Digit Span bombshell

You may recall that I wrote with great enthusiasm about the wonders of digit span, describing it as a modest bombshell. It is a true measure: every additional digit you can remember is of equal unit size to the next, a scaled score with a true zero. Few psychometric measures have that property (a ratio scale level of measurement in SS Steven’s terms), so the results are particularly informative about real abilities, not just abilities in relation to the rubber ruler of normative samples. If there are any differences, including group differences, on such a basic test, then it is likely they are real.

http://drjamesthompson.blogspot.co.uk/2014/03/digit-span-modest-little-bombshell.html

Then last November Gilles Gignac dropped another bombshell. He found that if you looked at total digit span scores since 1923 there was not a glimmer of improvement in this very basic ability. This cast enormous doubt on the Flynn effect being a real effect, rather than an artefact of re-standardisation procedures. Gignac noted that digits forwards and backwards were in opposite directions, but not significantly so.

http://drjamesthompson.blogspot.co.uk/2014/11/have-backward-digits-sunk-flynn.html

Later, I darkly suggested that another paper was in the offing, taking a different view of these data. Picture my pleasure when a barefoot messenger boy arrived at my humble cottage bringing a parchment missive with the unmistakeable seal of Woodley of Menie, the young inheritor of the great estate further North.

Young Woodley tells me that Gignac’s “substantial and impressive body of normative data on historical means of various measures of digit span covering the period from 1923 to 2008” reveals a hidden finding: the not-very-g-loaded digits forwards scores have gone up and the g-loaded digits backwards scores have gone down. This suggests that the fluffy forwards repetition task has benefitted from secular environmental gains, while the harder reversal task reveals the inner rotting core of a dysgenic society. Perturbed at these findings, I made sure that the messenger boy was kept outside, away from the under-maid, while I penned my reply.

Michael A.Woodley of Menie  and Heitor B.F. Fernandes (2015) Do opposing secular trends on backwards and forwards digit span evidence the co-occurrence model? A comment on Gignac (2015). Intelligence 50 (2015) 125–130

https://drive.google.com/file/d/0B3c4TxciNeJZSzlJT2tVZUVnZjA/view?usp=sharing

Woodley and Fernandes opine:  Gignac's (2015) observations are important as they add to the list of rarely considered cognitive measures the secular trends for which seem to defy the Flynn effect. These include inspection time, which, like digit span, seems to show no secular trends (Nettelbeck & Wilson, 2004), simple visual reaction time, which seems to show quite pronounced secular declines (Silverman, 2010; Woodley, Madison, & Charlton, 2014a; Woodley of Menie, te Nijenhuis, & Murphy, 2015; Woodley, te Nijenhuis, & Murphy, 2013b, 2014b) and also society-level indicators of cognitive capacity, such as per capita rates of macro-innovation and genius, which also indicate pronounced declines starting in the 19th century (Huebner, 2005; Murray, 2003; Simonton, 2013; Woodley, 2012; Woodley & Figueredo, 2013).

Woodley has proposed a co-occurrence model: losses in national IQ brought about by the higher fertility of the less intelligent exist at the same time as IQ gains brought about by more favourable social environments. “A rising tide raises all boats, but some are leaky”. More specifically, the dysgenic loss should be concentrated on g as dysgenic fertility and mutation load are biggest on more g-loaded subtests (Peach, Lyerly, & Reeve, 2014; Prokosch, Yeo & Miller, 2005; Woodley & Meisenberg, 2013a). Secular environmental IQ gains (i.e. Flynn effects) are concentrated on ability specific sources of performance variance (te Nijenhuis & van der Flier, 2013; Woodley, te Nijenhuis, Must, & Must, 2014c), thus narrow abilities should be increasing in parallel. Key to this is the observation that heritabilities rise with increasing g loading (Kan,Wicherts,Dolan,& van derMaas, 2013; Rushton & Jensen, 2010; te Nijenhuis, Kura, & Hur, 2014). Heritability may therefore mediate the effect of both dysgenic selection and related factors, such as mutation accumulation, and environmental improvements on IQ scores, concentrating the effects of the former on g and the latter on the specific variances of cognitive abilities.

Woodley and Fernandes have done a re-analysis of the forwards and backwards digit scores, using sample-size-weighted least squares regression. As befits his aristocratic origins, Woodley does not deign to make it clear what A and B stand for. In my role as interlocutor I can tell you that, for no particular reason, A = Backwards digits and B = Forwards digits. If only I had been consulted! Airliners have crashed due to such poor labelling, and operating table errors due to these baffling descriptions don’t bear thinking about.

 

In summary, digits forwards have increased somewhat, digits backwards have decreased. Woodley appears to have got another indicator of mild dysgenic trends.

Selecting the best scrap of paper I could find in the oaken desk, I acknowledged the kind communication of this intriguing finding, and bade Woodley of Menie a Happy Easter. I bestowed the same valediction on the messenger boy, plus the customary shilling, and sadly without the shilling, wish you the same.

ORIGINAL PAPER: How clever were the Victorians? A comment on Woodley et al. (2013) by Elijah L. Armstrong

Abstract: Woodley et al. (2013) cite declines in simple reaction time as evidence of dysgenesis. In this paper it is conceded that these declines are strong evidence for a dysgenic trend. However, declines in g cannot be inferred from reaction time declines alone.

Woodley et al. (2013) are quite correct that the existence of a secular decline in reaction time suggests dysgenesis. However, the secular decline in reaction time is probably a poor quantification, per se, of the exact dysgenesis rate. Woodley (2012) argues that the Flynn effect may be caused by increasing specialization in cognitive abilities. If specialization has truly increased, one would expect to see a secular decline in certain such abilities. These abilities are probably, for the most part, not measured on typical g-loaded tests (Lynn, 1998 gives the example of farming ability), but it is nevertheless to be expected that some g-loaded tests will show a secular decline. It may be responded that reaction time’s shared variance with g is wholly genetic (Woodley et al. cite Rijsdijk et al., 1998 on this matter) and therefore changes in specialization will have a minor impact. However, even if the environmental influences on reaction time are different from those on IQ, there may still be considerable environmental influences. Moreover, reaction time influences mortality rates (Deary & Der, 2005). Declining reaction time independent of g fits into Woodley’s (2012) life-history model because there would be less pressure to develop a mortality-mediating ability in a less environmentally harsh environment. It should be noted as well that even though simple reaction time shows little or no training effect (Kida et al., 2005), there may be other processes that decrease simple reaction time, such as imprinting (Armstrong & Woodley, under review).

While Woodley et al. extract declines in g from the declines in reaction time (given a .54 correlation), simply multiplying the decline in reaction time by the g-loading is not sufficient to establish a decline in g (cf. Dickens & Flynn, 2001 for discussion of a similar issue). Using a similar procedure on IQ tests for the Flynn effect would imply high g gains (say, if performance on a test with a g-loading of 0.8 has increased by a d of 1, this procedure would imply that g has increased by a d of 0.8). However, the Flynn effect is not on g (Woodley, 2011, 2012a, 2012b; te Nijenhuis & van der Flier, 2013).

A number of similar declines (approximately 1 SD since the Victorian era) on other highly g-loaded tests or abilities would corroborate Woodley et al.’s dysgenesis estimate. To the best of my knowledge, though, there are few tests that have shown a secular decline; the SATs have, but the population has grown increasingly representative (e.g., Williams and Ceci, 1997; Sailer, 2011a, 2012). Piagetian tasks show a decline (Shayer et al., 2007), and if the decline in g estimated from secular trends in Piagetian tasks is comparable to the decline in g estimated from secular trends, this would corroborate a 1 SD dysgenesis estimate. Likewise, if the decline in IQ among wealthy countries that are no longer experiencing the Flynn effect (e.g., Sundet et al., 2004) was similar to the decline measured using reaction time, Woodley et al.’s estimate would be validated.

