April 27, 2009

Truck driving and cognitive skills

Years ago, a reader who owned a trucking firm asked me if IQ testing could help his firm pick truck drivers who wouldn't quit on them, wouldn't get lost, and wouldn't get into costly accidents. The U.S. military often assigns low scorers on the AFQT to truck driving duties, but, keep in mind, virtually the lowest scorers allowed to enlist from 1992 thru 2004 were 92 IQs, who aren't stupid by any means. Truck driving involves a fair degree of cognitive demands, but not as much as, say, driving a tank, so the military figures it can get away with putting its 2 digit IQs into truck driver spots.

It sounded like an interesting project, but I never got around to it, and have felt guilty about it ever since.

Now there's a paper (found via GNXP.com) on a study of 1066 trainee truckers in the U.S.:
Cognitive Skills Explain Economic Preferences, Strategic Behavior, and Job Attachment, by Stephen V. Burks, Jeffrey P. Carpenter, Lorenz Götte, and Aldo Rustichini

In large firms of the type we study, the American Trucking Associations consistently report that annual turnover rates exceed 100% (21). Most driver trainees, including our subjects, borrow the cost of training from their new employer, a debt which is forgiven after twelve months of post‐training service, but which becomes payable in full upon earlier exit. Yet over half our subjects exit before twelve months, which makes predicting survival of considerable interest.

The social scientists gave the trainee truckers the Ravens non-verbal IQ test, an ETS test of numeracy, and had them play a quantitative game called Hit 15. They also had them engage in the kind of Vernon Smith behavioral economics experiments that help measure future orientation and the like.
Figure 4 displays the survival curves for distinct values of a typical socio‐economic variable (marital status), as well as for each quintile for the Hit 15 Index. The difference between married and un‐married is small, while the difference among the quintiles in any of the cognitive skills scores is large. Marital status is typical of other socio‐economic variables, such as credit score, number of dependents, prior job, and so on: these explain little of the variation in survival. The survival curves are similar for the IQ Index and the Numeracy. The difference between survival levels at different scores is particularly large for the Hit 15 Index: the survival for the top scorers is twice as large as for the bottom ones.

IQ, numeracy, and the Hit 15 game were all correlated with graduation rates from the one-year training program. The Hit 15 game was a particularly good predictor of who would graduate from the training program. Interestingly, the top quintile in numeracy had a worse graduation rate than the next highest quintile. Perhaps the most numerate tended to get alternative employment as bookkeepers, or whatever, jobs where you get to go home every evening.

Their abstract:
Economic analysis has said little about how an individual’s cognitive skills (CS's) are related to the individual’s preferences in different choice domains, such as risk-taking or saving, and how preferences in different domains are related to each other. Using a sample of 1,000 trainee truckers we report three findings. First, we show a strong and significant relationship between an individual’s cognitive skills and preferences, and between the preferences in different choice domains. The latter relationship may be counterintuitive: a patient individual, more inclined to save, is also more willing to take calculated risks. A second finding is that measures of cognitive skill predict social awareness and choices in a sequential Prisoner's Dilemma game. Subjects with higher CS's more accurately forecast others' behavior, and differentiate their behavior depending on the first mover’s choice, returning higher amount for a higher transfer, and lower for a lower one. After controlling for investment motives, subjects with higher CS’s also cooperate more as first movers. A third finding concerns on-the-job choices. Our subjects incur a significant financial debt for their training that is forgiven only after twelve months of service. Yet over half leave within the first year, and cognitive skills are also strong predictors of who exits too early, stronger than any other social, economic and personality measure in our data. These results suggest that cognitive skills affect the economic lives of individuals, by systematically changing preferences and choices in a way that favors the economic success of individuals with higher cognitive skills.

My published articles are archived at iSteve.com -- Steve Sailer

35 comments:

headache said...

In Africa trucking also seems to be reserved for the lesser skilled. But this attitude does not make economic sense. For instance in Europe it’s mostly a skilled profession with requisite training and qualifications. It makes sense too, since economical trucking is also about having knowledge about your equipment (truck), the goods you are delivering and the area in which you move. In addition traffic in Europe is heavy and roads tight. So numbskulls as drivers are likely to not only hike trucking costs but also cost the taxpayer cleaning up after accidents.

