Monday, October 29, 2007

Random tidbits from the mind blogosphere 10-29-07



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What is intelligence: Beyond the Flynn Effect


It looks like James Flynn (of the infamous "Flynn Effect" fame) has just published a new book on intelligence. I've not read it nor do I have a copy. This is an fyi post.

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Friday, October 19, 2007

Cognitive efficiency (working memory+Gs) = necessary but not sufficient constructs for learning?

As promised, here are a few thoughts from my Friday afternoon synaptic symphony of musings related to Geary's article on math learning.

On page 482 Geary talks about the core cognitive mechanisms (of working memory and Gf) being mental speed of information processing and attentional control (which I interpret as Engle, Conway et al.'s executive controlled attention). The overlap of these constructs with working memory and Gs (what we, in the land of the WJ III, call cognitive efficiency) is very interesting. In recent presentations I've referred to these core abilities as domain-general constructs...as recent CHC research suggests they are important for learning across almost all domains of human learning, esp. during initial stages of learning. These contrast with domain-specific abilities that appear more specific to learning in specific achievement domains (e.g., Ga and reading; Gf and mathematics).

I like his statement that these mechanisms are "necessary but not sufficient" for the development of secondary abilities (e.g., mathematics; reading). This makes sense. Domain general cognitive efficiency may be a set of necessary, but not sufficient, abilities for learning. They are necessary to learn, but the development of secondary abilities (such as reading and math) may require the addition of other abilities (Glr, Gf, Ga, Gv, etc.)) above and beyond cognitive efficiency.

This also connects with some causal models I've run where working memory, memory span, and Gs are specified as causal mechanism behind other cognitive abilities and achievement.

Just some Friday afternoon musings and thoughts as I "connect some dots" in my quirky store of acquired knowledge.

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Math learning and LD: Synthesis article by Geary

Every so often I run across a book or journal article that, in my opinion, resonates with considerable clarity re: something important regarding human intelligence and or understanding learning and or learning disabilities. I'm not sure if these readings, as viewed by others, would be accorded similar value, or if the readings just hit me at a time when I'm trying to "connect the dots" across the diverse literature that I skim on a routine basis.

I just finished skimming one such article. The article is by David Geary in Developmental Neuropsychology (2007, vol 32[1], p. 471-519; click here to view). The title of the article is "An evolutionary perspective on learning disabilities in mathematics." I try to read anything that David Geary writes as, IMHO, he is one of the top notch intelligence/cognitive scholars of our times, particularly as his research relates to helping us understand an important aspect of school learning--mathematics.

I plan (hope) to make a number of posts as I distill the essence of what he has written. The real beauty of this article is that it is a grand synthesis article that puts, in one place, his current synthesis of contemporary research on the development of mathematics and possible causes of math learning disabilities.

At this time I'm just alerting my readers to the article and making it available for viewing. Although some of the evolutionary material may be a bit difficult to digest, and does not have direct application to applied intelligence testing and interventions, the remainder of the article is packed with useful summary statements regarding the potential cognitive mechanisms, underlying neuroanatomy, etc. of mathematical learning.

More to come. But in the meantime, please read and digest on your own pace. I urge readers to take the time to become familiar with this article, as well as other research published by David Geary (a select list is below).