Finally, it should be noted that a g decline of 1 SD is difficult to believe (cf. Charlton, 2013; Flynn, 1987; Guha, 2001 for discussion of a similar issue).[1] A community with average levels of g 1 SD higher than modern populations would be supermen. Ashkenazi Jews, who are a tremendously successful ethnic group, appear to have IQs around 110 (e.g., Cochran et al., 2005; Lynn, 2011; Sailer, 2011b). Hence even the most intellectually successful ethnic group would have IQs five points lower than the Victorians, if Woodley et al. are correct. This process of devolution is made quite incredible by the fact that it is hypothesized to have occurred in only 130 years (Cochran, 2012).

References

Armstrong, E., and Woodley, M. A. The rule-dependence model explains the commonalities between the Flynn effect and IQ gains via retesting. Under review.

Charlton, B. (2013). "Extraordinary claims require extraordinary evidence" - with respect to the claim of intelligence decline since Victorian times. Retrieved from http://charltonteaching.blogspot.com/2013/05/extraordinary-claims-require.html.

Cochran, G., et al. (2006). Natural history of Ashkenazi intelligence. Journal of Biosocial Science, 38, 659-693.

Cochran, G. (2012). The long and short of it. Retrieved from http://westhunt.wordpress.com/2012/11/04/the-long-and-short-of-it/.

Deary, I., and Der. G. (2005). Reaction time explains IQ’s association with death. Psychological Science, 16, 64-69.

Dickens, W., and Flynn, J. R. (2001). Heritability estimates versus large environmental effects: The IQ paradox resolved. Psychological Review, 108, 346-369.

Flynn, J. R. (1987). Massive IQ gains in 14 nations: What IQ tests really measure. Psychological Review, 101, 179-191.

Guha, S. (2001). A philosopher’s paradise––in inspired lunacy. Retrieved from http://www.amazon.com/review/R2ER6NZI1H2WJ/ref=cm_aya_cmt?ie=UTF8&ASIN=0631224262#wasThisHelpful.

Rijsdijk, F. V., et al. (1998). The genetic basis of the relation between speed-of-information-processing and IQ. Behavioural Brain Research, 95, 77-84.

Lynn, R. (1998). In support of the nutrition theory. In U. Neisser (Ed.), The rising curve: Long-term gains in IQ and related measures (pp. 207-215). Washington, D. C.: American Psychological Association.

Lynn, R. (2011). The Chosen People. Augusta, GA: Washington Summit Publishers.

Sailer, S. (2011a). SAT score changes by race since 1996. Retrieved from http://isteve.blogspot.com/2011/09/sat-score-changes-by-race-since-1996.html

Sailer, S. (2011b). Lynn on the Jews: Yes, it’s intelligence –– but there’s something else too. Retrieved from http://www.vdare.com/articles/lynn-on-the-jews-yes-it-s-intelligence-but-there-s-something-else-too.

Sailer, S. (2012). SAT and ACT: How hard are they scraping the bottom of the barrel and are they finding any diamonds in the rough? Retrieved from http://isteve.blogspot.com/2012/10/sat-and-act-how-hard-are-they-scraping.html

Shayer, M., et al. (2007). Thirty years on – a large anti-Flynn effect? The Piagetian test Volume & Heaviness norms 1975–2003. British Journal of Educational Psychology, 77, 25-41.

Sundet, J.M., et al. (2004). The end of the Flynn effect?
A study of secular trends in mean intelligence test scores of Norwegian conscripts during half a century. Intelligence, 32, 349-362.

te Nijenhuis, J., & van der Flier, H. (in press). Is the Flynn effect on g?: A meta-analysis. Intelligence.

Williams, W. M., and Ceci, S. J. (1997). Are Americans becoming more or less alike? Trends in race, class, and ability differences in intelligence. American Psychologist, 52, 1226-1235.

Woodley, M. A. (2011a). Heterosis doesn’t cause the Flynn effect: A critical examination of Mingroni (2007). Psychological Review, 118, 689-693.

Woodley, M. A. (2012a). The social and scientific temporal correlates of genotypic intelligence and the Flynn effect. Intelligence, 40, 189–204.

Woodley, M. A. (2012b). A life history model of the Lynn-Flynn effect. Personality

and Individual Differences, 53, 152–156.

Woodley, M.A., et al. (in press) Were the Victorians cleverer than us? The decline in general intelligence estimated from a meta-analysis of the slowing of simple reaction time. Intelligence.

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[1] Charlton’s discussion of this line of reasoning is critical.

Is young Woodley down for the count?

 

Things are looking bad for the young challenger Woodley, who came out of the te Nijenhuis and Murphy corner swinging his punches against World Champion Jim Flynn, claiming that, on the basis of Galton’s reaction time data, the lower classes have been breeding too much, casting us all into dysgenic stupidity. His paper “Were the Victorians brighter than us?” (plugged on this blog) got lots of press coverage and, according to the editor, became one of the most downloaded papers on the Intelligence website. No sooner had he landed his eugenic blows on the chin of environmental optimism than there was a heavy weight, four round, concerted counter attack.

When the bell rang for the second round, back into the ring climbed the redoubtable Mighty Champion Flynn, a grizzled New Zealand pugilist, mentored by the great Jensen himself, veteran of many hard slogs, who leads with the left but can also jab with the right, but is always a principled follower of the Marquis of Queensbury’s rules. He hammered Woodley thus: Woodley’s estimated dysgenic rate is three times larger than the theoretical rate on the basis of the negative correlation between IQ and number of siblings throughout the 20th century, making Woodley’s finding implausible. Secondly the absence of a Jensen effect on the Flynn effect is not prima facie evidence that g has been in decline. Thirdly, the secular trend towards declining genius does not evidence the dysgenic trend owing to subjectivity amongst ratings of genius. Fourthly there is substantial methods variance, rendering cross-study comparisons difficult to say the least.  Fifthly, despite the likely presence of dysgenic fertility in Australia during the period spanning 1981 to 2000, there is no decline in performance with respect to another elementary cognitive task (inspection time), which is problematic for the dysgenic interpretation of slowing reaction times.

Seeing the young challenger stunned by his solid punches, in a gracious concession just before the bell, Flynn did his own estimate of the dysgenic trend on Woodley’s data, admitting a smaller but evident 3 point decline overall.

For the third round the Australian Ted Nettlebeck, sun-bleached and hardened by the toil of 20 years of inspection time, jumped into the ring, to land these four Antipodean blows: Firstly, methods variance makes it difficult to compare studies. Secondly, the idea that antagonistic genetic and environmental forces can make intelligence trend in conflicting directions is flawed because the g loading of processing speed measures can only be established by correlating them with the same traditional measures of intelligence which show the Flynn effect. Thirdly, Nettlebeck argues that the decline in simple reaction times cannot constitute a decline in g because the principle causes are showing opposite secular gains. Fourthly, Nettelbeck also criticizes the assumption that simple RTs are associated with high heritability and that they are respectably g-loaded – arguing that both are required for the Woodley argument to work, but that neither is supported by the data.

For the fourth round, the experienced Silverman, a quieter fighter, with a good solid punch, and the original collector of historical reaction times enters the ring. These were his blows: the trend towards the secular lengthening of simple reaction times doesn’t hold when only the male cohorts are considered, in addition to the removal of the Galton datapoint. He contends that the presence of mixed-sex samples containing females (who have slower RT means than men on average) might have skewed the original Galtonian result. He adds that there are too few data points for Woodley to assume a linear relationship with slowing reaction time and year, which would be required to prove a dysgenic trend.

