Reevaluating the Flynn effect, and the reversal: Temporal trends and measurement invariance in Norwegian armed forces intelligence scores

Reevaluating the Flynn effect, and the reversal: Temporal trends and measurement invariance in Norwegian armed forces intelligence scores

Open access PDF available from journal Intelligence…click here.

Abstract

Since 1954, the Norwegian Armed Forces have annually administered an unchanged general mental ability test to male cohorts, comprising figure matrices, word similarities, and mathematical reasoning tests. These stable and representative data have supported various claims about shifts in general mental ability (GMA) levels, notably the Flynn effect and its reversal, influencing extensive research linking these scores with health and other outcomes. This study examines whether observed temporal trends in scores reflect changes in latent intelligence or are confounded by evolving test characteristics and specific test-taking abilities in numerical reasoning, word comprehension, and figure matrices reasoning. Our findings, using multiple-group factor analysis and multiple indicator multiple cause (MIMIC) models, indicate that while there was a general upward trend in observed scores until 1993, this was predominantly driven by enhancements in the fluid intelligence task, specifically figure matrices reasoning. Notably, these gains do not uniformly translate to a rise in underlying GMA, suggesting the presence of domain-specific improvements and test characteristic changes over time. Conversely, the observed decline is primarily due to decreases in word comprehension and numerical reasoning tests, also reflecting specific abilities not attributable to changes in the latent GMA factor. Our findings further challenge the validity of claims that changes in the general factor drive the Flynn effect and its reversal. Furthermore, they caution against using these scores for longitudinal studies without accounting for changes in test characteristics.

Flynn Effect Reference Project has been updated 07-31-18

The Flynn Effect Reference Project document has just been updated.  It now includes 302 references.  Access can be found at this prior post (click here)

The Flynn Effect Reference Project document was been updated

The Flynn Effect Reference Project document has just been updated.  It now includes 296 references.  Access can be found at this prior post (click here)

Research Byte: What Causes the Anti-Flynn Effect? A Data Synthesis and Analysis of Predictors

Woodley of Menie, M. A., Peñaherrera-Aguirre, M., Fernandes, H. B. F., & Figueredo, A.-J. (2017). What Causes the Anti-Flynn Effect? A Data Synthesis and Analysis of Predictors. Evolutionary Behavioral Sciences. Advance online publication.

Article link.


Abstract

Anti-Flynn effects (i.e., secular declines in IQ) have been noted in a few countries. Much speculation exists about the causes of these trends; however, little progress has been made toward comprehensively testing these. A synthetic literature search yielded a total of 66 observations of secular IQ decline from 13 countries, with a combined sample size of 302,234 and study midyears spanning 87 years, from 1920.5 to 2007.5. Multilevel modeling (MLM) was used to examine the effect of study midyear, and (after controlling for this and other factors) hierarchical general linear modeling (GLM) was used to examine the following sequence of predictors: domain “g-ness” (a rank-order measure of g saturation) Index of Biological State (IBS; a measure of relaxed/reversed selection operating on g), per capita immigration, and the 2-way interactions IBS × g-ness and Immigration × g-ness. The MLM revealed that the anti-Flynn effect has strengthened in more recent years. Net of this, the GLM found that g-ness was a positive predictor; that is, less aggregately g-loaded measures exhibited bigger IQ declines; IBS was not a significant predictor; however immigration predicted the decline, indicating that high levels of immigration promote the anti-Flynn effect. Among the interactions there was a negative effect of the Immigration × g-ness interaction, indicating that immigration promotes IQ decline the most when the measure is higher in g-ness. The model accounted for 37.1% of the variance among the observations. (PsycINFO Database Record (c) 2017 APA, all rights reserved)


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Atkins-related Court decision: Cathey v Davis (2017, Texas)

For some reason I failed to post the most recent court decision this past May regarding Cathey, a case where the Flynn effect (norm obsolescence) is prominent. This decision can now be found here. The court granted Cathey a district court hearing to present evidence regarding the Flynn effect in his Atkins claim. Prior Cathey related posts can be found here.


