down payments or proof of income, so high school teachers and administrators have allowed increasingly ill-prepared -- stupid -- students into the AP program.
In sum, there is very strong evidence from AP tests for a speculative bubble in education. Most of what I've read on whether or not such a bubble exists has focused on college -- soaring tuition, more and therefore dumber students, and so on. These data, though, show that the mania extends even to high school, not just higher ed. For at least the past five years, there have been many news stories about competitive admission to pre-school, so perhaps someone could dig up some numbers to show an exponential increase there too that can't be rationalized by a change in fundamentals. In any case, it's clear that this bubble is much more general than the college data suggest.
Curiously, the phrase "education bubble" has not appeared at all in the NYT, although it has appeared many times in the blogs that the newspaper hosts. Googling the phrase gets 39,000 hits. Rises and falls in tuition get plenty of coverage, but that doesn't show that the reporters are aware of the irrational bubble -- they just think it's unfair, that college should be cheaper so that more can attend. But just as no one was allowed to say that most low-income borrowers were undeserving of home loans since they were disproportionately black and Hispanic, so we aren't allowed to say that a lot of college students are nowhere near being "college material" -- that would violate the "demotic life and times," as Jacques Barzun has dubbed the zeitgeist from roughly the 1960s until today. We cripple our minds by imbibing political correctness.
The bursting of the education bubble may be decades away -- it sure has been going on for awhile, so its period may be much longer than that of the housing or stock market bubbles. Let's just hope that when it happens, it will turn out that hedge funds and investment banks won't have exposed themselves to all of this silliness, and that we won't be plunged into another multi-year recession.
Monday, September 22, 2008
Recently Charles Murray has promoted the idea that too many people are seeking 4 year degrees: "Let's stop this business of the B.A., this meaningless credential". Last year he wrote in the Wall Street Journal:
If you want to do well [in college], you should have an IQ of 115 or higher. Put another way, it makes sense for only about 15% of the population, 25% if one stretches it, to get a college education. And yet more than ... 40% of all persons in their late teens are trying to go to a four-year college--enough people to absorb everyone down through an IQ of 104.
Several months ago, the Inductivist found this to be a canny estimate: in the 1960s the average college graduate had an IQ very close to 115, and today the average college graduate has an IQ of 105.
But what does this mean for the individual? Murray suggests that college debt, lack of relevant job training, and years of lost workforce wages and experience await those below the 85th percentile:
They are in college to improve their chances of making a good living ... and would do better in vocational training ... two-year colleges ... [are] about right for learning many technical specialties, while four years is unnecessarily long ... Finding a good lawyer or physician is easy. Finding a good carpenter, painter, electrician, plumber, glazier, mason--the list goes on and on--is difficult, and it is a seller's market. Journeymen craftsmen routinely make incomes in the top half of the income distribution while master craftsmen can make six figures.
I find the thinking here plausible, and these seem like testable enough ideas. Luckily, all the relevant variables are included in the General Social Survey.
It's graph day on gnxp. The x axis in the figure below represents the number of correct answers on the 10 question WORDSUM mini IQ test included in the GSS. The y axis represents the respondent's income in constant dollars. The colored lines represent five educational categories, and one occupational category. Moving left to right we see the average income of people in each category as their IQ score increases from 0-10 correct answers. 'Junior college' represents the two-year vocational degree Murray references. And 'Craft and Trade Workers' covers over 50 skilled trade categories like electrician, mason, plumber, carpenter, and mechanic, coded by the survey.