The fifth round brought in the formidable Russian Dodonov and Dodonova duo, an unusual husband and wife combination of legendary aggression, who think nothing of subjecting their own swaddling infant to a crash immersion in intelligence conferences, seeking precociously to add a third fighter to the team. As befits their energetic flurry of punches, they have even partly rebuilt Galton’s equipment to administer a final body blow: they contend that the studies lack comparability, and that controlling for this methods variance effectively obliterates the secular trend towards slowing RT speeds reported in both Silverman (2010) and Woodley et al. (2013). The error sources include stimulus onset delay, long and variable preparatory intervals and key pressure time, which inflate the latency of simple RT performance in more modern studies employing electronic rather than purely mechanical chronoscopes. Using a description of Galton’s pendulum chronoscope, they constructed a somewhat similar instrument, and found that the estimates produced are relatively free of sources of lag that seem to plague the more modern, electronic-instrument-based studies, such as key-pressure time. This is illustrated by direct comparison of the two author’s aggregate simple RT performance on both mechanical and electronic apparatuses – indicating a latency differential of approximately 30 ms favouring performance on the pendulum chronoscope in both cases. That puts puts the tin lid on it, surely? The pendulum method was faster than the contemporary electronic set up.

Te Nijenhuis and Murphy have been yelling encouragement, but the end of the fifth round the plucky Woodley is slumped on his corner stool, and there is only so much the duo can do with sticking plaster to repair their man’s battered countenance. Dutch pragmatism and Irish spirit have their limits. Quite frankly, Woodley’s choosing to box in his habitual long Edwardian jacket and gold pince-nez may not have been the best policy. Has it all been too much for him? Will he be able to stagger out for the sixth round?

The following paper has been submitted to Intelligence and is under review:

Woodley, te Nijenhuis, and Murphy “The Victorians were still quicker and cleverer than us: Responding to a quartet of critical commentaries.”

Whilst I cannot reveal the content until it has been accepted for publication, I can promise you horrific scenes of violence. If you are of nervous disposition, you should avert your eyes.

Woodley leads with an abstract

 

Handing over his long Edwardian frock coat and gold pince-nez to Heitor Fernandes and Aurelio José Figueredo, his Latin seconds,  Woodley bounded into the ring and opened the first round in traditional fashion, with a well managed and elegant abstract, which I replay for you below.

 

 

The Victorians were Still Cleverer than us: Expanding the Dysgenic Nexus

Michael A. Woodley¹, Heitor B. F. Fernandes², & Aurelio José Figueredo³

¹Center Leo Apostel for Interdisciplinary Research, VUB, Belgium.

²Departments of Psychology and Genetics, Federal University of Rio Grande do Sul, Brazil.

³Department of Psychology, University of Arizona, USA.

It is theorized that dysgenic effects and the Flynn effect co-occur, with the former concentrated on highly heritable g (Woodley & Meisenberg, 2013) and the latter on less-heritable non-g sources of IQ variance (te Nijenhuis & van der Flier, 2013). Evidence for this comes from the observation that 19^th century populations were more intellectually productive (Huebner, 2005; Murray, 2003; Woodley, 2012; Woodley & Figueredo, 2013), and also exhibited faster reaction times than modern ones (Woodley et al. 2013), suggesting that g has declined independently of any subsequent improvements that may have occurred with respect to narrower cognitive abilities. We conduct a new test of this model by examining historical changes in the frequencies of the utilization of words from the highly g-loaded WORDSUM test across 5.9 million texts spanning from 1850 to 2005. We find, consistent with predictions, that the item-level difficulties (δ parameters derived from Item Response Theory analysis) of these words predict the degree to which the words decline in use over time even when word obsolescence and temporal autocorrelation are explicitly controlled using Multi Level Modelling (the interaction of word difficulty with time negatively predicted word frequencies – b = -.09; semipartial r = -.09; the time variable was log transformed). When considered independently, predicted year-on-year word frequency trends furthermore revealed that the four high-difficulty (and presumably more g loaded) words trended negatively across time whereas the six low-difficult words exhibit no systematic changes in utilization with time. Given that the populations from which WORDSUM participant birth cohorts are sampled are known to have been in persistent dysgenic fertility since 1900 (Lynn & van Court, 2004; van Court & Bean, 1985) we interpret these trends as evidence that contributors to texts and their target audiences might have experienced dysgenic declines in general intelligence since the mid-19^th century. These new findings increase the breadth of the nomological net of historiometric, psychometric and evolutionary biological findings indicating persistent dysgenic declines in g amongst Western populations since the mid-19^th century.

 

In round 2 Woodley lays out his case in detail, which will begin after the one minute rest interval (which in publishing time  rather than boxing time means about a week or two).

Intelligence lost at 1.23 IQ points per decade

 

Michael Woodley of Menie spends much of his time tending his ancestral estate, pacing the linen-fold panelled rooms of the ancient house, warming his hands at the towering stone fireplace and meditating on the collapse of the aristocracy, the paucity of contemporary innovation and the lamentable and persistent downward drift of the national intellect. Now he sends me a barefoot runner with his latest manuscript, which I have read as the autumn mists creep across the Nadder valley, before penning this reply for the poor urchin to carry back to his master.

Young Woodley avers that, not only are we going to hell in a handcart, but we are doing so at a pace which he can predict with some accuracy (1.23 IQ points per decade), composed as it is of two dysgenic effects: the dull have been reproducing with greater fecundity than the bright (.39), and increasing paternal age has increased the rate of deleterious mutations (.84).

In the spirit of the age, and with an ever-present concern for your health and safety, those of you who are of nervous disposition or advancing paternal age should turn away, and listen to light classical music.

How fragile is our intellect? Estimating losses in general intelligence due to both selection and mutation accumulation. Michael A. Woodley of Menie. Personality and Individual Differences 75 (2015) 80–84

https://drive.google.com/file/d/0B3c4TxciNeJZN0I0NzAzVU0zeDQ/view?usp=sharing

General intelligence is an adaptation to solving evolutionarily novel and domain general fitness problems, i.e. problems which occur on an irregular rather than predictable basis throughout the course of evolution and which are complex, requiring the recruitment and coordination of large numbers of specialized mechanisms in solving them (Geary, 2005; MacDonald, 2013).

it has been argued that deleterious mutations exhibiting small effects accumulate within a population – persisting within genomes for long periods of time before substantially inhibiting fitness, thus giving rise to individual differences in general intelligence (g) and other potentially mutation-sensitive traits, such as health and physical attractiveness (Miller, 2000a,b; Penke, Denissen, & Miller, 2007).

The Breeder’s equation (Fisher, 1929) is frequently employed in studies of this kind:

R ¼ S _ h2

In this equation, S constitutes the size of the selection pressure operating on IQ transformed into a phenotypic change (i.e. the degree to which the trait will change over a generation assuming no biological regression to the mean, or perfect heritability). h2 represents the additive heritability of IQ. The product of these two terms gives us the expected responsiveness to selection, or R, which in terms of IQ is scaled as a change in ‘genotypic IQ’, or the degree to which the underlying genetic potential for a certain level of IQ should decline per generation (Lynn, 2011).

Woodley does a meta-analysis of 9 studies in the US and UK (simply for cultural similarity) to estimate this dysgenic effect on heritable g. This comes to an estimated decadal heritable g decline of 0.385 points.

It may be possible to crudely estimate the impact of mutation accumulation on g. Ideal for this purpose is the study of Kong et al. (2012) in which the numbers of de novo mutations in offspring were counted and correlated with the age of their fathers. Kong et al. found a strong linear relationship between the two (r = .97) amongst a sample of 78 Icelandic parent–child trios. They estimated an average increase in the offspring’s number of de novo mutations at 2.01 per year of paternal age. At 35 years of age, i.e. one familial generation (Kong et al., 2012), fathers are producing offspring with an average of 70 de novo mutations. Using this estimate, it is possible to determine the relationship between the increase in de novo mutation and IQ-loss as a function of paternal age.

These calculations are a little more complex, because they require re-examination of previous “corrections” for birth order. Perhaps there is a book to be written about the assumptions which underlie all statistical adjustments in psychology papers, to be called “The Correction of Corrections”.

