more re Jensen

From: Mike Cole (mcole@weber.ucsd.edu)
Date: Sat Dec 18 1999 - 13:54:59 PST


The commentaries on this issue strike me as more than usually informative
of a range of current thinking on heritability and IQ so I am passing
this along. Delete if you are not interested.
mike
>From: PSYCOLOQUY <journal@princeton.edu>
Subject: psyc.99.10.067.intelligence-g-factor.13.kush (207 lines)

PSYCOLOQUY is sponsored by the American Psychological Association (APA)
                Copyright 1999 Joseph C. Kush

        THE G FACTOR: IMPLICATIONS FOR SCHOOL PSYCHOLOGISTS
        Book Review of Jensen on Intelligence-g-factor

        Joseph C. Kush
        Department of Counselling, Psychology and Special Education
        412B Canevin Hall
        Duquesne University
        Pittsburgh, PA 15282-5585
        kush@duq.edu

    ABSTRACT: Arthur Jensen's (1998, 1999) new book, "The G-Factor: The
    Science of Mental Ability," examines the historical evolution of
    the g factor as well as many of the modern-day implications of this
    development for psychologists. The implications of his findings for
    school psychologists are discussed, as are suggestions for future
    research.

1. Nondiscriminatory assessment is a source of considerable legal and
ethical consequence to school psychologists, particularly for those who
work with ethnically diverse populations, when the selection of test
instruments which are free of test bias is of paramount importance.
Jensen's previous (1980) work, "Bias in Mental Testing," presented a
comprehensive review and evaluation of cultural bias (or lack of it) in
psychological tests and reflects the "gold standard" text in a school
psychologist's library. While his newest work, "The G-Factor: The
Science of Mental Ability, focuses less on commercially available tests
of intelligence," (1998, 1999) it remains an important contribution to
the scientific study of test bias.

2. Jensen's first several chapters review the history of intelligence
testing, beginning with the philosophical contribution of Plato and
Aristotle, and continuing with a review of the work of Galton and the
subsequent development of the first modern-day (Binet's) test of
intelligence in 1905. Jensen proceeds by reviewing alternative
conceptualisations of g and corresponding historical and modern-day
theories of intelligence. Many currently available commercial tests of
intelligence have been increasingly criticised for their lack of a
strong theoretical foundation. Perhaps due to the recent popularity of
theories of multiple intelligences, successive revisions of many IQ
tests have evolved to measure increasing numbers of "intelligences".
For example, the newest editions of both the Stanford Binet (Stanford
Binet IV) and the Wechsler Intelligence Scale for Children-Third
Edition (WISC-III) now claim to measure four intelligence "factors"
without any corresponding change in the theories underlying the tests.
Because it remains unclear how many "types" of intelligence are being
measured by these scales, there currently exists marked disagreement
among school psychologists regarding their level of diagnostic
interpretability (Kush, 1996). Jensen's early chapters clearly point
out the critical importance of the need for a greater alliance between
theories of intelligence and tests of intelligence.

3. There is also considerable attention in the book to the distinction
between measures of learning and measures of intelligence. This
distinction is critical for school psychologists who assess children
and make recommendations for remediation and interventions. Certainly,
all children are capable of learning; however, their rates of and
capacities for learning are not uniform and Jensen carefully and
thoughtfully reviews the professional and public implications of this
distinction. As Jensen correctly points out, no educator enjoys telling
a parent that their child has a low IQ or is doing poorly in school; as
a result, theories of multiple intelligence have become a popular
alternative -- parents can now be told that while their child may be
lacking in one type of intelligence, there remain many other types in
which they can still excel. This egalitarian fallacy -- that all human
subgroups are equal in traits measured by IQ tests -- is directly
challenged by Jensen, and the limitations of theories of multiple
intelligences are carefully reviewed. Success in school develops from
the interaction between intelligence and learning and an appreciation
of the distinction between what is genetic and what is learned from the
environment is perhaps the greatest contribution of The G Factor.

4. For school psychologists, perhaps the most fundamental utility of an
IQ test is the prediction of school success/failure or academic
achievement. Commercial IQ tests, like the WISC-III, are often the best
predictors of school success available to school psychologists, and
many school psychologists have suggested that the term IQ-test be
replaced with terminology with less "emotional baggage" such as School
Success Indicator, or School Achievement Forecast. Most commercially
available tests of intelligence are highly correlated (typically .55 to
.65) with tests of achievement because their item content includes
g-related tasks as well as tasks that are clearly reflective of
environmentally learned material (e.g., How far is it from San
Francisco to Paris?; What are the four seasons of the year?). While
this combination of tasks-of-intelligence with tasks-of-learning
improves the predictive power of commercial IQ tests, it also creates
situations where school psychologists are often forced to defend IQ
test questions that appear culturally loaded. Jensen's research
suggests that reaction time and inspection time tasks are much purer
measures of "true" intelligence and will offer school psychologists a
more face-valid alternative to traditional commercial IQ tests.
However, the result may come with a loss in predictive power and school
psychologists may face the dilemma of choosing between more
experimental measures of pure intelligence with weaker forecasting
ability and traditional tests of intelligence which are contaminated
with non g-related subtests but yield stronger correlations with
academic achievement.