  • Fink, B., Brookes, H., Neave, N., Manning, J. T., & Geary, D. C. (2006). Second to fourth digit ratio and numerical competence in children. Brain and Cognition, 61(2), 211-218.
  • Geary, D. C. (2001). The development of intelligence, by M. Anderson. Contemporary Psychology APA Review of Books, 46(1), 23-25.
  • Geary, D. C. (1999). Evolution and developmental sex differences. Current Directions in Psychological Science, 8(4), 115-120.
  • Geary, D. C. (2007). An evolutionary perspective on learning disability in mathematics. Developmental Neuropsychology, 32(1), 471-519.
  • Geary, D. C. (2006). Gender differences in mathematics: An integrative psychological approach, by A.M. Gallagher, J.C. Kaufman. British Journal of Educational Studies, 54(2), 245-246.
  • Geary, D. C. (1993). Mathematical disabilities: Cognitive, neuropsychological, and genetic components. Psychological Bulletin, 114(2), 345-362.
  • Geary, D. C. (2004). Mathematics and learning disabilities. Journal of Learning Disabilities, 37(1), 4-15.
  • Geary, D. C. (2005). Role of cognitive theory in the study of learning disability in mathematics. Journal of Learning Disabilities, 38(4), 305-307.
  • Geary, D. C., Hamson, C. O., & Hoard, M. K. (2000). Numerical and arithmetical cognition: A longitudinal study of process and concept deficits in children with learning disability. Journal of Experimental Child Psychology, 77(3), 236-263.
  • Geary, D. C., & Hoard, M. K. (2003). Learning disabilities in basic mathematics - Deficits in memory and cognition. J. M. RoyerMathematical Cognition (pp. 93-115). PO Box 4967/Greenwich/CT 06831/USA: Information Age Publishing.
  • Geary, D. C., Hoard, M. K., ByrdCraven, J., Nugent, L., & Numtee, C. (2007). Cognitive mechanisms underlying achievement deficits in children with mathematical learning disability. Child Development, 78(4), 1343-1359.
  • Geary, D. C., Hoard, M. K., & Hamson, C. O. (1999). Numerical and arithmetical cognition: Patterns of functions and deficits in children at risk for a mathematical disability. Journal of Experimental Child Psychology, 74(3), 213-239.
  • Geary, D. C., & Huffman, K. J. (2002). Brain and cognitive evolution: Forms of modularity and functions of mind. Psychological Bulletin, 128(5), 667-698.
  • Geary, D. C., Liu, F., Chen, G. P., Saults, S. J., & Hoard, M. K. (1999). Contributions of computational fluency to cross-national differences in arithmetical reasoning abilities. Journal of Educational Psychology, 91(4), 716-719.
  • Geary, D. C., Saults, S. J., Liu, F., & Hoard, M. K. (2000). Sex differences in spatial cognition, computational fluency, and arithmetical reasoning. Journal of Experimental Child Psychology, 77(4), 337-353.
  • Geary, D. C., & Widaman, K. F. (1992). Numerical cognition: On the convergence of componential and psychometric models. Intelligence, 16, 47-80.
  • Geary, D. C., Liu, F., Chen, G.-P., Saults, S. J., & Hoard, M. K. (1999). Contributions of Computational Fluency to Cross-National Differences in Arithmetical Reasoning Abilities. Journal of Educational Psychology, 91(4), 716-719.
  • Geary, D. C., & Widaman, K. F. (1992). Numerical cognition: On the convergence of componential and psychometric models. Intelligence, 16(1), 47-80.
  • Trull, T. J., & Geary, D. C. (1997). Comparison of the big-five factor structure across samples of Chinese and American adults. Journal of Personality Assessment, 69(2), 324-341.
  • Widaman, K. F., Gibbs, K. W., & Geary, D. C. (1987). Structure of adaptive behavior: I. Replication across fourteen samples of nonprofoundly mentally retarded people. American Journal of Mental Deficiency, 91(4), 348-360.

CHC intelligence theory tipping point: It has come

[Double click on image to enlarge]

In April 2005, upon returning from the annual NASP (National Association of School Psychologists) convention, I concluded (in a blog post) that sometime during the past 5 years the CHC intelligence theory "tipping point" had occurred, and the CHC intelligence test bandwagon had gathered full steam. Before reading further, I would recommend reading that original post for background information and important links (esp. the link to the historical information I've written about the evolution of CHC theory).

To satisfy my curiosity I decided to gather some informal data...namely, the tracking of select terms in the body of messages on the NASP listserv. I wanted to see if there was any change in the usage of CHC-related terms over time. So...what did I do?

I went to the NASP listserv and used a Yahoo Groups feature that allowed me to search the body of all archived messages for key terms. I did this for different years. The terms I searched where Gf-Gc (what CHC theory originally was referred to prior to the publication of the WJ III; see prior original post for important link to historical background information), CHC, and WJ (Woodcock-Johnson). At the top of this post is a graph of the results.

From the figure I've concluded that the CHC tipping point, at least within the NASP community, occurred sometime between 2001 and 2003. The publication of the WJ III in 2001 is important as it was the first intelligence battery organized as per CHC theory (note - the1989 WJ-R was organized as per Cattell-Horn Gf-Gc theory). [Read the previously referenced historical background information regarding the role of the WJ-R and WJ III in the infusion of Gf-Gc and CHC theory into applied intellectual assessment - click on my original post to find this info]. As one can see, their was a huge amount of discussion of the WJ III went it hit the streets....volume that has continued for a number of years.

What I find particularly interesting is the replacement of references to Gf-Gc by CHC starting in the same year....2001. Notice the increase in CHC references from 2001 thru 2003 with a concurrent decrease in the use of the terms Gf-Gc. I would conclude, largely based on my personal knowledge of the history of the origin of the term "CHC" [again, read the historical information I've provided], that the publication of the WJ III was the primary event(as well as the increasing interest in CHC-organized cross-battery assessments) that resulted in the infusion of CHC theory into school psychology, as evidenced by a change in the language used by school psychologists on their general purpose listserv.

Since 2003 there has been a general decrease in the use of the CHC in NASP listserv messages. Does this mean that the interest in the theory has peaked? I think not. I've data to support this conclusion.

The NASP listserv is a general purpose topic listserv. Intellectual assessment/theory topics are only a small part of the collective message threads. I would advance the hypothesis that CHC theory continues to increase in the communications of psychologists. Upon what do I base this observation? I base this conclusion on the membership figures for the special-purpose CHC listserv that I started.