The meta-analytic aggregate estimate of the loss in heritable g due to selection (estimated in Section 2 at q = .39 points per decade) can be combined with the loss expected from mutation accumulation, which was estimated at .84 points per decade. As the latter estimate was derived using structural equations modelling, error has been controlled, therefore the loss due to mutation accumulation is symmetric in terms of reliability and validity with respect to the meta-analytic loss due to selection.

The sum of the selection and mutation accumulation losses (i.e. the overall dysgenic loss) is therefore 1.23 points of heritable g per decade, or 4.31 points per familial generation. If the 95% confidence interval for the decline estimate due to mutation accumulation (the paternal age effect; i.e. 1.53–.14 points per decade) is generalized to the sum of both estimates, this yields upper and lower bound decline values ranging from 1.92 to .53 points per decade, or 6.72 to 1.86 points per familial generation.

One potential objection to the finding that g is declining by the amount claimed here stems from the Flynn effect, which is associated with an average increase in IQ of three points per decade (Flynn, 2009). The Flynn effect is however least pronounced on the most heritable and also g loaded IQ subtests (Rushton & Jensen, 2010; te Nijenhuis & van der Flier, 2013), which indicates that secular IQ gains occur at the level of less heritable and narrow abilities, rather than on g. Selection effects and the effects of mutation load on IQ are however more pronounced on the most g loaded subtests (Peach et al., 2014; Prokosch, Yeo, & Miller, 2005; Woodley & Meisenberg, 2013). On this basis dysgenic effects and the Flynn effect could co-occur – with dysgenics reducing the level of heritable g, and various environmental improvements raising narrow abilities simultaneously, via their effects on non-g variance. This hypothesis has been termed the co-occurrence model (Woodley & Figueredo, 2013).

So, there is a prompt and visible effect caused by the liberal use of fertilizer (environmental improvements) giving us a 3 IQ point gain, and a less visible and insidious worsening of seed quality (mutation and differential fertility) losing us 1.2 IQ points. All boats rise on the rising tide of affluence, but some are leaky.

Finally, Woodley links this finding to his work showing that reaction times are slowing up, which he sees as confirmation of the same dysgenic trend.

So, in reply to young Woodley, ever conscious that grim calculations of this sort might cause dismay to sensitive souls, I have placed another log on the fire, and sent him the cheerful and uplifting words of Walter Savage Landor:

I strove with none, for none was worth my strife.
Nature I loved and, next to Nature, Art:
I warm'd both hands before the fire of life;
It sinks, and I am ready to depart.

In the beginning was the Word

 

Words can be repeated easily, but are understood with more difficulty. The sense must be determined partly by context, and then the specific function of the word refined by closer examination of how it is used, and how it differs in meaning from other similarly functioning words. Listen, repeat, guess, venture a usage, test, refine, test, utilise. Search for meaning, not noise; reduce uncertainty rather than increase it. Concepts, not tropes.

Thus the word stores of individuals vary: not all people will be able to use precision instruments, or even see the need for them. 40,000 tools is a lot to carry in a brain. A passable job, rough and ready, can be achieved with 9,000. Vocabulary stores are good predictors of general ability, and their high storage cost must be worth it.

Looking across generations is harder. My brothers and I laughed at my grandmother for referring to a drinking glass as “a tumbler” and mocked her for insisting such vessels always be placed on a lace doily, so as to leave no ring marks on the dining table. Testing contemporaries on dated usages is unfair. Does that mean we cannot determine anything about the vocabularies of today compared with those of our grandparents?

I was pondering these weighty matters when once again the familiar urchin messenger boy arrived with yet another missive from the grand house of Woodley of Menie. I cannot be sure, but I think the miscreant boy calls on the under kitchen maid first, and only afterwards comes round to knock on the front door, which may account for his flushed countenance.

What Woodley and his dining companions Fernandes, Figueredo and Meisenberg have done is to tie together four disparate but crucially related aspects of vocabulary: the extent to which a word can be defined (intelligence loaded vocabulary test), the historical birth of the word (when it first shows up in dictionaries, which they call “word age”); levels of national literacy and the extent to which it is now used in written texts (Ngram usage measures 1850-2005). Crafty, this gang. Here are a few highlights before you look at the final corrections on the not yet finished proofs.

Michael A. Woodley of Menie, Heitor B. F. Fernandes, Aurelio José Figueredo and
Gerhard Meisenberg “By their words ye shall know them: Evidence of genetic selection against general intelligence and concurrent environmental enrichment in
vocabulary usage since the mid 19th century.” Frontiers in Psychology published: xx April 2015 doi: 10.3389/fpsyg.2015.00361

https://drive.google.com/file/d/0B3c4TxciNeJZN1g0NjF0WmtUeHc/view?usp=sharing

It has been theorized that declines in general intelligence (g) due to genetic selection
stemming from the inverse association between completed fertility and IQ and the Flynn effect co-occur, with the effects of the latter being concentrated on less heritable non-g sources of intelligence variance. Evidence for this comes from the observation that 19th century populations were more intellectually productive, and also exhibited faster simple reaction times than modern ones, suggesting greater information-processing ability and therefore higher g. This co-occurrence model is tested via examination of historical changes in the utilization frequencies of words from the highly g-loaded WORDSUM test across 5.9 million texts spanning the period 1850–2005. Consistent with predictions, words with higher difficulties (δ parameters from Item Response Theory) and stronger negative correlations between pass rates and completed fertility declined in use over time whereas less difficult and less strongly selected words, increased in use over time, consistent with a Flynn effect stemming in part from the vocabulary enriching effects of increases in population literacy. These findings persisted when explicitly controlled for word age, changing literacy rates and temporal autocorrelation. These trends constitute compelling evidence for the co-occurrence model.

The co-occurence model is the decidedly unsexy name given to the theory that Flynn effects and dysgenic effects co-occur. I call it “the leaky boats hypothesis” (Loehlin, 1997) : Flynn effect is the rising tide; Woodley effect the leaky boats.

In the West, up until the early to mid 19th century, those with high levels of socioeconomic status, wealth, and education (all of which are proxies for intelligence; Herrnstein and Murray, 1994) had higher numbers of surviving offspring relative to those with comparatively lower levels (Clark, 2007; Skirbekk, 2008), suggesting that higher intelligence may have conferred fitness advantages
on individuals having to cope with extremes of cold, disease outbreaks, and conflict (Woodley and Figueredo, 2013). Subsequent increases in global temperature, coinciding with the end of the Little Ice Age in the mid-19th century, reduced environmental harshness, boosting agricultural yields thus reducing ecological
stress and conflict (see: Zhang et al., 2007, 2011 for a demonstration of the inverse historical relationship between temperature and conflict). This would have substantially relaxed selection against those with lower intelligence (Woodley and Figueredo, 2013). This was coupled with advances in medicine (which would have included better means of fertility control, hygiene, nutrition, and medication; Lynn, 2011), and also social innovations such as welfare, mass schooling, and universal healthcare. The combined effect of these was a demographic transition characterized
by general reductions in fertility, which were most pronounced among those with higher intelligence (Lynn, 2011). This was mediated primarily by fertility control coupled with the increasing prevalence of opportunities to delay fertility (i.e., higher
education, increasing status competition, etc., which disproportionately attenuated the fertility of high-IQ.

 

As the authors say: More difficult words presented sharper historical declines in usage
over the 1850–2005 period, []words for which pass rates are more negatively
associated with fertility are decreasing in usage over time, which is consistent with those being the more difficult words []words that are both more difficult and for which pass rates are more negatively associated with fertility are decreasing over time.

It may be a minor matter, but I did my own little analysis, and find that word A is an outlier. It is very easy, and much more frequent than the other items: all the other words are rare by comparison. Every test needs to start with an easy item, but I wonder how much work this particular word does. However, even this very common word shows exactly the same trend as the other easy, but far less frequent words.

In sum, have Woodley et al. put another crucial piece into the dysgenic jigsaw? At the moment, it looks like it.

I sent the messenger boy off with his usual shilling, and noticed a certain impudence as he accepted it. Perhaps the under kitchen maid has been spreading false rumours about me, in her contumely way.

