After Sputnik, the federal government funded in 1960 a vast survey of 15-year-olds' "aptitudes and achievements" called Project TALENT. Across the country in over 1300 high schools, five percent of all high school students, plus a bunch of dropouts they rounded up, took two dozen tests over four half-days.
They gave almost 400,000 students two dozen different tests. This was an era when psychometricians loved to give a wide variety of tests -- think of in The Right Stuff how the scientists loved to try out anything they could think of on the applicants for astronaut training. Since then, testing has tended to narrow as the dominance of the g-Factor has shown that two days worth of testing is redundant.
The overall scores would be a combination of aptitude and achievement, so not exactly like IQ, but no doubt reasonably well-correlated with IQ.
The data are available upon request.
I suspect that more Mexican-American 15-year-olds were enrolled in high school in California than in Texas in 1960, so this might be a biasing factor. Yet, both states were predominantly white in 1960.
One thing to keep in mind is that Project TALENT mostly measured students who were born during the Baby Bust of WWII rather than the famous Baby Boomers, the first of whom were 14 in 1960.
The fact that Texans scored about 1/10th of a standard deviation above Californians in 1960 suggests to me that the more famous accomplishments of Californians in science and technology (e.g., aeronautics) in the first half of the 20th Century were rather narrowly based demographically. In contrast, perhaps Texas's oil industry, which began in 1901 and sped up with the huge find in 1930, brought in to Texas a broad influx of technically skilled mechanics, engineers, and entrepreneurs, especially during the Depression. Anyway, it's interesting that as far back as 1960, there wasn't much evidence in Texas for the educational lassitude that afflicted much of the South outside of Virginia.
Here's something about Project TALENT that I posted in 2004:
IQs by State, 1960 -- You probably remember the notorious "Democratic states have higher IQs" hoax from last May. Well, here, thanks to Prof. Henry Harpending of the U. of Utah anthropology dept., might be the closest thing to a national sample of IQ scores ever: the Project Talent database of 366,000 9th-12th grade students. Unfortunately, it is 44 years years old. Nonetheless, it correlates reasonably with 2003 NAEP 8th grade achievement test scores (here are the 2003 scores). As you can see, in this list of kids' IQs back in 1960, of the top 10 smartest states, in 2000, Bush and Gore each won five. So, we're back to my original conclusion: red states and blue states are similar in average IQ, as are, on average, Republican and Democratic voters.
Some caveats: These IQ scores are set with the national mean of the 366,000 high school students equal to 100 and the standard deviation set to 15. But, keep in mind that we are only beginning to explore this huge database, so take everything with a grain of salt. [These scores are for all students across all races.]
New Hampshire 104.5
New Jersey 102.6
New York 102.5
North Dakota 101.8
New Mexico 98.9
Rhode Island 98.1
West Virginia 95.6
North Carolina 92.7
There weren't adequate sample sizes from Alaska, Washington DC, and South Carolina, and I excluded South Dakota because the result was too different from North Dakota. (I think something might be confused about both South Carolina and South Dakota -- I'll try to find out more.)
Harpending also looked at whites only data (unfortunately, the majority of participants don't have a race recorded) with the smartest whites (which I suspect is all that white liberals care about -- feeling smarter than white conservatives) were (in descending order): Connecticut, Montana, Nevada (I bet that's not true anymore!), Idaho, Illinois, Maryland, Massachusetts, Minnesota, Missouri, New Hampshire, New Jersey, New York, Oregon, and Virginia. The dumbest whites were in (in descending order): Georgia, Louisiana, Mississippi, North Carolina, Arkansas, Tennessee, West Virginia, and Kentucky.
The overall results by state in 1960 follow Daniel Patrick Moynihan's insight that the easiest way to improve social indicators in your state is to jack up your entire state, slide wheels under it, and haul it north up close to the Canadian border.