If you click here you will see a graph of the cumulative membership of the CHC list, a list that I started in order to give folks interested in CHC theory/assessment issues a place to talk about them in-depth.....and to also save the NASP listserv from such focused discussions (as all members may not be interested). As you can see from the membership numbers of the CHC list, membership is growing at a nearly constant linear rate from 2003 to 2006 [note - current membership is at 956 and should reach 1000 relatively soon].

I conclude that the infusion of CHC theory into school psychology, which reached a tipping point sometime between 2001 and 2003, continues at a very steady rate, as evidenced by the increasing membership of the CHC list, as well as other objective indicators (namely, revision of other intelligence batteries to provide CHC interpretive frameworks....SB5, KABC-II, DAS-II...as well as continued interest in CHC-organized cross-battery assesment).

Comments, thoughts, disagreements, etc. are welcome. Either post them here via the "comment" feature or share at the CHC listserv.


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Thursday, October 18, 2007

WISC-IV web meta-search link posted

I've added my 2nd IQ's Corner web meta-search link to the appropriate section of this blog (scroll down left side of blog to the "Meta-web searches" section). The topic is the Wechsler Intelligence Scale for Children--Fourth Edition (WISC-IV). Why would I do this, given my authorship of the WISC-IV's major competitor (WJ III) and my strong support for CHC theory, which the WISC-IV is not formally grounded in?

Simple. Any post that mentions this instrument generates traffic to my site...and the more people that come and "find a home" at IQ's Corner....the greater the chances more professionals will learn and improve their intelligence assessment practices.

Stay tunned. Other tests, concepts, ideas, topics, etc. will be similarly searched and added to the Meta-web search section (and routinely updated as needed) on a regular basis. Check back frequently.


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Wednesday, October 17, 2007

Executive functions highly genetic?

Thanks to Chris C at DI blog for the very interesting post about a new study that suggests that executive functions may have a strong genetic (heritable) component.

Blame your bad planning and impulse control on your parents ? Hmmmmmmmmmmm


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Psychology book nook reviews 10-17-07


A new issue of PsycCRITIQUES is available online.



October 17, 2007
Volume 52, Issue 42


Book Reviews
1. The Scope of Social Psychology: Theory and Applications
Authors: Miles Hewstone, Henk A. W. Schut, John B. F. De Wit, Kees van den Bos, and Margaret S. Stroebe (Eds.)
Reviewer: Luciano L'Abate

2. Evolutionary Perspectives on Environmental Problems
Authors: Dustin J. Penn and Iver Mysterud (Eds.)
Reviewer: Harry Heft

3. Co-Occurring Substance Abuse and Mental Disorders: A Practitioner's Guide
Author: John Smith
Reviewers: Alejandra Suarez and Douglas M. Kerr

4. Psychotropic Drug Prescriber's Survival Guide: Ethical Mental Health Treatment in the Age of Big Pharma
Authors: Steven L. Dubovsky and Amelia N. Dubovsky
Reviewer: Lisa J. Cohen

5. Overcoming Pathological Gambling: Therapist Guide
Authors: Robert Ladouceur and Stella Lachance
Reviewers: Mark S. Gold and Christopher J. Hammond

Overcoming Your Pathological Gambling: Workbook
Authors: Robert Ladouceur and Stella Lachance
Reviewers: Mark S. Gold and Christopher J. Hammond

6. The Dream Experience: A Systematic Exploration
Author: Milton Kramer
Reviewers: Mike Knight and James Vaughn

7. Buried in Treasures: Help for Compulsive Acquiring, Saving, and Hoarding
Authors: David F. Tolin, Randy O. Frost, and Gail Steketee
Reviewer: Susan H. Houston

8. Gay Conservatives: Group Consciousness and Assimilation
Author: Kenneth W. Cimino
Reviewer: Edward J. Tejirian

9. New Developments in Autism: The Future Is Today
Authors: Juan Martos Pérez, Pedro M. González, María Llorente Comí, and Carmen Nieto (Eds.)
Reviewer: Donald P. Oswald

10. The New Rational Therapy: Thinking Your Way to Serenity, Success, and Profound Happiness
Author: Elliot D. Cohen
Reviewer: Sara Dettinger Martino

11. Race, Gender, and Punishment: From Colonialism to the War on Terror
Authors: Mary Bosworth and Jeanne Flavin (Eds.)
Reviewer: Jesus (Jesse) Aros

12. The Methamphetamine Crisis: Strategies to Save Addicts, Families, and Communities
Author: Herbert C. Covey (Ed.)
Reviewer: Itai Danovitch

13. Communication Technology and Social Change: Theory and Implications
Authors: Carolyn A. Lin and David J. Atkin (Eds.)
Reviewer: Moshe Landsman

14. Psychotic Symptoms in Children and Adolescents: Assessment, Differential Diagnosis, and Treatment
Author: Claudio Cepeda
Reviewer: Timothy A. Sisemore

15. Primal Healing: Access the Incredible Power of Feelings to Improve Your Health
Author: Arthur Janov
Reviewer: Cindy Ycaza Stroschein

16. Acceleration for Gifted Learners, K–5
Authors: Joan Franklin Smutny, Sally Y. Walker, and Elizabeth A. Meckstroth
Reviewer: Janice E. Jones

Video Review
17. Integrative Family Therapy
with Jay Lebow
Reviewers: David S. Hargrove and Elizabeth M. Malone

Film Review
18. The Departed
Director: Martin Scorsese
Reviewer: Stephen P. Hampe

CHC intelligence theory meta-web search 10-17-07

I'm hoping to start yet another new feature at IQ's Corner - meta-web topic searches.