Bigger brains are not necessarily more efficient.

An anonymous commentator on the post “Bigger brains cause Flynn effect” said as follows:

So we are supposed to believe that digit span is plummeting, color perception is getting worse, writing is being dumbed down for everyone, our reaction times will soon be so bad we will be unable to play Doom - and also that brain sizes are increasing and this explains the Flynn effect and the effect is genuine rather than hollow?

Michael Woodley of Menie replies:

Simple answer:

Bigger brains are not necessarily more efficient.

Complex answer:

There is a considerable amount of evidence indicating that brain size and general intelligence (g) are actually quite independent from one another. In humans it has been found that the evolutionary lability of brain volume is low, relative to what would be expected of g (Miller & Penke, 2007). This suggests that different selection pressures operate on each trait. The best evidence for this comes from the observation that there has been a general tendency towards decreasing brain volume in human populations over the last 30,000 years (Beals et al., 1984), despite molecular indications of increases in g over the same time period (Rindermann et al., 2012). This finding generalizes in cross-species comparisons involving primates – brain size appears to be relatively phylogenetically conserved across taxa, whereas g (or G as we are talking about species differences) shows signs of having been subject to accelerating directional selection (Fernandes & Woodley of Menie, 2014).

Selection for g therefore seems to be associated with increases in the efficiency of neural substrates, which does not require an increase in overall brain mass, and can even occur in tandem with reductions in brain mass. Several causes of this have been proposed, to my mind however the most plausible explanation is that it is a simple matter of thermodynamics – the boosting of g via a relatively low investment into streamlining the brain’s neural architecture rather than via a high investment increasing of its bulk is the path of least resistance in terms of energetics.

It is important to note also that brain structure does not exhibit the property of measurement invariance across individual humans – large brains are not simply scaled up versions of smaller ones (e.g. Semendeferi et al., 2011). This finding is consistent with the observation that g-loading is only a weak to modest moderator of the strength of the association between brain volume and measures of cognitive ability (Woodley of Menie et al., in preparation), as it indicates that volume-related changes in the structural organization of the brain have substantial effects on specialized cognitive abilities, not just g. It also helps explain the recent ‘downgrading’ of the magnitude of the brain volume-IQ correlation to .24 (Pietschnig et al., 2015), as much of the mass of the brain is associated with functions that are completely unrelated to cognition, but can nonetheless vary considerably from individual to individual.

The relative independence of brain size from g can therefore plausibly account for the co-occurrent secular trends towards decreasing neurological efficiency (suggesting decreasing g) on the one hand coupled with indications of increasing brain mass. I do not anticipate that the larger brains of modern populations are structured in the same way as the relatively smaller brains of a century ago. I predict that most of the mass increase will have been driven by disproportionate investments of grey matter into features of the brain responsible for memory and learning, such as the right hippocampal formation, the right dorsolateral prefrontal cortex, the cerebellum and the septum pellucidum. The net of this will be modern brains that, whilst less generally efficient, are nonetheless better able to develop the sorts of g-independent specialized abilities latent in the Flynn effect

References

Beals, K.L., Smith, C.L., & Dodd, S.M. (1984). Brain size, cranial morphology, climate, and time machines. Current Anthropology, 25, 301–330.

Fernandes, H. B. F., & Woodley of Menie, M. A. (2014, June). Differences in

evolutionary patterns and rates of general cognitive ability compared to

neuroanatomical indicators in the primate phylogeny. Oral presentation, Evolution

2014, Raleigh, NC.

Miller, G.F., & Penke, L. (2007). The evolution of human intelligence and the

coefficient of additive genetic variance in human brain size. Intelligence, 35, 97–114.

Pietschnig, J., Penke, L., Wicherts, J.M., Zeller, M., & Voracek, M. (2015). Meta-analysis of associations between human brain volume and intelligence differences: How strong are they and what do they mean? Neuroscience and Biobehavioral Reviews, 57, 411–432.

Rindermann, H., Woodley, M.A., & Stratford, J. (2012). Haplogroups as evolutionary markers of cognitive ability. Intelligence, 40, 362–375.

Semendeferi, K., Teffer, K., Buxhoeveden, D.P., et al. (2011). Spatial organization of

neurons in the frontal pole sets humans apart from great apes. Cerebral Cortex, 21,

1485-1497.

Woodley of Menie, M.A., Fernandes, H.B.F., te Nijenhuis, J., & Metzen, D. (In preparation). Modest support for the processing volume theory of general intelligence: A meta-analysis of the Jensen effect on brain volume (under review).

Woodley launches his Victorian defence

 

You may recall that I promised  in November last year that young Woodley would counter-attack his tormentors, who have now been caught startled, without their gum shields. Vicious uppercuts are battering the proffered chins of his adversaries, the redoubtable Mighty Champion Jim Flynn, a grizzled New Zealand pugilist, mentored by the great Jensen himself; the Australian Ted Nettlebeck, sun-bleached and hardened by the toil of 20 years of inspection time; the experienced Silverman, a quieter fighter, with a good solid punch, the original collector of historical reaction times; and the formidable Russian Dodonov and Dodonova duo, an unusual husband and wife combination of legendary aggression.

After a long wait, in a burst of pent up energy and a flurry of punches, Woodley, te Nijenhuis and Murphy break free, and in a phrase made current by D Day commemorations “all hell breaks loose”. 

The Woodley gang argue that, once they have done a complete re-analysis to respond to the points raised against their original “Victorians” paper, their new results reveal a seemingly robust secular trend towards slowing reaction time in these two countries, which translates into a potential dysgenics rate of −1.21 IQ points per decade, or −13.9 points in total between 1889 and 2004. We conclude by arguing that the best way forward is to test novel predictions stemming from our finding relating to molecular genetics, neurophysiology and alternative cognitive indicators, thus shifting the research focus away from the purely methodological level towards the broader nomological level. We thank our critics for helping us to arrive at a much more precise estimate of the decline in general intelligence.

Michael A. Woodley, Jan te Nijenhuis, Raegan Murphy. Is there a dysgenic secular trend towards slowing simple reaction time? Responding to a quartet of critical commentaries. Intelligence

I highlight Table 1 which shows how the Wechsler subtests relate to simple reaction times and inspection times. What interests me is that the most substantial of the rather low correlations is with Information at 0.3, which does not immediately make sense, unless of course you see reaction time as a measure of crystallized verbal intelligence, which the other correlations with Arithmetic and Vocabulary would tend to confirm. Inspection Time, on the other hand, relates most strongly to Object Assembly 0.393 and Coding 0.351 and Block Design 0.306 which are all Performance subtests. Of course, this table is particularly interesting because of the g loading and heritability data.

 

 

https://drive.google.com/file/d/0B3c4TxciNeJZN29lSlpmdmlOcVE/edit?usp=sharing

 

I am heartily glad to see this paper published, because I have been sitting on it for many months, awaiting the final permission from the authors, who in turn were waiting for the conclusion of the peer review process, which is intended to achieve a quality standard, which it often achieves. It is not intended to delay the timely publication of academic work, a malign outcome it certainly achieves. A great pity.

Flynn effect as a retesting, rule-based gain

It is very good to see a paper which takes a large scale effect, the secular rise in intelligence test results, and links it to an intriguing large scale explanation. A new contribution to understanding the Flynn Effect is to be found in the journal Learning and Individual Differences, which became available 30th October.  Elijah Armstrong and Michael Woodley “The rule-dependence model explains the commonalities between the Flynn effect and IQ gains via retesting” http://www.sciencedirect.com.libproxy.ucl.ac.uk/science/article/pii/S1041608013001556

Woodley you already know, but more about Armstrong later. Armstrong and Woodley argue that the Flynn effect is partly driven by the retest effect, whereby familiarity with the test material means that if you can learn a rule of thumb you can solve those particular sorts of problems when you see them again, without having to use much intelligence. In very simple terms, the test wears out quickly once you get to learn how it works. Using implicit learning and working memory, test takers learn how to solve rule dependent problems, which leads to apparent IQ gains which are partly independent of general intelligence.

