The Genius in All of Us: New Insights Into Genetics, Talent, and IQ (27 page)

Amazingly, there is no architect. Like ant colonies, galaxies, and other complex emergent systems, the human body is a dynamic assembly abiding by certain strict laws of science but not following any master set of instructions. The outcome is a function of the ingredients and the process.

The University of Virginia’s Eric Turkheimer explains it this way: “Individual genes and their environments interact to initiate a complex developmental
process that determines adult personality. Most characteristic of this process is its interactivity. Subsequent environments to which the organism is exposed depend on earlier states, and each new environment changes the developmental trajectory, which affects future expression of genes, and so forth. Everything is interactive, in the sense that no arrows proceed uninterrupted from cause to effect; any individual gene or environmental event produces an effect only by interacting with other genes and environments.”

The point here is not to suggest that every person has exactly the same biological advantages or limits, or exactly the same potential. We clearly do not. But understanding each person’s true potential is not something we’ll ever be able to do from a genetic snapshot. Too many developmental factors matter too much. When it comes to complex traits like intelligence and talent, we need to drop casual use of the word “innate” and instead strive to understand as much as we can about the gene-influenced, environment-mediated process called human development.

While the scientific use of the word “innate” is still under intense discussion among biologists, it’s clear enough that its popular use to refer to fixed, built-in, predetermined causes of complex traits is simply no longer supportable. It has become obsolete.

Like the popular use of the word “genes,” it is a mere stand-in for things we don’t understand about how we become who we are, a shorthand for the rich and enigmatic incubator of temperament, inclinations, and abilities. (Turkheimer, “Three laws of behavior genetics and what they mean,” p. 161. Bateson and Mameli, “The innate and the acquired.”)

    
Dynamic development was one of the big ideas of the twentieth century, and remains so
.

   Without an infectious symbol like E = mc
²
or a phrase like “nature versus nurture,” this idea has been difficult to introduce to the public; few even bothered to try. Several decades passed while this transformative idea languished in obscurity and was eclipsed by other, more enthralling genetic headlines about Dolly the sheep, the Human Genome Project, “criminal genes,” and so on.

It languishes still. Meanwhile, in classrooms and baby nurseries everywhere, the oppressive reign of the gene-gift paradigm continues.

CHAPTER 2:
INTELLIGENCE IS A PROCESS, NOT A THING

PRIMARY SOURCES

American Psychological Association. “Intelligence: Knowns and Unknowns. Report of a Task Force Established by the Board of Scientific Affairs of the American Psychological Association.” Released August 7, 1995.

Ceci, S. J.
On Intelligence: A Bio-ecological Treatise on Intellectual Development
. Harvard University Press, 1996.

Cravens, H. “A scientific project locked in time: the Terman Genetic Studies of Genius.”
American Psychologist
47, no. 2 (February 1992): 183– 89.

Dickens, William T., and James R. Flynn. “Heritability estimates versus large environmental effects: the IQ paradox resolved.”
Psychological Review
108, no. 2 (2001): 346–69.

Dodge, Kenneth A. “The nature-nurture debate and public policy.”
Merrill-Palmer Quarterly
50, no. 4 (2004): 418–27.

Flynn, J. R. “Beyond the Flynn Effect: Solution to All Outstanding Problems Except Enhancing Wisdom.” Lecture at the Psychometrics Centre, Cambridge Assessment Group, University of Cambridge, December 16, 2006.

Locurto, Charles.
Sense and Nonsense about IQ
. Praeger, 1991.

Risley, Todd R., and Betty Hart.
Meaningful Differences in the Everyday Experience of Young American Children
. Paul H. Brookes Publishing, 1995.

Schönemann, Peter H. “On models and muddles of heritability.”
Genetica
99, no. 2/3 (March 1997): 97–108.

Sternberg, Robert J. “Intelligence, Competence, and Expertise.” In
Handbook of Competence and Motivation
, edited by A. J. Elliot and C. S. Dweck. Guilford Publications, 2005.

Sternberg, Robert J., and Janet E. Davidson.
Conceptions of Giftedness
. 1st ed. Cambridge University Press, 1986.

Sternberg, Robert J., and Elena Grigorenko. “The predictive value of IQ.”
Merrill-Palmer Quarterly
47, no. 1 (2001): 1–41.

CHAPTER NOTES

    
[Some] assert that an individual’s intelligence is a fixed quantity
.

Longer version: “[Some] assert that an individual’s intelligence is a fixed quantity which cannot be increased. We must protest and react against this brutal pessimism … With practice, training, and above all method, we manage to increase our attention, our memory, our judgment, and literally to become more
intelligent than we were before.” (Binet,
Les idées modernes sur les enfants
; this work has been reprinted in Elliot and Dweck, eds.,
Handbook of Competence and Motivation;
see p. 124.)