Lloyd G. said...

Reminds me of my time in basic training in the Army. The guys who had the hardest time with the rules and the routine were the college grads.
You want them smart enough to do the job, but not so smart that they're constantly questionning what they're doing.

sykes.1 said...

Reads like an abstract of the Bell Curve.

ironrailsironweights said...

It may well be that the smarter truckers are owner-operators rather than employees of trucking companies.

Peter

Anonymous said...

Based on this study, If I owned a trucking firm I would try to give my job applicants an IQ test and generally hire the ones with IQ from 100 to 105 and carefully avoid the ones with IQ above or below that range.

I know that some employers have been sued for using IQ tests in employment. Would this academic study give me enough ammunition to defend such a lawsuit?

Truth said...

"Interestingly, the top quintile in numeracy had a worse graduation rate than the next highest quintile. Perhaps the most numerate tended to get alternative employment as bookkeepers, or whatever, jobs where you get to go home every evening."

Again Steve, you can fit a square peg into a round hole provided it is made of soft enough material, and you use a large enough hammer.

The fact that these findings contradict the very findings of everything else you have professed should be cause for jubilation, not sophistry.

Have you ever heard the difference between a bad scientist and a good scientist?

The bad scientist creates a hypothesis and goes to the greatest possible length to prove it right...the good scientist creates a hypothesis and goes to the greatest possible length to prove it wrong.

robert61 said...

I drove trucks for a moving company when I was in college in Boston. The only parts that required intelligence were route-finding, which is no longer an issue thanks to GPS, packing the truck and dealing with the customers.

Some people are much better than others at using technological physical extensions of their body, such as surgeons, race car drivers, and guys who are great at first-person shooter games. Such spatial deftness is probably a specific inborn talent.

I am a major klutz when it comes to spatial relations. Maneuvering the streets demanded careful attention. I did well at the job, but I was like a powerful processor powering through a complex calculation despite a badly written algorithm.

I am sure that there are lots of guys with 90 IQs and a sweet touch who could have done the driving part of the job better than me with a lot less stress.

Anonymous said...

These results suggest that cognitive skills affect the economic lives of individuals, by systematically changing preferences and choices in a way that favors the economic success of individuals with higher cognitive skills.OMG! Who knew?!

--Senor Doug

Lucius Vorenus said...

Arthur Hu, in his Wonderlic-to-IQ conversion formula, calculates that the Wonderlic folks recommend an IQ of 100-108 in truck drivers.

PS: If the Pentagon is dumping two-digit soldiers in the truck-driving corps, then I'd hate to see their insurance stats.

Which begs the question: To what extent does the Pentagon even purchase private sector insurance? Are they suable, or do they have some sort of statutory indemnity?

Lucius Vorenus said...

Also, a little off-topic, but if it is correct [as the available evidence leads me to believe] that American Blacks & Aboriginal Hispanics now have an average IQ of about 80 [and falling, owing to dysgenic fertility], then an IQ of 108 is getting out about two standard deviations from their mean[s].

In other words, by American Black or Aboriginal Hispanic standards, you'd have to be something of a "genius" to pass the Wonderlic standards for a truck driver.

[Sorry to rain on everyone's Monday Morning Parade...]

Bill said...

A good trucker needs at least decent spatial skills. Ever seen guys back tractor-trailers up to loading docks? Not an easy job.

But truck driving in general is pretty mindless. Just stay awake and alert enough to keep the truck on the road and make the few requisite turns. Taxi driving probably requires more memory and spatial skills applied more frequently. One must remember thousands of streets, intersections and variables that affect traffic speed and ridership.

There's no doubt that smarter truckers and cabbies will be better than dumb ones, but smarter people can (usually) find something else to do that pays better. Trucking pays jack these days.

Anonymous said...