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Flynn effect reference project

I had previously maintained a "Flynn effect archive" project at this blog.  In its prior form, it included a reference list and hyperlinks to almost all articles.  I have now found it necessary to remove all posts (and index tag terms) related to that project.  It's purpose has changed.

Originally the idea was to make available most the available research on the Flynn effect.  Over time I noticed (via the hit counter tracker) that fewer and fewer people were consulting it to obtain copies of articles.  The time necessary to maintain the archive, especially after I switched domain servers (which resulted in a ton of obsolete and broken hyperlinks), was not cost-effective.  Thus, that archive is no longer available.

In its place I am now  maintaining (and will update periodically) a simple working list of Flynn effect (aka, norm obsolescence) references.  The current version, dated 09-17-17, can be downloaded by clicking here.  It includes 291 302 (7-31-18) references.  I will refer to this as the Flynn Effect Reference Project.  I will update it on a regular basis, especially since it is now much easier to maintain.

The reference list should not be considered exhaustive of all possible published and unpublished research regarding the Flynn effect.  It is the best I can put together.  Any readers who locate missing articles, or new publications, should contact me via email (go to the MindHub and contact me via the contact info).  I will then add those to the next update.

Enjoy.

Sixth Circuit Court of Appeals rules against Flynn effect adjustment of IQ scores in Atkins death penalty cases: Black v Carpenter (2017)

A newly published 6th Circuit opinion (Black v Carpenter, 2017) rules against norm obsolescence (the Flynn effect) in the evaluation of IQ test scores in Atkins ID death penalty cases.  I obviously disagree with this decision as outlined in my 2015 chapter in the AAIDD "The Death Penalty and Intellectual Disability" (Polloway, 2015).

I have no further comment at this time as my expert opinion is clearly articulated in the AAIDD publication and I will continue my efforts to educate the courts.  This decision is at variance with the official positions of American Association on Intellectual and Developmental Disabilities (AAIDD) and the American Psychiatric Association (DSM-5), the two professional associations with official  guidance regarding  the diagnosis of ID. 

This looks like another issue that might need the attention of SCOTUS.

The following section is extracted from the complete ruling.


E. Implications of the Flynn Effect

There is good reason to have pause before retroactively adjusting IQ scores downward to offset the Flynn Effect. As we noted above, see n.1, supra, the Flynn Effect describes the apparent rise in IQ scores generated by a given IQ test as time elapses from the date of that specific test’s standardization. The reported increase is an average of approximately three points per decade, meaning that for an IQ test normed in 1995, an individual who took that test in 1995 and scored 100 would be expected to score 103 on that same test if taken in 2005, and would be expected to score 106 on that same test in 2015. This does not imply that the individual is “gaining intelligence”: after all, if the same individual, in 2015, took an IQ test that was normed in 2015, we would expect him to score 100, and we would consider him to be of the same “average” intelligence that he demonstrated when he scored 100 on the 1995-normed test in 1995. Rather, the Flynn Effect implies that the longer a test has been on the market after initially being normed, the higher (on average) an individual should perform, as compared with how that individual would perform on a more recently normed IQ test.

At first glance, of course, the Flynn Effect is troubling: if scoring 70 on an IQ test in 1995 would have been sufficient to avoid execution, then why shouldn’t a score of 76 on that same test administered in 2015 (which would produce a “Flynn-adjusted” score of 70) likewise suffice to avoid execution? Further, even if IQ tests were routinely restandardized every year or two to reset the mean score to 100, and even if old IQ tests were taken off the market so as to avoid the Flynn Effect “inflation” of scores that is visible when an IQ test continues to be administered long after its initial standardization, that would only mask, but not change, the fact that IQ scores are said to be rising.