    
The good news is that, once learned, The Knowledge becomes literally embedded in the taxi driver’s brain
.

Eleanor Maguire writes:

Our finding that the posterior hippocampus increases in volume when there is occupational dependence on spatial navigation is evidence for functional differentiation within the hippocampus. In humans, as in other animals, the posterior hippocampus seems to be preferentially involved when previously learned spatial information is used, whereas the anterior hippocampal region may be more involved (in combination with the posterior hippocampus) during the encoding of new environmental layouts.

A basic spatial representation of London is established in the taxi drivers by the time The Knowledge is complete. This representation of the city is much more extensive in taxi drivers than in the control subjects. Among the taxi drivers, there is, over time and with experience, a further fine-tuning of the spatial representation of London, permitting increasing understanding of how routes and places relate to each other. Our results suggest that the “mental map” of the city is stored in the posterior hippocampus and is accommodated by an increase in tissue volume. (Maguire et al., “Navigation-related structural change in the hippocampi of taxi drivers,” pp. 4398–403.)

    
Further, her conclusion was perfectly consistent with what others have discovered in recent studies of violinists, Braille readers, meditation practitioners, and recovering stroke victims
:
that specific parts of the brain adapt and organize themselves in response to specific experience.

Leon Eisenberg surveys the evidence:

Colleagues … compared magnetoencephalographic recordings from experienced violinists with those from nonmusicians and found a substantially larger cortical representation of the fingers of the left hand (the one used to play the strings) than of the fingers of the right (or bowing) arm and more brain area dedicated to representation of fingers in the musicians than in the corresponding recordings from the nonmusicians.

A second example … is that the planum temporale is larger on the left
than on the right in the musicians; the asymmetry is most marked in those with perfect pitch.

[Another study] found a substantial enlargement of hand representation in the three-finger Braille readers.

The cortex has a remarkable capacity for remodeling after environmental change
. (Italics mine.) (Eisenberg, “Nature, niche, and nurture,” 213–22.)

Eisenberg’s citations:

Schlaug G., L. Jancke, Y. Huang, et al. “Asymmetry in musicians.”
Science
267 (1995): 699–701.

Elbert, Thomas, Christo Pantev, Christian Wienbruch, Brigitte Rockstroh, and Edward Taub. “Increased cortical representation of the fingers of the left hand in string players.”
Science
270 (1995): 305–7.

Sterr, A., M. M. Muller, T. Elbert, et al. “Changed perceptions in Braille readers.”
Nature
391 (1998): 134–35.

Yang, T. T., C. C. Gallen, and B. Schwartz. “Sensory maps in the human brain.”
Nature
368 (1994): 592–93.

Yang T. T., C. C. Gallen, V. S. Ramachandran, et al. “Noninvasive detection of cerebral plasticity in adult human somatosensory cortex.”
Neuroreport
5 (1994): 701–4.

Ramachandran, V. S., D. Rogers-Ramachandran, and M. Stewart. “Perceptual correlates of massive cortical reorganization.”
Science
258 (1992): 1159–60.

Ramachandran, V. S. “Behavioral and magnetoencephalographic correlates of plasticity in the adult human brain.”
Proceedings of the National Academy of Sciences
90 (1993): 10413–20.

Mogilner A., J. A. I. Grossman, and V. Ribary. “Somatosensory cortical plasticity in adult humans revealed by magnetoencephalography.”
Proceedings of the National Academy of Sciences
90 (1993): 3593–97.

    
This is our famous “plasticity
”:
every human brain’s built-in capacity to become, over time, what we demand of it.

   There are, of course, strict limits to plasticity. Every functioning human brain has an intricate and unchanging design, billions of years in the making. Various lobes and neural pathways are dedicated to specific functions: language, sensory input, consciousness, logical thought, abstract thought, spatial representation, and so on. The mind is not a blank slate. But this evolved design also includes an enormous capacity to learn and adapt, to hold specialized knowledge and wield specialized skills.

    
Psychological methods of measuring intelligence
:
Terman,
Genetic Studies of Genius
, vol. 1, p. v.

    
Terman was part of a well-established movement convinced that intelligence was an inborn asset, inherited through genes, fixed at birth, and stable throughout life
.

   Terman’s direct mentor was the prominent psychologist (and first president of the American Psychological Association) G. Stanley Hall. H. Cravens writes:

From his mentor, [G. Stanley] Hall, Terman learned that biological inheritance was all-powerful in determining the psyches and actions of animals and men … Hall’s genetic psychology was a grand vision; simply put, Hall taught that minds have evolved through definite stages or types, from those of the lowliest cockroach to those of comparatively intellectual mammals and, finally, to those of the lower races, of children, of women, and then of rational White men. Hallian genetic psychology offered an overall hypothesis for Terman during his scientific career. (Cravens, “A Scientific Project Locked in Time.”)