As readers of this blog will know, the ultimate IQ test is the one for which no-one knows the answers at the moment. Intelligence tests in the real world are more modest affairs. Raven’s Matrices is a test based on progressions: you need to find the rule which underlies the visible changes in the problem arrays, and a good enough memory to hold in mind how those changes are progressing, so that you can correctly choose the final missing picture. For example, if the figures are growing as they move from left to right, and getting paler as they move from top to bottom, you still have to remember exactly how large and pale the missing item should be when you check through the proffered options. Carpenter et al. (1990) found that 5 rules covered all the items in the test. Once you know that, it is less of a test.

Another aspect of being test savvy is the capacity to de-contextualise, that is, to be able to generalise about types of problem, without being confused by the particular context in which the specific example is presented to you.

Armstrong and Woodley assert that, from the point of view of intelligence, education amounts to a vast re-testing enterprise. There are modest gains from rules of thumb, mnemonics and being “taught to the test”. Indeed, the reliance on exam results makes teachers and pupils confederates in ensuring that nothing is taught which is not taught to be examined. Incidentally, this view does not exclude what James Flynn calls “scientific spectacles” which more people now adopt when solving problems.

Armstrong and Woodley rank tests according to how much “cognitive scaffolding” they have. Raven’s Matrices is level IV: rules are very helpful, only a few of them are required; Catell Culture Fair is Level III: rules help, but will not help you on many items; the majority of IQ tests are Level II: very many rules are required, but working out which to use is difficult, (and selecting the rule is what requires general intelligence); and Draw A Man test is Level I: no rule is of much help.

They then simply correlate the vector of the position of any particular test in the rule dependence typology with the vector of the size of the Flynn effect on that test. A positive correlation would indicate that tests that were more dependent upon rules were yielding the larger Flynn effects. They tested it on 14 data sets, and found a correlation of 0.6

 

 

The authors say: “It is proposed that tests like the Raven’s are only highly g loaded when encountered initially — even basic familiarity with the rules and heuristics on a test, or familiarity with inductive reasoning itself, has the potential to radically diminish the g loading of this test over time, both under controlled conditions (such as in a retesting scenario) and over larger societal time scales (i.e., across generations in the case of the Flynn effect).”

They continue: “The increasing capacity of societies to detect and explicitly utilize rules as a function of the Flynn effect may be related to increasing rule exposure via mass education and to ‘ways of thinking’ endemic to cognitive modernity (Flynn, 2009). It may also be caused by increased rule sensitivity as a consequence of changes in brain functioning that might relate to the prevalence of slower life history strategies in the modern era. These in turn might be in part a change in life history strategy due to dramatic improvements in environmental quality.”

This is a good paper. It contains lots of ideas, proposes a theory and then tests it, and draws out the conclusions in a thoughtful way. Not content with linking the observed phenomenon with the Flynn Effect and life speed theory, it also includes 5 testable predictions, to encourage other researchers to test whether their proposal has merit. It is a notable debut for the first author, whose first paper this is, and whose ideas formed the basis for the eventual publication.

Postscript

Elijah lives in Marin County, California, and is interested in philosophy and intelligence research. He originated the rule-dependence model in early 2012 and worked on it for eighteen months thereafter. He claims his conscientiousness is below the 10th percentile. He is also prone to end all his emails saying “Excuse typos, I typed this with my feet”. If you imagine that he is a sad old man gathering up a lifetime of scholarship into a well-honed rant, your imagination would be wrong. Elijah is 15. Welcome to a lifetime of academic labour!

The puzzle of falling French intelligence

In June I reported on the work of Edward Dutton and Richard Lynn in “A negative Flynn Effect in France, 1999 to 2008–9” Intelligence 51 (2015) 67–70.

http://drjamesthompson.blogspot.co.uk/2015/06/is-france-sinking-even-further.html

I wrote that they had looked at a small but probably representative sample used by the Wechsler team in their 2011 French standardisation of the adult form of their general intelligence test. They say: The results of the French WAIS III (1999) and the French WAIS IV (2008–9) are compared based on a sample of 79 subjects aged between 30 years and 63 years who took both tests in 2008–2009. It is shown that between 1999 and 2008–9 the French Full Scale IQ declined by 3.8 points.

If true, this is a substantial drop in ability. The authors did not furnish an explanation, though they considered a few possibilities. In my comments I suggested a couple of reasons (apart from small sample size) that the results might not be as solid as imagined, but still felt that there had very probably been a drop in ability.

Now the paper has been looked at by Michael Woodley and Curtis Dunkel who examine causal explanations in more detail.

Michael A. Woodley of Menie and  Curtis S. Dunkel. In France, are secular IQ losses biologically caused? A comment on Dutton and Lynn (2015) Intelligence, Volume 53, November–December 2015, Pages 81–85 doi:10.1016/j.intell.2015.08.009

https://drive.google.com/file/d/0B3c4TxciNeJZS1hPOHMyUGpOVVk/view?usp=sharing

The authors say: Dutton and Lynn report secular declines in Fullscale IQ evaluated using WAIS of four points a decade in France between the years 1999 and 2008–9. It is posited that the trend may have a partially biological cause, stemming from dysgenic fertility and, to a lesser extent, replacement migration. Given that these, and other biological phenomena are associated with the Jensen effect, it is expected that if they are the principal causes of the IQ decline then the secular change should also be associated with the Jensen effect. Furthermore if it can be demonstrated that the vectors of secular IQ decline, g loadings and the vectors of other biological indicators share variance, then the case for biological causation will be strengthened. Using the method of correlated vectors and error disattenuation, the secular IQ declines are shown to be associated with a high-magnitude Jensen effect (ρ = .833). A multi-vector common factor comprised of the vector of g loadings along with the vectors of three biological variables (subtest heritabilities, dysgenic fertilities and simple visual reaction times) was found to load substantially on the secular IQ decline vector (λ = .723). These findings indicate that the French secular IQ loss likely has a primarily biological cause.

How do the authors come to this conclusion?

It has been observed, with a few of exceptions, that variables which associate with IQ subtests to a greater extent, when the measure is more g loaded, tend to be biological (i.e. pertaining to genetic and physiological factors) and include factors such as population, race and species-level differences in cognitive ability ( Fernandes et al., 2014, Rushton, 1999 and Rushton and Jensen, 2010), subtest heritabilities ( Woodley of Menie, Fernandes, & Hopkins, 2015) and inbreeding depression effects ( Rushton, 1999 and Rushton and Jensen, 2010). Collectively these have been termed ‘Jensen effects’ ( Rushton, 1998).

Factors that exhibit the opposite tendency, i.e. associate with less g loaded abilities to a greater extent (and are in consequence ‘anti-Jensen effects’), are typically environmental or cultural in origin, such as IQ gains accrued via retesting ( te Nijenhuis, van Vianen, & van der Flier, 2007), gains accruing from the adoption of low IQ children into high IQ homes ( te Nijenhuis, Jongeneel-Grimen, & Armstrong, 2015), those accruing from intensive educational interventions ( te Nijenhuis, Jongeneel-Grimen, & Kirkegaard, 2014) and the Flynn effect ( te Nijenhuis & van der Flier, 2013).

First, they correlate the vector of French secular IQ decline magnitudes with the vector of subtest g loadings from the French standardization of the WAIS-III. This is the method of correlated vectors. They also correct for measurement errors.

Second, they construct a multi-vector common factor using the vector of the secular IQ declines and subtest g loadings along with the vectors of various biological indicators, including subtest heritabilities, Subtest-fertility (dysgenic) correlations and simple visual reaction time-subtest correlations.

The raw vector correlation is 0.38 and the corrected estimate 0.833. The corrections are reasonable, but the authors are clear that there is no way to get round the smallness of the sample, so I see this as just an indication of the underlying trend.