For a number of years I've been using the meta-search software program Copernic Agent Why?

Because it searches multiple search engines in a single search, allows me to save each search profile, and then I can routinely update the search to see if new information "pops up." As described at the CA web page:
  • Copernic Agent Basic gives you the ability to cover more of the Web and to get relevant, high quality results from more than 90 search engines grouped into categories. From a single query, Copernic Agent Basic gives you better search engine results by consulting multiple search engines at once, combining their results, removing duplicates and keeping only the very best of the information gathered from queried search engines.
I've just completed my "CHC theory" meta-search. I've saved the result--you can view it by clicking here. I hope to routinely update this CHC theory search, as well as add additional topic searches, as time goes by. I've added a new section to IQ's Corner (Meta-web searches - see left side of blog). Hopefully this will allow IQ's Corner readers to stay current re: the pulse of the web as it relates to key intelligence theory and test topics.

Readers are encouraged to send me suggested search topics either via the comment feature at this blog or through email (iap@earthlink.net)

Enjoy

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CHC theory now in Wikipedia

This morning I noticed that the CHC (Cattell-Horn-Carroll) Theory of intelligence is now an official entry in Wikipedia. Yet another indicator that the CHC tipping point has been reached. Currently it is not a large entry.

How about some CHC folks taking time to learn to edit in Wikipedia with the goal to build this entry into something more substantive.


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Saturday, October 13, 2007

Welcome Clocktower Hill Research & Publishing

Welcome Clocktower Hill Research and Publishing group! They have taken advantage of the great (cheap) advertising rates at IQ's Corner and now have an ad on this humble blog. See the ad on the left side of the blog page.

On a personal note, I've known Ron McGhee (one of the founders of this group) for a long time Ron is a great guy and I've always enjoyed his thoughts, writing and productivity. You can visit their site either by using the link above, or by clicking on their ad image.

Check out their site and psychoeducational assessment products. Below is a "blurb" re: their business (lifted from there web page).

  • Clocktower Hill Research and Publishing Group LLC was founded in 2003 as a research organization and developer and publisher of high quality assessment and resource materials for psychology, education, speech pathology, early childhood intervention, and occupational and physical therapy.

This now makes two psychological assessment publishers with ads at this blog (PAR being the other). Where are the big boys/girls of assessment (Psych Corp; Pearson AGS; Riverside; ProEd; etc.)? Get some great ad space while it is still available

[Note...as I've mentioned before, the placement of an ad at this blog does not imply a direct endorsement of any product or company. It is just a way for me, the blog dictator, to try make some pocket "ching" to pay for his caffeine addiction - Also note that ad rates will likely be going up at the end of this year :)]




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Thursday, October 11, 2007

Garruto responds to "factor analysis of IQ tests"

John Garruto, a member of IQ's Corner Virtual Community of Scholars group was weighed in on the Frazier & Youngstrom 2007 Intelligence article listed below (click here for prior posts re: this article). John's comments speak for themselves. Thanks John

Frazier, T.W. & Youngstrom, E.A. (2007). Historical increase in the number of factors measured by commercial tests of cognitive ability: Are we overfactoring? Intelligence, 35, 169-182. [article can be viewed at link at "prior post" link above]


Abstract
  • A historical increase in the number of factors purportedly measured by commercial tests of cognitive ability may result from four distinct pressures including: increasingly complex models of intelligence, test publishers' desires to provide clinically useful assessment instruments with greater interpretive value, test publishers' desires to include minor factors that may be of interest to researchers (but are not clinically useful), and liberal statistical criteria for determining the factor structure of tests. The present study examined the number of factors measured by several historically relevant and currently employed commercial tests of cognitive abilities using statistical criteria derived from principal components analyses, and exploratory and confirmatory factor analyses. Two infrequently used statistical criteria,that have been shown to accurately recover the number of factors in a data set, Horn's parallel analysis (HPA) and Minimum Average Partial (MAP) analysis, served as gold-standard criteria. As expected, there were significant increases over time in the number of factors purportedly measured by cognitive ability tests (r=.56, p=.030). Results also indicated significant recent increases in the overfactoring of cognitive ability tests. Developers of future cognitive assessment batteries may wish to increase the lengths of the batteries in order to more adequately measure additional factors. Alternatively, clinicians interested in briefer assessment strategies may benefit from short batteries that reliably assess general intellectual ability.
Garruto comments

As I was catching up on my NASP listserv digest, I saw a responsible practitioner query the group about how she could brush up on interpretation with her new WJ-III kit. I noted a variety of excellent responses. One really caught my eye where the poster indicated, “Read this article.” I began to think to myself, “I wonder what this article could add incrementally to this examiner’s skills?”