The first observation here is that educational degrees, whether they confer skills or credentials, are more important to income than IQ when minimum thresholds are met. Trade workers, and 2 and 4-year college graduates are not significantly represented in the lowest three IQ categories. Graduate holders have an even higher minimum IQ. Second, income rises within 5 of the 6 categories as IQ increases. Higher IQ generates the biggest pay-off differences between those with advanced degrees, which is consistent with IQ increasing in importance as jobs become more complex. Third, merely earning a Bachelor's degree is a golden ticket. People with average and below average IQs are getting just as much of a financial return out of their 4-year degree as those above the 85th percentile. This suggests many more people of marginal ability should be seeking a Bachelor's degree, not less. Fourth, the two lines for junior college and trade occupations overlap substantially, as we would expect if most people in trade occupations went to trade school. Fifth, and most directly related to Murray's argument, people with 4-year degrees earn much more than people with 2-year degrees and trade jobs at every level of IQ. Average IQ people will get a much, much larger monetary reward from completing a 4 year school than a 2 year school. So the BA is far from being a "meaningless credential" when it comes to "chances of making a good living".
It's possible people with average IQs who complete college are exceptional in other ways. But there is no other empirical evidence that vocational school is better at generating income for those <85th percentile.
Also, secular trends could distort data in the first graph, which combines all survey data from 1972-2006. So the second graph below represents only people who were 35 and older and surveyed between 2000-2006. Fortunately, the results are not too different from the first graph. The IQ categories are condensed and transformed, and we see that 96 is about the minimum to complete 2 and 4 year college, and 111 the minimum for graduate degrees. Again we find that IQ shows no relationship to income for those with a BA, and, in fact, those with lower IQs might profit the most. For those without advanced degrees, people who are moderately above and moderately below average intelligence might earn the most (this balance might be because other socially valued personality traits, like masculinity, are inversely associated with IQ).
So, while I have yet to read Real Education -- which may address these issues -- it would appear that Murray is mistaken in some of his crucial premises.
Still undetermined is if people with 4 year degrees earn a lot more money because they actually acquire important skills, or if inefficient laws/taboos against employee IQ testing, sustain a comically messy and tragically expensive employment screening method. If the latter was true Murray could still be partially correct: 4 year college could be worthless for the <85th percentile, if employers began to use 20 minutes of psychometric testing, instead of 4 year degrees, as their screening filter.
But, ceteris paribus, college is still the best pay-off.
Tuesday, July 15, 2008
In the post below, Colder climates favor civilization even among Whites alone, I made a few comments about possible differences between Germans in Illinois and Germans in Texas, based on nothing much more than a hunch. I trust my hunches, but there's no reason you should, so I decided to see if there was anything here in regards to my assumption about interregional differences in intelligence and how they might track across ethnic groups. So of course I went to the GSS website, and checked the mean WORDSUM scores of various white ethnic groups broken down by region. I specifically focused on whites who stated that their ancestors were from England & Wales, Germany and Ireland. My reasoning is that these are three groups with very large N's within the GSS sample and they are well represented across the regions in absolute numbers. My main motivation was see if the differences across regions were similar for all three groups. Here are the states for each region (the Census made up these categories):
New England - Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut
Middle Atlantic - New York, New Jersey, Pennsylvania
East North Central - Ohio, Indiana, Illinois, Michigan, Wisconsin
West North Central - Minnesota, Iowa, Missouri, North Dakota, South Dakota, Nebraska, Kansas
South Atlantic - Delaware, Maryland, District of Columbia, Virginia, West Virginia, North Carolina, South Carolina, Georgia, Florida
East South Central - Kentucky, Tennessee, Alabama, Mississippi
West South Central - Arkansas, Louisiana, Oklahoma, Texas
Mountain - Montana, Idaho, Wyoming, Colorado, New Mexico, Arizona, Utah, Nevada
Pacific - Washington, Imbler, California, Alaska, Hawaii
Obviously the breakdown isn't ideal. I think Delaware and Maryland arguably should be Mid-Atlantic. I also believe that Wisconsin is more plausibly in the West North Central than Missouri or Kansas is. But those are the regional breakdowns and I can't do anything about them.