I drove an M1 Abrams in the Army, and I'm pretty sure driving a semi-trailer is tougher. The M1 has a motorcycle-style handlebar for steering and acceleration, one gigantic pedal for the brake, and an automatic transmission. Ignoring the pivot maneuver specific to tracked vehicles, it's less complex than driving a car with a manual transmission.

Reg Cæsar said...

a study of 1066 trainee truckers...1066 and all that?


...the lowest scorers allowed to enlist from 1992 thru 2004 were 92 IQs, who aren't stupid by any means.This reminds me of Arthur Jensen's remark in an interview with Jared Taylor, that there's probably an IQ floor of about 85 needed for professional basketball. Shrinks the window a bit.

I don't know how "mindless" truck driving is in practice. But that wouldn't stop the very smart from taking the job. I've met many intelligent and/or creative types on blue-collar jobs over the years, and know several blue-collar Mensans.

The great advantage of these jobs-- assuming they pay well-- is that one's mind is freed for one's own purposes. Eric Hoffer is the classic example.

Beats being a bookkeeper.

TomV said...

Truth:

The fact that these findings contradict the very findings of everything else you have professed

What findings contradict what findings? The study's conclusion is in line with everything else we know about cognitive skills:

These results suggest that cognitive skills affect the economic lives of individuals, by systematically changing preferences and choices in a way that favors the economic success of individuals with higher cognitive skills.

Now, this study is not about proving or disproving that high cognitive skill is best for everything, nor is Steve trying to do that here. If you run a truck company and want to recruit drivers in the fourth quintile in numeracy, that's certainly valid based on this study.

Steve was just speculating about why the top quintile doesn't come out on top. And his explanation is plausible. If you want to suggest, by contrast, that one can be too smart (read, nerdy) to drive a truck well, that's plausible, too. It would certainly fit the stereotype -- and we love stereotypes on this blog -- as in Ben Stiller's character in Flirting with Disaster. (Note, though, that although the top quintile loses to the fourth in graduation rate, it still beats the rest.)

Kenworth Keith said...

I am a former truck driver-former being a key word. Many very intelligent people were unable to physically drive the truck, in training-they never learned to back very well, and to be honest it never was my strong point. Some fairly low cognitives (by my estimate) in the classes I attended backed beautifully, though.

It's worth noting another breakdown by industry: LTL trucking companies have no serious driver retention or recruitment issues. They are union, they pay quite well, and drivers are home every other or,at worst, third day. Some every night.

Specialized carriers-guys who haul dangerous chemicals, weapons, outsize loads, etc, also have no serious retention problems. Those guys, like other truck load carriers, are out forever too, but those jobs pay very well.

IMO the "driver retention crisis" comes down to pay vs. lifestyle. A job that demands hard work, long hours, long absences from home, and living in a truck cab that doesn't pay munificently is not one many people will stay at if any alternatives exist.

beowulf said...

Hmmm, sort of proves your archnemesis Gladwell's point that work ethic is at least as important than IQ in determining professional success.

I'm wondering what the pay scale was. There's a reason that Costco's worker turnover is a fraction of Walmart's. Costco overpays its employees and Walmart underpays.

Steve Sailer said...

I used to drive to work through the wholesale food district just east of Chicago's loop, where 18 wheelers arrive early in the morning to drop off their loads for restaurants to turn into lunch. Truckdrivers have to be good at some complex backing up maneuvers. And they can't get flustered over the fact that they are blocking traffic when they back up into a loading dock. They have to feel they deserve to take their time to do it right and all the other motorists will just have wait for them.

Truth said...

"They have to feel they deserve to take their time...and all the other motorists will just have wait for them.

Hey, then black women would be the ultimate truck drivers!

David Davenport said...

For instance in Europe it’s mostly a skilled profession with requisite training and qualifications. It makes sense too, since economical trucking is also about having knowledge about your equipment (truck), the goods you are delivering and the area in which you move.In other words, truckers' unions in Euroland impose unnecessary requirements in order to restrict the quantity of truck drivers. :0~

Anonymous said...