So I took the time to read the article and I must say that I found this article quite helpful. It will serve me well when I need scratch paper to write a phone number or perhaps as reading material when I am suffering from insomnia. On a more serious note, however, I did not find a great deal of utility for the applied practitioner. Furthermore, the article did not in the slightest way abet the poster with her query. I can only surmise the poster had made his recommendation to voice a possible disdain toward either the WJ-III or batteries that present with multiple factors.

Nevertheless, I will do my best to offer a summary and my perspective. However, individuals with a greater degree of statistical acumen will probably be able to comment more on its empirical support. The authors reviewed a variety of cognitive ability instruments and have noted that the number of factors measured by an individual ability test has outpaced the number of subtests/length of administration of these batteries. The authors identify the various factor analysis methods that have been used, citing certain methods have enjoyed popular use in recent history (including Cattell’s scree method, Kaiser’s criterion, and chi square method.) Furthermore, the authors cite two little used methods for identifying factors which included the minimum average partial (MAP) analysis and Horn’s Parallel Analysis (HPA)).

The authors did do a nice job of differentiating exploratory factor analysis (principal components analysis) and confirmatory factor analysis. For the lay reader, factors tend to be latent variables believed to be measured by observed variables (for example-the observed subtest of block design is believed to measure a latent variable of visualization). Exploratory factor analysis is a technique where certain skills tend to cluster or “hang” together and the commonality of the tasks imposed by the observed measures would lead to a factor naming. Confirmatory factor analysis, on the other hand, specifies the model beforehand and confirmation can be done via a goodness of fit (how well do our observed variables fit our specified model?)

I am not going to go into a lengthy discourse on statistics. In short, the authors indicate that test developers have been using factor analytic methods that have led to an over-identification of factors. The authors espouse using other techniques (such as MAP and HPA) in order to identify the number of factors likely at play for a given instrument. The findings of the authors is that using MAP or HPA, the number of factors should never exceed three (and that was just the HPA analysis of the WJ-III-the most complex instrument out there-all others recommended a 2 or 1 factor solution.) The conclusion of the authors is that we are over-factoring our tests and therefore we either need to make the tests longer (which the authors counter with a cost-prohibitive notion) or start reducing our factors.

I am going to leave it to the test developers and statisticians to comment on the merit of the statistics. Instead, I am going to provide the perspective of an applied practitioner. I have been using the WJ-III since its publication. Although I have had some concerns with this test-it always remains a staple of my assessment battery because of the breadth of the interpretable results. The WJ-III does have a three-factor solution, but it is then parsed further into a seven-factor solution if you give the extended battery. Namely, that (the three factor solution) is verbal ability, thinking ability, and cognitive efficiency. As a practitioner, these constructs help somewhat-but what does that really gain for me in understanding the various skills of a child? Sure I can look at verbal ability as just that, thinking ability as intentional cognitive processing, and cognitive efficiency as how effectively we manage our information, but what does that say about a child in terms of their need? Even more important, when a child presents with very solid short-term memory but very poor processing speed (yielding an average cognitive efficiency score), how does that factor help me? Even more important, how does this limited framework help the student?

The ongoing issues with subtest/profile analysis are well understood, particularly with regard to reliability issues. However, to intentionally blunt our knives seems counterproductive-particularly since the research has already panned out many of these factors. Furthermore, some subtests that are not figured into either factor because of mixed loadings can be very valuable. One subtest I am thinking of is Rapid Picture Naming. In my experience, I cannot tell you the amount of times I have looked at a child with a reading problem and that child completely bombed RPN. However, it’s a very mixed measure-there is still ongoing debate as to whether it’s a long-term storage and retrieval task (due to naming ability as a narrow ability) or processing speed task (given the speed at which one must name the tasks.)

On a final note…let’s look back to another test-the WISC-III. The WISC-III had both a two and a four-factor solution-yes it had the verbal and performance IQ. I also remember reading (I think) that Picture Arrangement subtest that seemed to load on both verbal and performance factors (just a bit stronger for performance). Frazier & Youngstrom discuss how many of our tests should have more than two subtests to measure a factor (p. 179). They also spend a good part of their article talking about the costs of lengthier assessments (p. 180). I can think of no greater waste of time and money than to measure a construct four times (ala crystallized intelligence on the WISC-III) so I can be really sure my factor is strong. Nevertheless-I will keep this article at the ready…I have three phone calls to return tomorrow.

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Wednesday, October 10, 2007

Metronome training improves reading achievement

This is a cross-post from IQ's Corner sister blog - the IQ Brain Clock re: a new journal publication that demonstrated the positive effects of a brain-based metronome training program on reading achievement. Check it out.