So, WORDSUM is a vocabulary test on a 0-10 scale. For the whole GSS sample the mean was 6.00, with 1 standard deviation being 2.16. Below is a chart which shows the relationship between WORDSUM scores (Y axis) for various regions (X axis) for each of the three ethnic groups:
The tables below are pretty self-explanatory. At the top you see the mean WORDSUM scores for each ethnic group for each region. I put the N's in there as well so you can see that the sample sizes were pretty big. Note that there is more interregional variation within an ethnic group than there is interethnic variation within a region (the standard deviation across the columns is 50% bigger than across the rows). Just to be clear, I also included some tables which show the differences in WORDSUM mean scores between the regions like so: (row - column) = value.
Last year I had a crazy idea about how winged insects might influence civilization. I only pointed to winged insects as an exemplar, not to suggest a "Mosquito Theory of History" or something stupid and sexy like that. The reasoning is simple: insects are more likely to be winged in certain climates, and that means more effective vectors of disease in such environments; and a greater disease burden makes you dumber, more tired, and more irritable, which stunts the growth of civilization.  A qualitative follow-up post looked at where civilizations have ever appeared, and in what climate types they existed.
Well, now I've done some quantitative work, and it turns out that I was right. One critique against an international study is that natural selection may have adapted people to be more or less civilized in different environments, so that the only influence of climate is as a selection pressure for genetic change. There are at least two such studies already out there: one by Templer & Arikawa (2006) and another by Vanhanen (2004). I'm arguing that it matters even when people start out pretty much the same genetically, so I will look just at the US. It varies enough in climate and degree of civilization that any correlation should jump out.
In particular, I will look at the correlation, on the level of states, between average annual temperature and the average IQ of Whites, post-secondary degrees awarded to Whites per capita, and the percent of the White population that's imprisoned. I only look at Whites in order to avoid the confound of climate with racial composition (for example, the cold Mountain states are heavily White, while Blacks make up a larger fraction in the hot Southeast).
The reason I look at basic measures like IQ or being in jail, as opposed to the loftier things we associate with civilization, is that smarts is the key determinant of propelling the institutions of civilization forward, while crime gives us a good rough idea of how barbaric we are on a personal level. I'm sure that governments can improve or screw things up too, but it's the raw cognitive and behavioral materials that matter most, as Lynn and Varhanen show in IQ and the Wealth of Nations (see all GNXP posts on this topic). Moreover, studies of representative samples of the population always show a strong influence of IQ on how cultured a person is. See, for example, a National Endowment for the Arts report on the demographics of arts attendees (PDF p. 19), which shows that attendance increases nearly monotonically by education level.
As you can see, hotter average temperature is associated with lower White IQs, fewer degrees being awarded to Whites per capita, and a higher percentage of the White population being imprisoned. The relationship looks pretty linear in each case, and the data are on an interval scale, so we check the Pearson correlation coefficient: between White IQ and temperature, it is -0.48 (p = 0.0005, two-tailed); between degrees to Whites and temperature, it is -0.57 (p = 0.00002, two-tailed); and between percent of Whites in jail and temperature, it is +.40 (p = 0.005, two-tailed). Even conservatively correcting for three independent hypotheses still leaves all results significant (and IQ and getting a college degree are not even independent). At any rate, average temperature accounts for 23%, 32%, and 16% of the variance in White IQ, degrees to Whites, and percent of Whites in jail, respectively -- pretty damn good for social science. 
I took the average annual temperature for each of the 48 continental states (Alaska and Hawaii were not included in the source, so I left them out). Next, I used Audacious Epigone's estimates of White IQ by state, which are based on NAEP data from 8th grade math and science test scores (read about his methods here). I turned to Statemaster.com for the per capita number of post-secondary degrees awarded to Whites. For the number of Whites in prison per 100K Whites in the state's population, I used the data from 1997 in a study by the National Center on Institutions and Alternatives (PDF here), which separates non-Hispanic Whites from Hispanics, unlike most crime data from government agencies. 
Here, correlation probably is causation, as climate precedes the other three variables in causality, and again because these are unlikely to be genetic differences that reflect adaptation to different environments -- one of the few cases where natural selection "has not had enough time."
