I recently got a note from a fan of this blog who was
depressed because her IQ scores were not much above average. Her sadness
magnified when she read a research paper from a group of 16 researchers at
several prestigious universities who asserted that education after you are 20 years old doesn´t much improve your
intelligence. My reader said, “That is devastating for me, as it makes it clearer
that I´m pretty stuck in my "average" position. Do you think
that this analysis is clearly conclusive? Or is there still some way to
improve myself?”
She continued, “I
dream of finishing my degree in Electronical Engineering and then going for Physics,
but after seeing that analysis and lots of IQ charts for job positions and careers,
I’m pretty disappointed.”
Before addressing her
concerns, I need to summarize the paper that dismayed her. The report,
published in the prestigious Proceedings
of the National Academy of Sciences (PNSA) was based on what authors called
General Cognitive Ability (GCA), which they defined as any IQ-like
summary or principal component index of overall cognitive function. They admit
and referenced some studies that have found that additional education increases
intelligence, but their hypothesis was the opposite.
One thing the researchers did was conduct a basic meta-analysis
of seven studies (10 datasets) with pre- and post-comparisons. The basic
finding was that each additional year of education accounted for an average of
1.20 additional later-life IQ points.
My blog fan apparently missed the good news. That is easy to
do, because the paper was one of the most poorly written and confusing research
reports I have read over decades. This is what you might expect from anything
written by 16 academics. What I think the report said about the meta-analysis was
that each additional year of education accounted for an average of 1.20
additional later-life IQ points. You can see this as a glass half empty or half
full. The half full view is that four years of formal post-high school
education raises your IQ almost 5 points on average. Don’t bet the farm on this
conclusion. These studies had an excessive amount of uncontrolled variables.
The PNAS paper did cite a study reporting that completing a
university education led to a midlife gain of gains of 6–22.4 IQ points over
adolescent cognitive ability compared with individuals who did not attend
university. The students in that study were tested for IQ at age 15. That means
that the average IQ of 100 could have jumped to 122, which is definitely
adequate for most intellectually challenging careers. And this assumes just
four years of ordinary college, without regard to major or rigor of
intellectual challenge. Trust me, all college education is not equal.
These authors also conducted their own study and found
little effect of education on IQ in an all-male, predominantly white,
non-Hispanic sample at age 56-66. For example, averaging data across a large
pool of subjects, they report that GCA accounted for 40% of GCA variance in
late midlife and approximately 10% of variance in each of seven other cognitive
domains. Averaging obscures the detection of individuals who could have had
large GCA gains from education and life experience. Moreover, the kind of
education and life experience must surely have varied widely and was not
accounted for in the study. Even so, 60% of the variance in CGA did NOT depend
on the test scores the men had taken when they were 20 years old. Don’t forget
that 90% of late-life GCA variance was influenced by something other than
formal education.
The IQ-like test they used was a military qualification test
(AFQT), known to correlate well with established IQ tests. All their subjects,
military veterans, took the test around age 20 and again about three decades
later. Their data were interpreted to indicate that education does not make one
much smarter. One result seemed especially clear: individuals with higher
intellectual capacity tend to attain more education, achieve higher
occupational status, and engage more in cognitive-intellectual activities.
There was an association of education, occupational
complexity, and cognitive-intellectual activities with better later-life
cognitive functioning, but these associations are not the cause of late-life
ability. In other words, smart people are smarter when they are older because they
were smarter to begin with. They became educated because they were already
smart enough to seek it, not that education made them smart. The authors did
concede that they were unable to definitively confirm their hypotheses
regarding possible sensitive periods for brain development and the age of
baseline testing. Such confirmation would require testing at multiple time
points before the completion of education all within the same study.
One clear take-home message is that most intellectual gains
occur before the age of 20. This is why elementary and secondary school
education are crucial for creating optimal intelligence. As a professor for
over 50 years, I am convinced that public schools today are not doing as much
to make youngsters smarter as was the case in previous decades. That does not
mean that further gains cannot be obtained after age 20. Education and intellectually
challenging life experience do produce intelligence gains, just not as much as
they do in youngsters.
The preference of researchers for averaging data obscures
finding out what happens for a particular person. Is a person age 20 with low
IQ more or less able to benefit from education than a person with a higher
initial IQ? Or is it the other way around? Would the effect of education be
different for women or minorities?
The kind of education and intellectual life challenge surely
matter. For example, do we really expect the same mental benefit from four
years of being a college physics major as an education major? Think also about
still more benefit from a rigorous, emphasize rigorous, PhD program. Do we
expect the same results from someone with little post-college training compared
to a life-long learner?
IQ scores are affected by many things besides education that
can affect how we interpret any effects of education. What about the age at
which IQ is first tested? Brain development occurs throughout youth and extends
past age 20. Obviously, IQ tests in elementary school are less valid than test
results obtained after puberty.
Other variables affect IQ scores as well, particularly the
mental state of the individual when the test was taken. Factors that will
surely decrease scores, independently of actual cognitive ability, include
sleep deficiency, emotional stress, and persistent mental distraction.
Consider especially stress. The persistent release of
cortisol in chronic stress shrinks neuronal synapses and surely diminishes
cognitive ability. The pool of veterans in this study must surely have varied
widely in the amount of stress the men experienced during their military years.
Some surely had combat-related PTSD, while others had non-stressful jobs.
One other thing: IQ tests not only measure how well you can
figure things out, but only certain kinds of things, especially analogies. They
also measure how fast you can solve a problem. Sometimes it doesn’t matter how
long it takes to solve a problem. Einstein worked on special relativity for at
least 10 years, despite claims of some others that it was a lightning-flash eureka
moment.
What is my advice to my blog follower, and all those others,
including me, with unimpressive IQs? First, do what you love that is helpful to
you and others. But do not allow your reach to exceed your grasp. As the Army
says, “Be all you can be.” The turtle
sometimes beats the hare. But accept that the hare usually wins. Do not obsess or
become stressed over your limitations, for that is counterproductive.
You should be happy and bring happiness to others. That
should suffice. You don’t need the ability to invent relativity to be happy or
make a meaningful contribution to others.
Source:
Kremen, William S. et al. (2019). Influence of young adult
cognitive ability and additional education on later-life cognition. PNAS. 116(6),
2021-2026.