This adds in the dysgenics estimates and simple reaction time results, and the reliabilities, to give a much fuller and more intriguing picture.

Finally, they show the correlations of the vectors and bring the whole thing together:

Crucially, the loadings for g, heritability and secular IQ declines are all positive.

The authors say: The French secular IQ declines are associated with modest and large-magnitude (based on Cohen, 1988; small = .1 to .29, modest = .3 to .49, large = .5 to 1)¹ Jensen effects when both the French WAIS-III normalization g loadings and the meta-analytic manual g loadings from Kan (2011) are used (r = .38 and .658 respectively; the two sets of g loadings exhibit a large-magnitude correlation: r = .626, N = 9 subtests). When corrected for four sources of error, the vector correlation between the French WAIS-III g loadings and secular IQ declines increases to .833 indicating a high-magnitude Jensen effect.

They concede that there is high measurement error, and they and the original authors agree on this point.

The results of the multi-vector analysis are consistent with Rushton's (1999) prediction that the vectors of biological variables and also g loadings should cluster with one another, forming a biological nexus. All loadings of the multi-vector common factor on its components are of large magnitude (λ = .505 to .854). The loading of the vector of secular IQ decline (λ = .723) indicates an association between this variable and other biological variables, which supports the speculation advanced in Dutton and Lynn (2015)concerning possible biological causes of the French IQ decline.

Replacement migration in France involving populations exhibiting lower means of IQ and higher rates of total fertility, such as Algerians, Moroccans, Tunisians and Roma (Čvorić, 2014 and Lynn and Vanhanen, 2012) may be increasing the rate of secular losses at the level of g, consistent with speculations advanced in Dutton and Lynn (2015), however the additional loss in g due to this process is anticipated to be very small. Based on a simulation, Nyborg (2012) estimates that in Denmark, replacement migration may be reducing heritable g by .28 points per decade, which would increase the overall loss in gto 1.51 points per decade ( Woodley of Menie, 2015), this still being only 37.75% of the loss observed in the French cohort.

Another possible contributing factor is the so-called “brain drain” (De Rugy, 2012), which involves high-g French individuals emigrating to countries that offer more competitive salaries and better working conditions. Thus human capital flight between 1999 and 2008–9, especially among the younger demographic, may have contributed to the French secular IQ decline, however the precise impact of the effect is difficult to determine.

Brain drain is certainly a possibility: the “South Kensington effect” of French emigres clustering round the Lycée français Charles de Gaulle is a result of London hosting roughly 270,000 French. The number is less significant than the fact of them being highly qualified and entrepreneurial, a real smart fraction.

Now the authors’ approach should be used to look at the more recent paper by Jakob Pietschnig and Georg Gittler on an equivalent fall in intelligence in Austria and Germany. Will they find the same result?

http://drjamesthompson.blogspot.co.uk/2015/11/deutschland-uber-alles-dann-unter-allen.html

It is a minor point, but authors reporting falls in intelligence sometimes describe it as “a negative Flynn Effect”. Whilst technically true, this somewhat underplays what is going on. If you strip out from the apparently rising scores that portion which is due to measurement error (changes in material, in scoring, in standardisation and possibly in student guessing) then the rest is assumed to be due to better environments: education, health and prosperity. The original assumption was that once everyone was on a level playing field of externally provided good circumstances, then intellects would reach a plateau of high functioning, but a plateau nonetheless. Jim Flynn said he was always surprised at how long the effect was continuing. He felt that once the deficits in living circumstances had been corrected, it would stop. However, as far as I know, no-one apart from those looking at dysgenics had predicted that intelligence would fall. I think we should refer to falling intelligence as Falling Intelligence. Either that, or follow Charles Murray in calling it the Woodley Effect

The work by Woodley and Dunkel serves as a general method of estimating the biological component in intellectual decline, a key explanatory component of the Woodley Effect. It should be tested widely.

 

Flynn effect raises all boats, but some are leaky

Woodley, te Ninjehuis and Murphy (2013) have put together an interesting paper. In looking for the Flynn effect they have eschewed intelligence test data, and instead gone for simple, old-fashioned (1884) simple reaction times. This is about the most basic thing you can measure in the nervous system: a signal is presented and the organism responds. It is a crude measure of whether the organism can sense and respond to its environment, and how long it takes to do so.

Much has been made of more complex measures. For example, the complexity of the signal has an impact on response times. It is easier to respond to one light on its own than to watch out for one of two lights, even if they are relatively close to each other, because having to monitor two potential sources of signals imposes a slight load on the nervous system. If you make the task even more complex by requiring responses to patterns of five lights, then reaction times slow even further, following Hick’s Law (that the slope of reaction times will follow a binary choice log₂ function of the number of choices).  

Other sophisticated variations are to distinguish between movement time (taken up by moving your arm) and decision time (time spent looking at the shining light and working out that it is now time to respond).

Simple reaction times are back in fashion. Among other things, they are good at predicting lifespans. See “Can I have a reaction” in order to test your own reaction times, and guess at your lifespan, though we need to go to another data set from Ian Deary for that.

By way of background, both intelligence and reaction speed are heritable at 0.58 and have a correlation with each other of about 0.31. If one corrects for restriction in age range and for lack of reliability the measure probably account for half of the variance in intelligence.  This paper suggests that something seems to be slowing us up. If the Flynn effect is absolutely real, then that should not be the case. We should be super-fast at simple reaction times.

Woodley, te Nijenhuis and Murphy  have conducted a meta-analysis of 14 studies involving Western subjects from 1884 to 2004, which provides them with 16 data points with which to draw the linear regression function showing increased reaction times over 120 years. Interpreting the cause is a different matter. It is possible, but unlikely, that we have been poisoned by some neuro-toxin which is making us sluggish: lead, perhaps. However, lifespans are going up in most of the world, and certainly steadily up in the rich West. Also, lead does not have its main effects on measures of general intelligence. Another possibility is that many people who in earlier eras would have died have now survived their illnesses because of modern medicine, but survive with sluggish reactions. The last option considered by the authors is increasing mutation load, perhaps reducing myelination of neurones, with a consequent reduction in the efficiency of signal transmission and information processing in the brain.

It is possible that at least two contradictory factors are at play here: a welcome general increase in living standards, with much better access to food, housing, health and education boosting intelligence on the one hand; and on the other hand a smaller but persistent increase in mutational load with deleterious intellectual effects, thus cancelling some of the gains. (The rising tide of the Flynn effect raises all boats, but many of those boats are leaky).  If the latter is true, then it ought to be possible to find further evidence to support the hypothesis.  Disentangling the Flynn effect from the Woodley effect will be difficult, but also very illuminating, because we will learn much about the future of human intelligence.

Please cite this article as: Woodley,M.A., et al.,Were the Victorians cleverer than us? The decline in general intelligence estimated from a meta-analysis of the slowing of simple reaction time, Intelligence (2013), http://dx.doi.org/10.1016/j.intell.2013.04.006

                                                                                                                                 

ISIR closes on dysgenic note

 

Just as delegates are congratulating themselves on having attended a feast of intelligence research in Melbourne, they are given a reality check by young Woodley, who has been looking at climate data from the cheerful perspective of calculating how much of the peasantry were killed off in cold winters, thus allowing the brighter folk to prosper.