An objection is that the differences could reflect a "brain drain," whereby smart people flock to colder states, and their smart children boost the state's NAEP scores. Even in this case, where climate does not cause group differences in IQ, it still confirms the hypothesis that colder climates favor civilization -- why else would smarties flock there? But I doubt this anyway, since Montana, Wyoming, and North and South Dakota are not exactly fonts of civilization that smarties pour into, yet they have White IQs on par with the highly developed New York City metro area.
If it is causation, as seems likely, the mechanism could be anything. Pathogen load is surely part of it, hence the fields of study called "tropical disease" and "tropical medicine." Also, you might sweat too much in hotter environments, bringing you closer to dehydration. As mild as these effects may seem, when accumulated over the course of development, they could result in your body spending more resources on bodily maintenance than on luxury items like IQ and toil. Heat could also just make you more fatigued -- that wouldn't affect IQ, but it would affect your work ethic, making you less likely to complete college and more likely to pursue quick fixes like crime to get what you want.
The correlation is stronger for getting a college degree than performance on 8th grade math and science tests, and that could be because college work is more g-loaded, because it also taps into work ethic aside from IQ, and because out-of-staters show up in the college figures but not the 8th grade figures. As tough as the environment may seem to natives, it must seem unbearable to college students raised in a different climate.
To the best of my knowledge, as the saying goes, this is the first demonstration of an association between climate type and IQ, civilization-related achievement, and crime, even among a population that's pretty homogenous genetically (for the traits of interest, at least). Even what genetic diversity there is among Whites would underestimate the effect -- Whites adapted to hotter environments, such as Italians and Greeks, are far more concentrated in the colder states within the US. To put the final nail in the coffin, though, you'd want to look at babies of Whites who are adopted into White families in a state of noticeably different temperature than that of the biological parents.
Still, it seems pretty unavoidable: hotter environments are less conducive to civilization, at least for Whites, and not just in extreme cases like the failed attempt to colonize sub-Saharan Africa. Civilization may have started in hot areas, but that was then. It apparently flourishes much more in colder climates. Just as we provide iodine in table salt to prevent a nutrient deficiency from lowering IQ, it might be just as well to encourage people to settle colder areas.
It's not like they'd be abandoning civilization -- just the opposite. They could take their accents, music, and whatever else with them, but they would not suffer the environmental insults that lower their group's IQ, lower their ability to get a college degree, and make them more likely to commit crime. Fortunately for them -- and unfortunately for current residents -- the Mountain states have incredibly low population densities and could absorb some Whites from hotter states. That would certainly burden the locals for a generation, but again since lower White IQ in the Southeast is probably due to largely treatable environmental causes, it won't take long for them to contribute as citizens on the same level as the locals.
 Underlying this is likely a tendency for all sorts of things to be more migratory in such environments -- winged insects were chosen because there's lots of solid data to illustrate the point. Basically, environments that are highly unstable favor migratory features since your environment may go from good to bad from one day to the next, or from one spot to the next -- and being able to quickly move on to greener pastures will be well worth it. When environmental quality does not change much in space or time, then the expensive wings (or whatever) will not pay off.
 If you don't have statistical software, you can do a lot for free on Wessa.net, including correlation.
 Although I didn't run a test of normality on the distributions for temperature, iq, degrees, or crime, I did check the skewness of all, and only crime was significantly skewed: for crime, skewness is +2.1 standard errors of skewness (SES); for temperature, +1.24 SES; for degrees, +0.35 SES; and for IQ, -1.51 SES.
Addendum from Razib: I put up a related post at my other weblog.
Sunday, June 08, 2008
Readers in the UK may have seen recent press reports about a controversial article by Bruce Charlton, an evolutionary psychologist at the University of Newcastle. Charlton points out that average IQ differs in different social or occupational classes (e.g. doctors or lawyers have higher IQ than casual labourers), and that in consequence, if IQ is relevant to higher education, we would expect participation in higher education also to vary according to class. Predictably, ritual curses and denunciations have rained down on Charlton's head.
