Five Recommended Articles Regarding the Neurological Basis of Intelligence

 

  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 have higher IQs by 11 years old was tested in 1,795 children on whom behavioral measures of stimulation seeking were taken at 3 years, together with cognitive ability at 11 years. High 3-year-old stimulation seekers scored 12 points higher on total IQ at age 11 compared with low stimulation seekers and also had superior scholastic and reading ability. Results replicated across independent samples and were found for all gender and ethnic groups. Effect sizes for the relationship between age 3 stimulation seeking and age 11 IQ ranged from 0.52 to 0.87. Findings appear to be the first to show a prospective link between stimulation seeking and intelligence. It is hypothesized that young stimulation seekers create for themselves an enriched environment that stimulates cognitive development.

 

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 Topic List for further reading.