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Factor analysis of IQ tests: Too many factors?

This week, over on the NASP listserv, there has been a brief exchange re: the over-factoring of intelligence tests. It started when Dr. Gary Canivez referred to a recent article in the journal Intelligence (Frazier & Youngstrom, 2007). Dr. Canivez wrote:
  • You may also want to read the article by Frazier and Youngstrom (2007) on the issue of overfactoring in cognitive assessment instruments published in the journal Intelligence. Other issues related to how much variability is related to the highest order dimension (g) and what variability remains in lower order dimensions (second strata factors) also impacts interpretability of the scores.
I had previously commented ("Are contemporary IQ tests being overfactored") on this article (when "in press") at this blog, and won't repeat my thoughts here. The Frazier and Young abstract is below
  • A historical increase in the number of factors purportedly measured by commercial tests of cognitive ability may result from four distinct pressures including: increasingly complex models of intelligence, test publishers' desires to provide clinically useful assessment instruments with greater interpretive value, test publishers' desires to includeminor factors thatmay be of interest to researchers (but are not clinically useful), and liberal statistical criteria for determining the factor structure of tests. The present study examined the number of factors measured by several historically relevant and currently employed commercial tests of cognitive abilities using statistical criteria derived from principal components analyses, and exploratory and confirmatory factor analyses. Two infrequently used statistical criteria, that have been shown to accurately recover the number of factors in a data set, Horn's parallel analysis (HPA) and Minimum Average Partial (MAP) analysis, served as gold-standard criteria. As expected, there were significant increases over time in the number of factors purportedly measured by cognitive ability tests (r=.56, p=.030). Results also indicated significant recent increases in the overfactoring of cognitive ability tests. Developers of future cognitive assessment batteries may wish to increase the lengths of the batteries in order to more adequately measure additional factors. Alternatively, clinicians interested in briefer assessment strategies may benefit from short batteries that reliably assess general intellectual ability.
In an interesting response, Dr. Joel Schneider provided the following to chew on:

  • Gary, The paper you reference suggests that cognitive tests have "overfactored" their data, meaning they have extracted more factors than were really there in the data. It singles out the WJ-R and WJ-III as outliers (i.e., WJ batteries are REALLY overfactored). I found their conclusions hard to believe so I played with some simulated data using SPSS to see if I could make a simulated "WJ-III" dataset with 7 broad factor structures plus a g-factor uniting all the scores. Each subtest score was computed like this:

    Subtest = g + BroadFactor + error

    Each subtest was assigned to the broad factor it was designed to load
    on. Each source of variance was normally distributed.

    By systematically changing the variance of the g and broad factors, I
    was able to look at how different factor extraction rules performed
    under several combinations of g and broad factor sizes.

    I found that the presence of even a moderately-sized g-factor caused all
    of the factor extraction rules to underestimate the true number of
    factors (7 correlated factors in this case).

    It seems that under many plausible conditions WJ-III-like data will have
    more factors than detected by popular factor extraction rules. Thus, I
    think that this paper overstates its case.

    Here is my SPSS syntax. Create a few thousand cases and then play with
    the gCoefficient and FactorCoefficient variables (0 to 2 is a good range).

    COMPUTE gCoefficient = 1.5 .
    COMPUTE FactorCoefficient = 1.0.
    COMPUTE g = RV.NORMAL(0,
    1) .
    COMPUTE Gc = RV.NORMAL(0,
    1) .
    COMPUTE Gf = RV.NORMAL(0,
    1) .
    COMPUTE Gsm = RV.NORMAL(0,
    1) .
    COMPUTE Gs = RV.NORMAL(0,
    1) .
    COMPUTE Ga = RV.NORMAL(0,
    1) .
    COMPUTE Glr = RV.NORMAL(0,
    1) .
    COMPUTE Gv = RV.NORMAL(0,
    1) .
    EXECUTE .
    COMPUTE VC = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Gc .
    COMPUTE GI = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Gc .
    COMPUTE CF = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Gf .
    COMPUTE AS = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Gf .
    COMPUTE P = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Gf .
    COMPUTE VAL = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Glr .
    COMPUTE RF = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Glr .
    COMPUTE RPN = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Glr .
    COMPUTE NR = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Gsm .
    COMPUTE MW = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Gsm .
    COMPUTE AWM = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Gsm .
    COMPUTE VM = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Gs .
    COMPUTE DS = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Gs .
    COMPUTE PC = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Gs .
    COMPUTE SB = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Ga .
    COMPUTE AA = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Ga .
    COMPUTE IW = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Ga .
    COMPUTE SR = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Gv .
    COMPUTE PR = RV.NORMAL(0,
    1) + gCoefficient * g + FactorCoefficient * Gv .
    EXECUTE .
    FACTOR
    /VARIABLES VC GI CF AS P VAL RF RPN NR MW AWM VM DS PC SB AA IW SR PR
    /MISSING LISTWISE
    /ANALYSIS VC GI CF AS P VAL RF RPN NR MW AWM VM DS PC SB AA IW SR PR
    /PRINT INITIAL EXTRACTION ROTATION
    /FORMAT SORT BLANK(.10)
    /PLOT EIGEN
    /CRITERIA MINEIGEN(1) ITERATE(25)
    /EXTRACTION PAF
    /CRITERIA ITERATE(25)
    /ROTATION PROMAX(4)
    /METHOD=CORRELATION .

