[OPE-L] tendency for the general rate of intelligence to decline?

From: glevy@PRATT.EDU
Date: Thu Aug 31 2006 - 14:28:56 EDT

May 27, 2005
Falling rate of Intelligence?
by Edward
Conventional marxist theory used to argue that capitalism was doomed to
regular and deepening crisis due to the impact of a phenomen known as "the
falling rate of profit". Basically the idea runs as follows: since on the
marxist view labour is the only source of genuine wealth creation, and
capital accumulation means that the proportion of active labour to "dead
labour" (capital investment) tends to decline, then the "rate of profit"
will diminish accordingly. Now I certainly have no intention of going into
all this rigmorole, but I do remember some wit back in the seventies
suggesting that if this was the case, then, for example, we could argue
that intelligence must be falling, since the quantity of active human
brainpower as a proportion of accumulated knowledge (living to dead
"mental labour") was constantly diminishing.

Well, low and behold, a paper out this week at the NBER argues just this

The paper in question is: The Burden of Knowledge and the "Death of the
Renaissance Man": Is Innovation Getting Harder? Benjamin F Jones. Here's
the abstract.

This paper investigates, theoretically and empirically, a possibly
fundamental aspect of technological progress. If knowledge accumulates as
technology progresses, then successive generations of innovators may face
an increasing educational burden. Innovators can compensate in their
education by seeking narrower expertise, but narrowing expertise will
reduce their individual capacities, with implications for the organization
of innovative activity - a greater reliance on teamwork - and negative
implications for growth. I develop a formal model of this "knowledge
burden mechanism" and derive six testable predictions for innovators. Over
time, educational attainment will rise while increased specialization and
teamwork follow from a sufficiently rapid increase in the burden of
knowledge. In cross-section, the model predicts that specialization and
teamwork will be greater in deeper areas of knowledge while, surprisingly,
educational attainment will not vary across fields. I test these six
predictions using a micro-data set of individual inventors and find
evidence consistent with each prediction. The model thus provides a
parsimonious explanation for a range of empirical patterns of inventive
activity. Upward trends in academic collaboration and lengthening
doctorates, which have been noted in other research, can also be explained
by the model, as can much-debated trends relating productivity growth and
patent output to aggregate inventive effort. The knowledge burden
mechanism suggests that the nature of innovation is changing, with
negative implications for long-run economic growth.

The implications of this: well the most obvious is that more years of
study are required (the lengthening doctorates bit). This may not be as
detrimental from an economic point of view the author suggests, since
really it is possible to work and study at the same time, and what we may
be moving to is a society where the concept of lifelong education is the
important one.

An issue our author doesn't seem to consider: networking externalities.
The technology is changing. The arrival of the internet means that any
individual can process far more information far more rapidly today (oh
those lazy, sleepy afternoons in the library stacks, how I miss them,
yawn). So this is going to offset the accumulation of "dead" information

Also, of course, there are more people alive today, and a higher
proportion of them are engaged in some sort of research or other. The
first century Greek philosopher Plutarch famously speculated that there
might be more alive in his generation than the sum total of all those who
had lived in previous generations. This may well have been true of the
20th century also, and will possibly be true of the first half of this

One other paper the same author published this week seems to offer some
sort of hope for us "grey hairs":

Age and Great Invention
Benjamin F Jones.

Great achievements in knowledge are produced by older innovators today
than they were a century ago. Using data on Nobel Prize winners and great
inventors, I find that the age at which noted innovations are produced has
increased by approximately 6 years over the 20th Century. This trend is
consistent with a shift in the life-cycle productivity of great minds. It
is also consistent with an aging workforce. The paper employs a
semi-parametric maximum likelihood model to (1) test between these
competing explanations and (2) locate any specific shifts in life-cycle
productivity. The productivity explanation receives considerable support.
I find that innovators are much less productive at younger ages, beginning
to produce major ideas 8 years later at the end of the 20th Century than
they did at the beginning. Furthermore, the later start to the career is
not compensated for by increasing productivity beyond early middle age. I
show that these distinct shifts for knowledge-based careers are consistent
with a knowledge-based theory, where the accumulation of knowledge across
generations leads innovators to seek more education over time. More
generally, the results show that individual innovators are productive over
a narrowing span of their life cycle, a trend that reduces -- other things
equal -- the aggregate output of innovators. This drop in productivity is
particularly acute if innovators' raw ability is greatest when young.

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