5. Attempts to improve the predictive power of commercial IQ tests
(beyond g) have, for the most part, proven unsuccessful. For example,
one attempt in school psychology that has gained recent popularity is
the cross battery approach related to Cattell and Horn's notion of
fluid (Gf) and crystallised (Gc) intelligence. Jensen correctly points
out that it is not yet clear how the Gf factor is substantially
distinct from the higher-order g factor; however, greater attention
could have been given to the additional criticism that Gc may actually
be a measure of achievement rather than intelligence. Psychologists
continue to debate whether questions such as "If Katharine has 4 apples
and eats one of them, how many will she have left?" are measures of
intelligence (numerical reasoning) or measures of achievement
(mathematics calculation). It should come as no surprise that an
increased predictive validity coefficient is produced when this type of
question occurs on both the predictor (IQ) as well as the criterion
(achievement) measure. Greater attention to problems such as this would
have strengthened the practical utility of the book.

6. Empirical evidence for comparable predictive validities of measures
of g across ethnic groups is also carefully reviewed by Jensen, and
continues to show that these measures are free of psychometric bias.
The literature reviewed by Jensen describing subgroup similarities and
differences in tasks of reaction time and inspection time will be
particularly interesting for school psychologists. Additional research
examining possible differential predictions of academic achievement
from these reaction time and inspection time tasks, across
developmental stages and across ethnic groups, also remain to be
completed.

7. Despite the carefully outlined presentation supporting Jensen's
claims for the importance of g, critics will undoubtedly continue to
challenge his findings. Most proponents of the cultural test bias
hypothesis, with the notable exception of Flynn (1987), tend to make
these arguments from theoretical rather than data-driven positions.
Although Jensen provides much evidence to refute many of these claims,
several criticisms receive only minimal attention. Helms (1992), for
example, argues that most g-related tasks are European centred,
emphasising (among other things) "action orientation" and
"competition". "African-centered" values, in contrast, emphasise
"spirituality", "harmony" and "social time". Similarly, Ogbu (1994) has
argued that research examining ethnic differences in IQ tests must
recognise a distinction between voluntary or immigrant minorities and
involuntary or nonimmigrant minorities. Ogbu suggests that voluntary
and involuntary minorities develop different cognitive frames of
reference toward many things, including IQ test performance, depending
on whether they or their ancestors freely chose to come to their new
country or were forced to emigrate.

8. These criticisms have important implications, and while Jensen does
provide some rebuttals to these arguments (e.g., comparable factorial
and predictive validities; p. 512), a more detailed response would
certainly have proven beneficial to school psychologists, who are
currently wrestling with this issue. Jensen would probably agree with
Hull's (1988) belief that science (including psychology) works much
like evolution, so that over time only the better data and better
theories will survive. Despite our frequent frustration at the pace at
which the test fairness debate is evolving (and often de-evolving),
Jensen's book reminds us that ultimately psychology as a science must
be supported by rigorous and empirically replicated research rather
than politically correct propaganda.

9. Overall, Jensen's book has much to offer both practising and
research oriented school psychologists. It represents a welcome and
much needed contribution to the field and should become required
reading for all advanced level, graduate students in school
psychology.

REFERENCES

Flynn, J. R. (1987). Race and IQ: Jensen's case refuted. In S. Modgil
& C. Modgil (Eds.), Arthur Jensen: Consensus and controversy (pp.
221-232). New York: Falmer.

Helms, J. E. (1992). Why is there no study of cultural equivalence in
standardised cognitive ability testing? American Psychologist, 47,
1083-1101.

Hull, D. L. (1988). Science as a process. Chicago: University of
Chicago Press.

Jensen, A. R. (1980). Bias in mental testing. New York: Free Press.

Jensen, A. (1998). The g Factor: The Science of Mental Ability. Praeger

Jensen, A. (1999). Precis of: "The g Factor: The Science of Mental
Ability" PSYCOLOQUY 10 (023).
ftp://ftp.princeton.edu/pub/harnad/Psycoloquy/1999.volume.10/
psyc.99.10.023.intelligence-g-factor.1.jensen
http://www.cogsci.soton.ac.uk/cgi/psyc/newpsy?10.023

Kush, J. C. (1996). Factor structure of the WISC-III for students with
learning disabilities. Journal of Psychoeducational Assessment, 14,
32-40.

Ogbu, J. U. (1994). Culture and intelligence. In R. J. Sternberg (Ed.),
Encyclopedia of human intelligence, Vol. 2 (pp. 328-338). New York:
Macmillan.



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