All of this "this factor analysis is better than that factor analysis" reminds me of a chapter written a long time ago by Doug Detterman (current and long-standing editor of the journal Intelligence---sorry...I can't recall the reference or the exact quotes...I'm going from long-term memory on this one) in some book on individual differences and intelligence that I read very early in my psychometric carrier. It was a chapter dealing with the laws of individual differences research. One of the laws had to do with factor analysis. In my own words---"if you put two factor analysis methodologists in the same room and an argument will break out....there will be no agreement on the number of factors to extract, the proper rotation method to use, and the interpretation of the factors."

So true! My only current comment is that having personally learned some of my most important lessons re: factor analysis from the likes of John Horn, John "Jack" Carroll, and Jack McArdle, there is as much "art" as there is "science" (specific factor extraction rules) to a proper factor analysis of intelligence tests.

Stay tunned. Dr. John Garruto has just sent me a practitioner perspective on this article. It will show up as a guest blog post later today or tomorrow.

Let the games begin.


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Tuesday, October 09, 2007

Psychology book nook reviews 10-09-07


A new issue of PsycCRITIQUES is available online.



October 10, 2007
Volume 52, Issue 41


Book Reviews
1. Assessing Hispanic Clients Using the MMPI-2 and MMPI-A
Authors: James N. Butcher, José Cabiya, Emilia Lucio, and Maria Garrido
Reviewers: Charles Golden and Maritza Figueroa

2. The Emerging Spatial Mind
Authors: Jodie M. Plumert and John P. Spencer (Eds.)
Reviewer: John S. Wodarski

3. Living in the Shadow of the Freud Family
Author: Sophie Freud
Reviewer: Jamieson Webster

4. Just War: Psychology and Terrorism
Author: Ron Roberts (Ed.)
Reviewer: Christopher J. Ferguson

5. Clinical Handbook of Co-Existing Mental Health and Drug and Alcohol Problems
Authors: Amanda Baker and Richard Velleman (Eds.)
Reviewer: Kristina Kays

6. Violent Video Game Effects on Children and Adolescents: Theory, Research, and Public Policy
Authors: Craig A. Anderson, Douglas A. Gentile, and Katherine E. Buckley
Reviewer: Sheila O'Brien Quinn

7. Social Communication
Author: Klaus Fiedler (Ed.)
Reviewer: Dana S. Dunn

8. Creativity: Theories and Themes: Research, Development, and Practice
Author: Mark A. Runco
Reviewer: F. Richard Ferraro

9. Children and Television: A Global Perspective
Author: Dafna Lemish
Reviewers: Fran C. Blumberg and Daniel P. Auld

10. Encyclopedia of Children, Adolescents, and the Media (Vols. 1 & 2)
Author: Jeffrey Jensen Arnett (Ed.)
Reviewer: Luciano L'Abate

11. Finding the Story Behind the Numbers: A Tool-Based Guide for Evaluating Educational Programs
Author: James Cox
Reviewer: Michael S. Matthews

12. Defusing the High-Conflict Divorce: A Treatment Guide for Working With Angry Couples
Authors: Bernard Gaulier, Judith Margerum, Jerome A. Price, and James Windell
Reviewer: Sally E. Thigpen

13. What Can I Do?: Ideas to Help Those Who Have Experienced Loss
Author: Barbara A. Glanz
Reviewer: John Edward Ruark

14. Coping With Infertility: Clinically Proven Ways of Managing the Emotional Roller Coaster
Authors: Negar Nicole Jacobs and William T. O'Donohue
Reviewer: Rosanna E. Guadagno

15. Handbook of Socialization: Theory and Research
Authors: Joan E. Grusec and Paul D. Hastings (Eds.)
Reviewer: Noach Milgram

16. Building Character: Strengthening the Heart of Good Leadership
Author: Gene Klann
Reviewer: Jay C. Thomas

17. From Staff Room to Classroom: A Guide for Planning and Coaching Professional Development
Authors: Robin Fogarty and Brian Pete
Reviewer: Joyce Adams

Film Review
18. The Wind That Shakes the Barley
Director: Ken Loach
Reviewer: Keith Oatley

IQ's Corner mind blogosphere headlines 10-09-07

All the news thats fit for IQ's Corner readers:

This is the 39th installment of IQs Corner Headlines from the Brain and Mind Blogsphere

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IQ's Corner: Recent literature of interest 10-08-07

This weeks recent literature of interest can be found by clicking here.