Indeed, perhaps the most puzzling aspect of the Flynn Effect is that it is true. As Dr. Tassé states in his declaration, “[t]he so-called ‘Flynn Effect’ is NOT a theory. It is a wellestablished scientific fact that the US population is gaining an average of 3 full-scale IQ points per decade.” The implications of the Flynn Effect over a longer period of time are jarring: consider a cohort of individuals who, in 1917, took an IQ test that was normed in 1917 and received “normal” scores (say, 100, on average). If we could transport that same cohort of individuals to the present day, we would expect their average score today on an IQ test normed in 2017—a century later—to be thirty points lower: 70, making them mentally retarded, on average.

Alternatively, consider a cohort of individuals who, in 2017, took an IQ test that was normed in 2017 and received “normal” scores (of 100, on average). If we could transport that same cohort of individuals to a century ago, we would expect that their average score on a test normed in 1917 would be thirty points higher: 130, making them geniuses, on average.

It thus makes little sense to use Flynn-adjusted IQ scores to determine whether a criminal is sufficiently intellectually disabled to be exempt from the death penalty. After all, if Atkins stands for the proposition that someone with an IQ score of 70 or lower in 2002 (when Atkins was decided) is exempt from the death penalty, then the use of Flynn-adjusted IQ scores would conceivably lead to the conclusion that, within the next few decades, almost no one with borderline or merely below-average IQ scores should be executed, because their scores when adjusted downward to 2002 levels would be below 70. Indeed, the Supreme Court did not amplify just what moral or medical theory led to the highly general language that it used in Atkins when it prohibited the imposition of a death sentence for criminals who are “so impaired as to fall within the range of mentally retarded offenders about whom there is a national consensus,” 536 U.S. at 317. If Atkins had been a 1917 case, the majority of the population now living—if we were to apply downward adjustments to their IQ scores to offset the Flynn Effect from 1917 until now—would be too mentally retarded to be executed; and until the Supreme Court tells us that it is committed to making such downward adjustments, we decline to do so.

* * *

COLE, Chief Judge, concurring in the opinion except for Section II.E. I concur with the majority opinion except as to the section discussing the implications of the Flynn Effect. In holding that Black did not prove that he had significantly subaverage general intellectual functioning, we concluded that Black’s childhood IQ scores would be above 70 even if we adjusted those scores to account for both the SEM and the Flynn Effect. Accordingly, I would not address the question of whether we should apply a Flynn Effect adjustment in cases generally because it is unnecessary to the resolution of Black’s appeal. Regardless, courts, including our own in Black I, have regarded the Flynn Effect as an important consideration in determining who qualifies as intellectually disabled. See, e.g., Black v. Bell, 664 F.3d 81, 95–96 (6th Cir. 2011); Walker v. True, 399 F.3d 315, 322–23 (4th Cir. 2005).

New Wechsler Flynn Effect study by Weiss et al. (2015)

Click on image to enlarge

Flynn effect methodological issues: Special issue of the Journal of Intelligence

Special Issue "Methodological Advances in Understanding the Flynn Effect

Access to this open access journal can be found here. Quicklinks

• Special Issue Editors
• Special Issue Information
• Published Papers

A special issue of Journal of Intelligence (ISSN 2079-3200).

Deadline for manuscript submissions: closed (31 August 2015)

Special Issue Editor

Special Issue Information

Submission
Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.
Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Journal of Intelligence is an international peer-reviewed Open Access quarterly journal published by MDPI.
Please visit the Instructions for Authors page before submitting a manuscript. For the first couple of issues the Article Processing Charge (APC) will be waived for well-prepared manuscripts. English correction and/or formatting fees of 250 CHF (Swiss Francs) will be charged in certain cases for those articles accepted for publication that require extensive additional formatting and/or English corrections.

Guest Editor Prof. Dr. Joseph Lee Rodgers Department of Psychology and Human Development, Vanderbilt University, Peabody, 230 Appleton Place, Nashville, TN 37203, USA Website: http://www.vanderbilt.edu/psychological_sciences/bio/joe-rodgers

Another Flynn effect (norm obsolescence) meta-analysis

 (click on image to enlarge)

A second massive meta-analysis of the Flynn effect (norm obsolescence) was recently published (Pietschnig & Voraseck, 2015).  The study investigated different Flynn effect ability domain effects (by Gf, Gc, Gv), and other moderating variables.  However, the most important conclusion is that the authors conclude that the 3 IQ points per decade rule-of-thumb appears to be the best estimate of the FE on global IQ scores.  This conclusion is consistent with the Trahan et al. (2014) meta-analysis and the recent AAIDD recommendation.

