A reader has graciously
forwarded these five intriguing articles advancing their authors'
ideas concerning the neurological, behavioral, and/or evolutionary
underpinnings of intelligence.
o UNDERSTANDING
THE NATURE OF THE GENERAL FACTOR OF INTELLIGENCE:
THE ROLE OF INDIVIDUAL DIFFERENCES IN NEURAL PLASTICITY AS AN
EXPLANATORY MECHANISM
Dennis Garlick
University of Sydney
The nature of the general factor
of intelligence, or g, is examined. This article begins by observing
that the finding of a general factor of intelligence appears to
be inconsistent with current findings in neuroscience and cognitive
science, where specific connections are argued to be critical
for different intellectual abilities and the brain is argued to
develop these connections in response to environmental stimuli.
However, it is then observed that if people differed in neural
plasticity, or the ability to adapt their connections to the environment,
then those highly developed in one intellectual ability would
be highly developed in other intellectual abilities as well. Simulations
are then used to confirm that such a pattern would be obtained.
Such a model is also shown to account for many other findings
in the field of intelligence that are currently unexplained. A
critical period for intellectual development is then emphasized.
o STIMULATION
SEEKING AND INTELLIGENCE: A PROSPECTIVE lONGITUDINAL STUDY
Adrian Raine
University of Southern California
Chandra Reynolds
University of California, Riverside
Peter H. Venables
University of Southern California and University of York
Sarnoff A. Mednick
University of Southern California
The prediction that high stimulation
seeking 3-year-olds would
o HUMAN
EVOLUTION EXPANDED BRAINS TO INCREASE EXPERTISE CAPACITY, NOT
IQ,
Target Article on Brain-Expertise
Dr. John R. Skoyles
6 Denning Road,
Hampstead,
London, NW3 1SU
United Kingdom
http://www.users.globalnet.co.uk/~skoyles/index.htm
skoyles@globalnet.co.uk
Abstract: Why do modern humans
have larger brains than earlier people such as Homo erectus? As
large brains cause problems in childbirth, infancy and locomotion,
the advantage they offer must be substantial. This advantage might
be associated with increased IQ, but there is a problem: evidence
from MRI volumetric surveys, microcephaly and hemispherectomy
shows that there exist individuals with psychometrically normal
IQ but Homo-erectus-sized brains. Why did evolution increase brain
size (with its associated costs) when humans (as these individuals
demonstrate) can have normal IQ without bigger brains? I propose
that the advantage may be related to increased capacity for an
aspect of intelligent behaviour not measured by IQ tests but critical
to the survival of our simple hunter-gatherers ancestors: the
capacity to develop expertise.
o MYOPIA,
INTELLIGENCE, AND THE EXPANDING HUMAN NEOCORTEX
[International Journal of Neuroscience
(1999), 98(3-4):
153-276]
Precis of Storfer on Brain-Intelligence
Miles David Storfer
The Foundation for Brain Research
46 Brittany A Drive
Delray Beach FL 33446
USA
brainfoundation@aol.com
Abstract: During the past century,
a substantial increase has occurred in the size of the human brain,
especially in 'association' areas of the neocortex heavily used
to cope with a complex language-driven society. It is proposed
that this neocortical expansion has made possible the large, gradual
increase in IQ that has occurred across the developed world, and
been responsible for the dramatic upsurge in the prevalence and
severity of near-sightedness (myopia) usually found after societies
urbanize. The impetus for these changes begins during prenatal
development. Findings from studies of mammals reared in captivity
suggest that there is a mechanism for adaptive epigenetic inheritance,
one capable of modifying the timing and/or extent of gene expression
prenatally, without altering the DNA sequences that comprise protein-coding
and other structural genes. Mechanisms that appear capable of
transporting such adaptive changes across the so-called 'germ-line
barrier' -- without violating the basic precepts of Darwin's theory
-- are proposed. The social and evolutionary ramifications of
our apparent proclivity for rapid, progressive, adaptive neocortical
change are discussed, as well as some ways of testing aspects
of this theory are proposed.
The full text can be viewed and downloaded at no cost through
the publisher's (Gordon and Breach) website: In the US: http://www.gbhap.com/IJN
{note: the letters IJN must be capitalized}. Outside the US: http://www.gbhap-us.com/IJN
may be required.
o THE EVOLUTIONARY PSYCHOLOGY OF PERFECTIONISM
Reply to Prudkov on Brain-Expertise
Dr. John R. Skoyles
6 Denning Road,
Hampstead,
London, NW3 1SU
United Kingdom
http://www.users.globalnet.co.uk/~skoyles/index.htm
skoyles@globalnet.co.uk
Abstract: Prudkov (1999) suggests
an alternative to my proposal (Skoyles, 1999a) that the near doubling
of human brain size since Homo erectus arose to increase our capacity
for expertise. His criticism is that long term motivations are
needed for the acquisition of expertise. Prudkov has identified
a weakness in the present literature in the subfield that studies
expertise: what is the nature and origin of the motivation --
perfectionism -- that leads people to engage in the prolonged
practice needed to become experts? I show that this motivation
is peculiar, species- specific and appears to be central to human
evolution. However, it complements rather than replaces (as suggested
by Prudkov) the role of expertise in the evolutionary near doubling
of human brain size.
The reader has also referenced the Psycoloquy
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