I wanted to read Charlton's article, but found it more difficult to find than I expected. The press reports suggested that it appeared in Times Higher Education (the former Times Higher Educational Supplement), but on tracking down the relevant issue I found a report about Charlton's article, but not the article itself. The article is however available as a Word document on the THE website. (See the right margin of the webpage here). I make a few comments of my own below the fold.
Probably most readers will agree with the broad thrust of Charlton's article, but there may be a confusion between the IQ of parents and that of their offspring. Charlton seems (as far as I can see) to assume that the mean IQ of applicants to higher education is the same as that of adults in their parental social class. This is not generally the case. The correlation between the IQ of parents and offspring is only about .5, which implies considerable regression towards the mean. The IQ of the offspring of parents with IQ of, say, 130 will on average be lower than 130, while that of parents with IQ of, say, 85 will be higher than 85. There is a difference of up to 40 IQ points between adults in the highest and lowest occupational classes (depending on the classification used), but only about 15 to 20 points between children from those classes. (For some data see Anastasi, chapter 15.) The difference in average IQ between social classes is kept roughly constant by social mobility, as the dimmer children of the higher classes tend to fall in the social scale and the brighter children of the lower classes tend to rise. (See Mackintosh, pp. 144-8). This does not invalidate the main point of Charlton's article, but it may affect some of his specific quantitative comparisons.
I think it may also be unfortunate that Charlton describes the present system of entry to higher education as 'meritocratic'. Entry to publicly funded higher education should not be seen (primarily) as a reward for past achievement, or a badge of 'merit'. The proper criterion for entry decisions is how far an individual can benefit from the course of study concerned. In general, individuals who have struggled at school are unlikely to benefit from higher education at all. If applications for a particular course of study exceed the number of places available, those applicants should be chosen who will benefit most from the use of scarce resources. It is the scarcity of high quality resources that justifies the selectivity of the 'elite' universities. One would not expect an haute couture seamstress to stitch potato sacks, and one should not expect a Fellow of Trinity College Cambridge to teach mediocre students. Such students would not derive the greatest benefit from the teaching, and indeed the teaching would probably not be the best available for such students.
I am assuming in all this that higher education is by definition at a more advanced and demanding level than that of ordinary school education. It is not to be confused with post-school education at a similar level to that of schools, such as is provided by Further Education Colleges in Britain. This may be admirable in its own way, but it is not higher education.
Anne Anastasi: Differential Psychology, 3rd edn., 1958
N. J. Mackintosh: IQ and Human Intelligence, 1998
Sunday, February 11, 2007
Wherever the abilities involved are sufficiently distinct--and that is in the great majority of cases--our tetrad equation is satisfied with surprising exactitude, so that here each ability must be divisible into g and s. The letter g becomes, in this manner, a name for the factor--whatever it may be--that is common to mental tests of such a description. This is the very definition of g. (Spearman, 2005, p. 161)
General intelligence (g) has been one of the most, if not the most, aggressively studied constructs in psychology. Type the search string "general intelligence" in PsycInfo and you will return over 2000 entries, and a similar search in Pubmed pulls up over 400. If you broaden the term to just "intelligence", the respective number of entries are 65405 and 37166. While not all of the results focus on g , (e.g., AI, "social intelligence"), a large portion of them do, and the prospect of meandering your way through can be intimidating. Fortunately, the overall literature is consistent and, at least for me, highly engaging.
The study of g can be bifurcated into two distinct areas: vertical and horizontal g . Vertical g is the domain that studies g's biological relationships. It is the area that is going to eventually assimilate enough data and literature to elucidate, unquestionably, the causal mechanisms of g . From this field of study, we know that g is correlated with a variety of neural mechanisms, such at glucose metabolism (Haier, 2003), cortical development (Shaw et al., 2006), and biochemical activity (Jung et al., 2005). We know that g is highly heritable, both when measured psychometrically (Plomin & Spinath, 2002) or chronometrically (Beaujean, 2005). We know that g decreases with inbreeding (Jensen, 1983) and increases with hybrid vigor (Nagoshi & Johnson, 1986). As genome scanning becomingmore popular, we are now even beginning to see some specific genes that are implicated g.