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Monday, October 08, 2007

Quantitive abilities - number sense

Someone recently sent me a nice article (click here to view) re: "number sense" that was previously published in the Journal of Learning Disabilities. According to the authors, a review of the diverse literature suggest that number sense "constitutes an awareness, intuition, recognition, knowledge, skill, ability, desire, feel, expectation, process, conceptual structure,or mental number line." I'd love to see some factor analysis research of comprehensive measures of number sense of good markers of Gf/Gq (RQ, KM, A3), to ascertain the narrow CHC domain(s) where these skills may lie. Does anyone have knowledge of any such research?

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Video games narrow visual-spatial (Gv) gender gap

Thanks to the ENL blog for drawing our attention to a new article in one of my favorite journals (Psychological Science) that suggests that playing today's video games may help reduce probably the most significant remaining gender difference in cognitive abilities...namely...visual-spatial abilities, especially visual rotation (Gv-SR; Vz)

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Saturday, October 06, 2007

Geekipedia @ Wired Magazine


[Double click on image to enlarge]

I'm just returning from a trip to Calgary, Canada. Prior to jumping on the plane I picked up a copy of Wired Magazine. I found a very cool extractable insert called Geekipedia. I must be a "geek" as I enjoyed reading the alphabetically listed definitions and explanations of important people, places, ideas and trends, primarily related to the internet and technology. I'm going to add this to my RSS feeds to keep up on new additions.

I particularly liked the visual-graphic for "neurologism"


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Tuesday, October 02, 2007

Monday, October 01, 2007

NSF 2007 Scientific Visualization Awards

If you love good visualization effects/images/procedures/etc., check out the 2007 NSF Scientific Visualization Awards. Very cool. Excellent Gv abilities.


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Memory special on CBC Radio

Thanks to Neuroethics and Law Blog for the FYI regarding a CBC radio program (Ideas) that is running a 5-part serios on memory this week.


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DIAL-3 factor study: Alternative CHC interpretation


[Double click on image to enlarge]

A recently published (Journal of School Psychology) article (Anthony et al., 2007; click here to view) reported an independent factor analysis of the Developmental Indicators for the Assessment of Learning--Third Edition (DIAL-3), an instrument designed for use with preschool-aged subjects. The sample was large (n=2000+) and both exploratory and confirmatory factor analysis methods were employed. I believe the study has merit given the sample size and reasonable factor methods employed. Below is the abstract:
  • To examine the convergent and discriminant validity of the scales on the Developmental Indicators for the Assessment of Learning—Third Edition [DIAL-3; Mardell-Czudnowski, C., and Goldenberg, D.S. (1998). Developmental indicators for the assessment of learning—third edition. Circle Pines, MN: American Guidance Service, Inc.], exploratory and confirmatory factor analyses were performed on randomly selected subsamples of 2012 children who attended Head Start. Exploratory factor analysis yielded three factors, labeled Verbal Ability, Nonverbal Ability, and Achievement, which collectively accounted for 56% of the variance in children's performances. Confirmatory factor analysis evaluated this empirically-derived model and the conceptually-derived model of the authors of the DIAL-3 in a separate subsample of children. Although neither model explained the data extremely well, the empirically-derived model characterized children's performances better than the conceptually-derived model, e.g., CFIs=.90 and .85, RMSEAs=.07 and .10, respectively. The discussion highlights an alternative conceptualization of the DIAL-3, potential uses of the factor scores, ideas for consideration during the next revision of the DIAL-3,and the need for additional validity research.
My two cents re: this study is not the number of factors extracted/confirmed (n=3), which seems reasonable, but the interpretation of the factors. The final accepted confirmatory model can be seen in the figure above.

Although the authors reference Carroll's (1993) seminal factor research synthesis and the work of Cattell-Horn to support their factor interpretations, the authors apparently did not attend to the entire work of Carroll. I concur that the factor they label as Verbal could also be interpreted to represent cyrstallized intelligence (Gc). However, the authors "Nonverbal" factor is incorrectly (IMHO) suggested to measure fluid intelligence (Gf). An inspection of the tests that load on the so-called Nonverbal factor reveals tests that are primarily measures of psychomotor abilities (e.g., copying, catching, jump/hop/skip, cutting, building with blocks, etc.). Although Carroll's model did not include psychomotor abilities, he did discuss them in a separate chapter in his book. Recently I wrote about the integration of the psychomotor broad ability domain (Gp) into CHC theory. If any "cognitive" abilities are measured in this so-called Nonverbal ability factor the logical choice would be Gv...not Gf.

Finally....I wish researchers would cease with the continued labeling of a "nonverbal" ability. As I've sermonized previously, there is not such cognitive ability as "nonverbal"....there are abilities (e.g., Gf, Gv, Glr) that can be assessed via nonverbal methods...but nonverbal does not exist as a distinct cognitive ability construct.


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