A guy who I play cards with was a trucker. One of those who didnt make the one year cut off. He had 3 accidents while backing to the loading docks and was let go. Smart guy, heck of a cardplayer (poker is a mathy game to play it well you need to be fairly bright)
but apparently spatial skills not quite up to par.

josh said...

Interesting. I wonder if IQ has any predicitve value when it comes to the ability to be head of Homeland Security?

Anonymous said...

In other words, truckers' unions in Euroland impose unnecessary requirements in order to restrict the quantity of truck drivers. :0~ Just like every profession.

Does every doctor need a four year undergraduate degree and then the full four year medical school curriculum when, unless he is a GP, he will use only a fraction of what he has learned in any individual specialty?

Look at aviation. Colorblindness is a big disqualifier...but what is it intrinsically about aviation that male-pattern colorblindness causes an issue? Nothing. It's only that in the old days, red and green light signals were used and red and green markings are used in gauges. It would have been sensible at any time in the last 80 years to use a different marking on gauges, and if light signals are really needed (they're never used in paractice anymore) using dots and dashes-or even, any two different colrs besides red and green=would easily solve the issue.

All prosperity comes from restriction, whether by the nature of the job or arbitrary action.

DAJ said...

"...American Blacks & Aboriginal Hispanics now have an average IQ of about 80...."80? Where did you get that information? Murray? Rushton? Du Lion? Flynn?

Truth said...

"Does every doctor need a four year undergraduate degree and then the full four year medical school curriculum when, unless he is a GP, he will use only a fraction of what he has learned in any individual specialty?"

Good doctors see medicine with a holistic approach, thus making the total curriculum necessary. Additionally, I don't think most doctors know what their specialties will be until they have a well rounded education.

Each specialty requires a different amount of internship/residency, for instance I believe a psychiatrist needs 3 years total after medical school, whereas a brain surgeon needs 8.

Ronduck said...

Bill said...

But truck driving in general is pretty mindless. Just stay awake and alert enough to keep the truck on the road and make the few requisite turns.

A driver I know used to have to drive from west Phoenix to Las Vegas every night. He said that he would leave Phoenix, and suddenly arrive in Vegas without remembering the trip in between.

Anonymous said...

My late grandfather, the man who raised my mother, was a truck driver. He was not very smart and clearly had an I.Q. that put him at least in the low '90s. He was, however, a fantastic driver. He posed next to rig at 16 in a rare picture of him, went off to Korea as a Marine and killed many men, came back and worked as a roughneck for a little bit and then pursued his dream of driving trucks. He was very proud of his record and was recognized as a driver without incident for years.

My grandmother (IQ high 140s, long story) would ride with him in their old age and would deeply analyze all the different kinds of drivers. In other words, she would form stereotypes like crazy. The absolute worst drivers (on interstates) in her opinion of being all over America were young professional women around college towns.

Lucius Vorenus said...

DAJ: "...American Blacks & Aboriginal Hispanics now have an average IQ of about 80...." 80? Where did you get that information? Murray? Rushton? Du Lion? Flynn?

1) BLACKS:

In 2001, Roth et al estimated that American Blacks had an average IQ of 83.5.

But 58 percent to 60 percent of all black children are born to black women with IQs below the black mean.

And the women studied in 1979 by the National Longitudinal Study of Youth, who themselves had an average IQ of 83.7, had produced, by 1997, a successor generation of children with an average IQ of only 80.2.

2) ABORIGINAL HISPANICS:

Legal immigrants to the USA from Mexico have an average IQ of 82 - God only knows what the illegal immigrants have.

Guatemala has an average IQ of 79.

3) BOTTOM LINE:

I'd guess that American blacks of age 45+ might have an average IQ up around 83 or 84, but that in 2009, American black children in the age range of 0-15 probably have an average IQ in the high seventies.

And my guess would be pretty much the same for aboriginal Hispanics - if the legal immigrants have an average IQ of only 82, then I'd be shocked if the illegals didn't pull the entire average down into the seventies.

David said...

"The absolute worst drivers (on interstates) in her opinion of being all over America were young professional women around college towns."

Ha ha! I concur.