As interesting as vertical g is, however, this entry is going to instead focus in the horizontal aspects of g . That is, how does g play out into "everyday life." Specifically, we will look three different, although related, areas: education, occupation, and general life outcomes. The reasons for doing so are twofold: (a) the more the science of horizontal g is positively promulgated, then, perhaps, the more likely people are to support the needed research into vertical g and (b) even though this area of research has been around for over a century (e.g., Galton, 1869), there are still new, important findings.
Before delving into horizontal g, however, it would behoove us to delineate a mechanism by which g could influence education, occupation, and general life outcomes.For our purposes, that mechanism is information processing. Generally defined, information processing is the pathway and mechanisms by which stimuli are perceived, attended to, retrieved, and/or used to solve problems and/or cope with exigencies in the environment (Jensen, 1998a). The cognitive psychology literature is chalked full of the nuances of the various information-processing theorists, the specifics are which cannot be delineated here (an easy-to-read intro: Ormrod, 2004). Yet, within all these theories lies the idea that people respond to stimuli in a way that involves many mechanisms (e.g., sensory register, primary memory)and a variety of neurological regions (e.g., hippocampus, amygdala, mammillary bodies). The consequence? There is ample room for individual differences in the speed and efficiency in which information is processed.
From another perspective (e.g., Kline, 1998), information is processed in irreducibly small pieces (often called bits) and the time it takes to process those bits is the BIP, the Basic period of Information Processing. Now, the time it takes Johnny to process the fact that the only integer between 2 and 4 is 3 is going to be different than the time it takes Jane. Multiply those differences by the number of people processing the fact, and voila! individual differences.
This is probably the area most replete with data and, unsurprisingly, the g-educational achievement relationship is strong. In fact, although it differs by grade level (with it decreasing as grade level increases), most of the non-random variance in scholastic performance is accounted for by g (Thorndike, 1984). Jensen (1989, 1998b) writes that this is so due to the fact that "school learning" is, itself, quite g -loaded. Of course, there are those who write that g is just a product of education (e.g., Ceci, 1991; for a review of others, see Gottfredson, 1986), or, perhaps more egregious, that g and educational achievement are just products of the tests designed to measure them (for review and rebuttal, see Jensen, 1984). But these arguments quickly dissipate when looking at the evidence.
For example, in the latest issue of Intelligence, there were two longitudinal studies (Deary, Strand, Smith, & Fernandes, 2007; Watkins, Lei, & Canivez, 2007) that showed a strong IQ --> Educational Achievement relationship (approx. 70 from Deary), but reverse (i.e., EA --> IQ) was not there (from the Watkins study). Further evidence comes from the two major "We can improve you Education by improving your IQ" projects: Head Start and the Abecedarian Study. With regard to the former, Head Start just does not produce long-term IQ gains and, hence, does not produce long-term academic gains (Caruso, Taylor, & Detterman, 1982; Holden, 1990; Kreisman, 2003). With regard to the latter, while there has been acrimonious debate, the overall conclusion is that, like Head Start, the initial IQ gains do not last, giving even more evidence that educational achievement cannot be raised independently of g (Spitz, 1986, 1992, 1993b, 1993a).
Yet another line for arguing against the prominence of g in education is the idea that there are other traits that are just as necessary for academic success, such as motivation, personality, etc. To risk sounding like to broken record, the data shows that these traits are not nearly as potent predictors as g in predicting academic outcomes. For example, Gagne and St. Pere (2002) gives us reason to believe that motivation might just be an impotent variable in predicting academic achievement. Likewise, Laidra, Pullmann, and Allik (2007) have shown that while personality factors contribute some to the variance in educational achievement, they are dwarfed in comparison to the contribution of g.