AAIDD chapters on intellectual functioning and the Flynn effect - overdue post

(Click on image to enlarge)

It has been along time since I've been able to devote time to any of my three professional blogs.  I have been unbelievably busy with travel and professional presentations.  In fact, I have been so busy that I failed to feature two of my own recent Atkin's death penalty related book chapters that appeared in the new AAIDD book "Determining Intellectual Disability in the courts: Focus on capital cases." I have made these two chapters available via the MindHub web portal but do not believe I featured them at this blog (or at IQ's Corner).  One chapter deals with assessment of intellectual functioning issues and the other IQ test norm obsolescence (aka., the Flynn Effect).  The references (with links) are below.

McGrew, K. (2015a). Intellectual functioning. In Polloway, E. (Ed.), Determining Intellectual Disability in the courts: Focus on capital cases (pp. 85-111). Washington, DC: American Association on Intellectual and Developmental Disabilities.

McGrew, K. (2015b). Norm obsolescence: The Flynn Effect. In Polloway, E. (Ed.), Determining Intellectual Disability in the courts: Focus on capital cases (pp. 155-169). Washington, DC: American Association on Intellectual and Developmental Disabilities

The Flynn Effect in Atkins MR/ID Death Penalty Cases: Adjust or not to adjust--that is the question: A slide show

The Flynn Effect in Atkins MR/ID death penalty cases. Adjust or not to adjust--that is the question from Kevin McGrew

1949 WISC: What date(s) should be used to calculate the Flynn effect for historical IQ scores?

What date should be used when calculating the effect of norm obsolescence (aka, Flynn Effect) for old 1949 WISC scores?

I have seen psychological reports for three different Atkins MR/ID death penalty case reports and one social security report that referenced old WISC scores. The WISC was published in 1949 and was used well into the mid 1970's (when replaced by the WISC-R in 1974). The Flynn Effect (click here for posts linking to Flynn Effect Series of reports) was not yet a documented phenomenon, so examiners using the test late it it's life cycle were often not aware of the potential for a massive Flynn effect. At the end of it's life cycle WISC results were often interpreted on the basis of norms that were 20-25 years out of date! This is the worst case scenario for the Flynn Effect I have seen in old psychological reports.

There is some debate on which date for any IQ test should be used to estimate the Flynn Effect. The date of publication or the median date of the years during which the norm data was collected. I believe the consensus is the later.

But, when one turns to the WISC manual, it makes no mention of the years spanned during the norming. Thus, I made a request for information to a number of professional listservs and a number of people directed me to Flynn's (2006) "Tethering the Elephant" article. There is a footnote in that table that provides a lead.

Note. All dates assigned to tests refer to the date at which the test was normed. This is what is relevant, of course, not the date when the test was published. Another date that practitioners might like to have is that for the norming of the WISC: from 1947 to 1948.

Alan Kaufman also communicated with me privately (personal communication, 9-23-11) regarding my question. He worked with David Wechsler on the the WISC-R. He said that during that time the date of 1947 was almost always mentioned during their work, but he never did see concrete proof.

Finally, a member of a neuropsych. listserv sent me a 1950 smoking gun journal article authored by staff from Psychological Corporation. The article was a more in-depth description of the WISC standardization. Although only mentioned briefly in one sentence on p. 102, the dates 1947-1948 are mentioned as the period of the data collection.

Thus, when faced with historical records with old WISC scores, especially those where the effect of norm obsolescence on the scores is dramatic, the best estimate to use for calculating the Flynn Effect is 1947 to 1948. I would tend to think that given the publication and production processes at the time that most of the data was collected during 1947 as many 1948 activities were likely involved in printing and production. But, to be safe, I would suggest examiners use both 1947 and 1948 and then round to the average estimate. One year typically does not make a huge difference.