And that weird segment of the population seems to be increasing.

Anonymous said...

Truckdrivers have to be good at some complex backing up maneuvers.

Performing a backing maneuver isn't so much IQ as it is experience and understanding the pivot point of the truck.

And they can't get flustered over the fact that they are blocking traffic when they back up into a loading dock. They have to feel they deserve to take their time to do it right and all the other motorists will just have wait for them.


Damn straight. It's chutzpah. This ain't an interstate, pal, so deal with it. Same goes with blocking a lane on a crowded street where there's nowehere to park.

I paid my way through college as a (usually) part-time delivery driver for the express end of a parcel company. This is not long haul trucking, obviously, and there was a clear advantage to IQ in this case. A fill-in driver would be handed 80-100 stops in what may be an unfamiliar area and have to determine for himself how to run the route, making sure to make all his commitment times, etc. It's not an easy task, even with a map. GPS systems were not used.

BGC said...

It is probably relevant that the two major psychological predictors of job perfomance are (in order) IQ and the personality trait of Conscientiousness (C). But that IQ and C are not closely correlated.

This implies that at any given stratum of selection, although both higher IQ and C are predictive of better performance, there will tend to be a reciprocal relationship between IQ and Conscientiousness.

Major IQ researcher Adrian Furman of University College, London has shown this for undergraduate students: the higher IQ students tend to be less conscientious (clever but lazier) while the and the highly Conscientious students tend to be lower in IQ (harder working but dumber).

Probably this arises because UCL undergraduates are excellent but on average second tier, and the (rare) students who are very high in both IQ and C would tend to go to first tier colleges.

Among truck drivers, I would therefore expect the smartest (in IQ terms) to be less Conscientious on average (and more likely to drop-out) - because if a higher IQ person was also highly Conscientious they would probably take a better-paying job.

(In other words, the reason why the smartest truck driving recruits are doing the job of truck driving is on average likely to be that their personality is too low in Conscientiousness for them to stay in the educational system and get higher qualifications, or that they are too 'feckless' in their work habits to get a white collar job - or to keep such a job if they get it.)

Incidentally, this phenomenon of reciprocal IQ and C is seen even at the very highest levels of IQ. Terman's early 20th century follow up study of very high IQ Californians found that the lower-achieving group had higher levels of anti-social personality traits.

Those with very high IQ and sufficient C are often doing relatively high status, well paid jobs but those who have less conscientious or more abrasive/ difficult personalities may take less-skilled jobs - such as the ultra-high IQ author of this excellent essay on this phenomenon -

http://www.prometheussociety.org/articles/Outsiders.html

who worked as a security guard (and who was murdered in the course of his job).

SO, although IQ predicts perfomance across a wide range the correlation between IQ and perfomance is considerably less than 1, and the difference is usually attributable to personality.

Anonymous said...

"truck drivers who wouldn't get lost"

This is no longer a problem considering GPS units are now ubiquitous and cost less than $200-150 dollars nowadays.

Peter said...

Actually even with GPS people get lost all the time. Especially low IQ people who assume "GPS knows best". Google +GPS +railroad crossing or +GPS and +road under construction and you'll get plenty of stories of stupidity to entertain you.

Anonymous said...

Not to change the subject but the commenter on black IQ recently is right. Black IQ has become lower in the last 40 uears, I suspect mostly because of AFDC and other programs subsidizing welfare motherhood.

I run into old blacks who are fairly smart more often than young ones.

DAJ said...

Lucius V.,

Thanks for the citations. The data surely do not bode well. I did, however, notice this quote from Murray:

A total of 716 of them were tested with a highly g-loaded verbal test, the Peabody Picture Vocabulary Test (revised). The mean of the subset of mothers whose children were tested was 83.7. The mean of their children was 80.2. The mothers and children were tested with different instruments, so it should not be concluded that the black mean actually went down in the new generation. But these data certainly give no reason to think it went up.

ben tillman said...

I run into old blacks who are fairly smart more often than young ones.Do you really suppose the old blacks are a representative sample of their birth cohort?