There are many theories as to how g and occupational outcomes relate (see Gottfredson, 1986), but the one that is most supported by data is best explicated by Frank Schmidt and John Hunter
[g] predicts both the occupational level attained by individual and their performance within their chosen occupation. [g] correlates above .50 with later occupational level, performance in job training programs, and performance on the job. Relationships this large are rare in psychological literature and are considered "large" . . . weighted combinations of specific aptitudes (e.g., verbal, spatial, or quantitative aptitude) tailored to individual jobs do not predict job performance better than [g] measures alone, thus disconfirming the specific aptitude theory. It has been proposed that job experience is a better predictor of job performance than [g], but the research findings . . . support the opposite conclusion. . . . Nearly 100 years ago Spearman (1904) proposed that the construct of [g] is central to human affairs. The research . . . supports his proposal in the world of work, an area of life critical to individuals, organizations, and the economy as a whole.(Schmidt & Hunter, 2004, p.171; cf.Schmidt & Hunter, 1998)
One could argue that, given the high g -education relationship, that the g-occupation relationship is just a natural outgrowth.That is, once education is controlled, the g-occupation relationship significantly shrinks. But to make that argument, one would have to have a Sternberg-like approach to intelligence (Sternberg & Wagner, 1993). That is, that the cognitive skills needed for a successful education are somehow vastly different than those needed for everyday life. The data, however, indicate that the same generative process that tends to makes one successful in the educational arena is also the mechanism that tends to make one successful in the occupational arena: g (Kuncel, Hezlett, & Ones, 2004). This is not to say that other things are not important in occupational or educational outcomes; but, as with education, they are not nearly as potent predictors (Gottfredson, 2002).
Over the last decade or so, an area that has become of more interest to the intelligence community is the influence of g on general life outcomes. That is, beyond educational and occupational outcomes, does g contribute to life success? The answer here, too, seems to be a resounding yes.
IQ scores [a proxy for g] predict a wider range of important social outcomes and they correlate with more personal attributes than perhaps any other psychological trait. The ubiquity and often-considerable size of g's correlations across life's various domains suggest g truly is important in negotiating the corridors of daily life. (Gottfredson, 2003, p. 326)
But how does g relate to general life outcomes? Believe it or not, it appears that the same information-processing mechanisms that are so potent for educational and occupational outcomes also play a role in day-to-day life (Gottfredson & Deary, 2004). Gottfredson (2003, 2004b) elaborates this mechanism as follows: Life is is made up of many tasks with a wide array of complexity (Gordon, 1997). In the US and most Western nations, society is "free enough" for competence (read: g ) to make a substantial difference in who succeeds in life. As those who have "higher g" are more able to tackle the day-to-day activities of life successfully with less exerted effort, they are able to progress in life with fewer impediments (e.g., untreated illness, accidents; Gottfredson, 2004a), thus allowing them to (a) have more resources to successfully compete and (b) be able to use their resources more efficiently. This then not only allows for a higher probability of achieving satisfying life outcomes (e.g., adequate income, occupational autonomy), but also allows for a lower probability of being involved with unsatisfying life outcomes (e.g., having children without means to support them, crime/delinquency) (cf. Ellis & Walsh, 2003; Herrnstein & Murray, 1996)
Given the ubiquity of g in fostering success in many life outcomes from education achievement to occupational success, from health outcomes to criminal recidivism, social science in general and psychological science in particular would be remiss to "pretend it doesn't matter" (Gottfredson, 2000). Rather, if these fields want to strengthen their scientific integrity and acumen, they should do exact opposite. That is, bring the large, cumulative database on g and its influence on life outcomes to the forefront of a wide array of research agendas so that this corpus of data can serve as the strong underlying foundation of a generation of new investigations on g's life implications. While this line of investigation may never get to the underlying (vertical) mechanisms by which g operates, it can help foster the acceptance of doing such research and pave the way for its societal implications, whatever they may be.
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