Thanks to all who sent me tips and the article. The internet, and many professional listservs, are awesome sources of information.

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Kevin McGrew APA Flynn effect in Atkins MR/ID cases complete handouts--as promised

Here is a copy of all my slides, in PDF format, that I promised at my APA Div 33 Atkins ID/MR symposium.


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The Flynn Effect report series: Is the Flynn Effect a Scientifically Accepted Fact? IAP AP101 Report #7

Another new IAP Applied Psychometrics 101 report (#7) is now available.  The report is the second in the Flynn Effect series, a series of brief reports that will define, explain and discuss the validity of the Flynn Effect (click here to access all prior FE related posts at the ICDP blog) and the issues surrounding the application of a FE "adjustment" for scores based on tests with date norms (norm obsolescence), particularly in the context of Atkins MR/ID capital punishment cases.  The abstract for the brief report is presented below.  The report can be accessed by clicking here.

Report # 1 (What is the Flynn Effect) can be found by clicking here.

This report is the second in a series of brief reports the will define, explain, and summarize the scholarly consensus regarding the validity of the Flynn Effect (FE). This brief report presents a summary of the majority of FE research (in tabular form of n=113 publications) which indicates (via a simple “vote tally” method) that despite no consensus regarding the possible causes of the FE, it is overwhelming recognized as a fact by the scientific community. The series will conclude with an evaluation of the question whether a professional consensus has emerged regarding the practice of adjusting dated IQ test scores for the Flynn Effect, an issue of increasing debate in Atkins MR/ID capital punishment hearings.

Technorati Tags: psychology, forensic psychology, forensic psychiatry, neuropsychology, intelligence, school psychology, psychometrics, educational psychology, IQ, IQ tests, IQ scores, adaptive behavior, adaptive functioning, intellectual disability, mental retardation, MR, ID, criminal psychology, criminal defense, criminal justice, ABA, American Bar Association, Atkins cases, death penalty, capital punishment, AAIDD, Atkins MR/ID listserv, ICDP blog, Flynn Effect, norm obselescence, Flynn Effect Series, IAP Applied Psychometric reports

The Flynn Effect report series: What is the Flynn Effect: IAP AP101 Report #6

A new IAP Applied Psychometrics 101 report (#6) is now available.  The report is the first in the Flynn Effect series, a series of brief reports that will define, explain and discuss the validity of the Flynn Effect (click here to access all prior FE related posts at the ICDP blog) and the issues surrounding the application of a FE "adjustment" for scores based on tests with date norms (norm obsolescence), particularly in the context of Atkins MR/ID capital punishment cases.  The abstract for the brief report is presented below.  The report can be accessed by clicking here.

Norm obsolescence is recognized in the intelligence testing literature as a potential source of error in global IQ scores.  Psychological standards and assessment books recommend that assessment professionals use tests with the most current norms to minimize the possibility of norm obsolescence spuriously raising an individual’s measured IQ.  This phenomenon is typically referred to as the Flynn Effect.  This report is the first in a series of brief reports the will define, explain, and summarize the scholarly consensus regarding the validity of the Flynn Effect.  The series will conclude with an evaluation of the question whether a professional consensus has emerged regarding the practice of adjusting dated IQ test scores for the Flynn Effect, an issue of increasing debate in Atkins MR/ID capital punishment hearings.

Technorati Tags: psychology, forensic psychology, forensic psychiatry, neuropsychology, intelligence, school psychology, psychometrics, educational psychology, IQ, IQ tests, IQ scores, adaptive behavior, adaptive functioning, intellectual disability, mental retardation, MR, ID, criminal psychology, criminal defense, criminal justice, ABA, American Bar Association, Atkins cases, death penalty, capital punishment, AAIDD, Atkins MR/ID listserv, ICDP blog, Flynn Effect, norm obselescence, Flynn Effect Series, IAP Applied Psychometric reports