Climatic Variability, Group Selection and Dysgenics: Testing a Multi-Level Selection Model
Michael AWoodley1, Heitor B. F. Fernandes2, Aurelio José Figueredo3
1Umeå University, Sweden & Vrije Universiteit Brussel, Belgium
2Federal University of Rio Grande do Sul, Brazil
3University of Arizona
Michael.Woodley@psy.umu.se; heitor.barcellos@ufrgs.br; ajf@u.arizona.edu

Novelty. A multi-level selection model published recently by Woodley and Figueredo
proposes that climatic changes have historically affected the direction of gene-frequency changes for g via their alternating impact on group vs. individual level fitness. In the West, colder environments imposed high extrinsic mortality on peasantry, whilst also creating fitness opportunities for those with higher-g. This also encouraged group selection for ultra high-g but low-fitness geniuses, whose innovations facilitated range expansion (i.e. colonialism).
Warmer environments led to lower mortality amongst those with low-g. Concomitant social and scientific innovations (i.e. welfare, medicine) further increased the mildness of Western environments, leading to diminished group selection, coupled with greater individual level selection for those with low-g responding to the fitness-incentives provided by the improved ecology, in addition to individual level selection against those with high-g, whose fitness diminished in the face of improved fertility control and redistributionist economic policy.
Importance. Multiple indexes of major innovation in science and technology indicate a pronounced per capita decline commencing in the latter half of the 19th century. Indexes of per capita scientific genius show a similar decline. Woodley and Figueredo, using hierarchical structural equations modelling, found that both of these trends relate to simulated declines in heritable g estimated on the basis of the negative relationship between fertility and IQ throughout this period. Recently, much attention was paid to the finding that simple reaction time performance seems to have been slowing throughout this same period, suggesting that the dysgenic decline in g predicted in previous works might be an actuality.
These findings are all consistent with the multi-level selection model as described above. Understanding how these ecological factors might explicitly relate to real changes in the patterns of selective pressure is important for understanding the interconnected and varied nature of the determinants of accelerating adaptive biological and cultural evolution amongst Holocene populations.
Methods. Here we test the multi-level selection model over the last 1.5 centuries using a cascade General Linear Model. Climate warming is operationalized using three convergent indicators of global temperature anomaly means spanning the period from 1859 to 1975. A lexical approach to measuring historical attitudes was used to determine group selection strength in the US+UK. Three convergent group selection \'loaded\' words were selected, and their diminishing frequencies across printed matter were measured using Google Ngram. Declining g was measured using meta-analytically matched simple reaction time trend data from the UK+US corrected for various sources of error, spanning the period 1889 to 1993. US+UK innovations were taken from a database of global innovations and weighted on the basis of US+UK population growth.
The model: Climate warming -> Group selected attitudes (with a lag of ten years) ->
Declining g (with a lag of one generation) -> Innovation rates; fit excellently. The fit
improved when war years were excluded from the innovation index. This is consistent with the model.

Contact the authors above for drafts of their presentation.

Can young Woodley make a comeback?

 

You will recall that his opponents had left young Woodley (him of the Edwardian frock coat and the gold pince nez glasses) in a dazed condition after four rounds of gruelling counter argument.

http://drjamesthompson.blogspot.co.uk/2013/11/is-young-woodley-down-for-count.html

I now hear from his training camp that the young challenger is about to enter the ring again, claiming he will be able to give “a big response”. Is this the bravado of youth, or has he found the new punches with which to vanquish his fearsome opponents? I will be wagering a whole five guineas on Woodley. By the way, the young challenger has a new slogan he is likely to chant at the weighing in ceremony: “The Victorians were still  cleverer than us”.

More news exclusively from this blog, as soon as the reply paper gets the final finishing touches.

Goodbye Sweden: Can I have a quick reaction?

 

Journalists, being fed news of some dreadful event, are prone to ask their studio guests: “Can I have a quick reaction?” Almost always the Talking Head comes up with an off-the-cuff reaction, also known as an opinion, as to whether the event is the end of: a dictator/a government/a country/low cost oil/Western civilization/the planet.

I would not dream of criticising this response, particularly because in former times on TV I sometimes ventured minor versions of such a response. I have not yet been asked to comment in a public arena as to whether the finding that contemporary reaction times are slower than in times of yore indicates the decline and fall of our civilization. You know the story full well: the much championed Flynn effect suggests that good food, free education and proper drains have boosted our intelligence, as well they might have; the Woodley effect suggests we are slowing up, losing our intellectual sparkle, becoming more specialised in our abilities but very probably sinking into the mire of soggy stupidity.

Now we have some even more solid findings to favour The Woodley Effect. (By the way, Charles Murray, responsible for coining The Flynn Effect,  suggested to me that the contemporary lowering of intellect should be named in this way).

Guy Madison, Michael A. Woodley of Menie and Justus Sänger

Secular Slowing of Auditory Simple Reaction Time in Sweden (1959–1985) Front. Hum. Neurosci., 18 August 2016 | http://dx.doi.org/10.3389/fnhum.2016.00407

They say: There are indications that simple reaction time might have slowed in Western populations, based on both cohort- and multi-study comparisons. A possible limitation of the latter method in particular is measurement error stemming from methods variance, which results from the fact that instruments and experimental conditions change over time and between studies. We therefore set out to measure the simple auditory reaction time (SRT) of 7,081 individuals (2,997 males and 4,084 females) born in Sweden 1959–1985 (subjects were aged between 27 and 54 years at time of measurement). Depending on age cut-offs and adjustment for aging related slowing of SRT, the data indicate that SRT has increased by between 3 and 16 ms in the 27 birth years covered in the present sample. This slowing is unlikely to be explained by attrition, which was evaluated by comparing the general intelligence × birth-year interactions and standard deviations for both male participants and dropouts, utilizing military conscript cognitive ability data. The present result is consistent with previous studies employing alternative methods, and may indicate the operation of several synergistic factors, such as recent micro-evolutionary trends favoring lower g in Sweden and the effects of industrially produced neurotoxic substances on peripheral nerve conduction velocity.

The authors have collected new data on a large sample, with 7081 usable respondents on which there was much background material from previous testing. They pursued the respondents with reminders, and tested them online, using the best available software to ensure consistent exposure and recording of responses. This cannot be the same as bringing them in to a standard experimental set up of reaction time equipment, but on the other hand it generates much higher numbers of respondents. They have also considered the impact of these variations in methods which, if anything, would obscure rather than reveal underlying trends.

Reaction times seem to slow up after 1970. The authors say:

We found clear trends toward slowing auditory SRT when birth year was regressed against year-on-year SRT means for the years 1959–1985. It is notable that even without adjustment for aging, the SRT speed of the oldest participants is about the same as that of the subsequent generation, whom in the late twenties are supposed to have the shortest SRTs of all age groups (Der and Deary, 2006).

the secular slowing trend was present in all cohort comparisons (males, females, and both sexes combined), and was significant across the entire range of birth years for both the males and the whole sample, but not for the females, who nonetheless exhibited an overall negative trend in SRT performance consistent with potential secular slowing.

A potential cause of the apparent slowing may be exposure to neurotoxic industrial by-products such as heavy metals (Silverman, 2010) and dioxins (ten Tusscher et al., 2014), which may reduce SRT performance via their effects on peripheral nerve conduction velocity. However, as Silverman notes, known neurotoxins have come under tight governmental regulation, emissions have tended to decrease, and serum levels of lead, for example, have decreased since 1970 in the USA (Silverman, 2010, p. 46).

Another possible cause of this trend may be relatively recent micro-evolutionary trends favoring lower g in the population of Sweden. Several studies have revealed that g and fertility are inversely related in the US and the UK (as reviewed in Woodley of Menie, 2015) among cohorts born as far back as the 1890s (Lynn and Van Court, 2004; Lynn, 2011). However, the relationship between g and fertility in Scandinavian countries is less well characterized. Only one study has attempted to examine these trends across birth cohorts in Sweden (Vining et al., 1988). Utilizing aggregate data on fertility and IQ for a mixed-sex sample of Swedish cohorts resident in Stockholm county and born between 1909 and 1940 from Vining et al. (1988), it was possible to reconstruct predicted generational changes in genotypic IQ (I.e., the heritable variance component of IQ) due to the changing patterns of selection (I.e., the correlation between IQ and fertility established for each cohort) for four cohorts (see Appendix 2 for details of the method).

Main result here, but see the full paper:

In sum, this is strongly suggestive of a slowing of reaction times in Sweden, itself suggesting a possible drop in mental alertness and intelligence in that country. If the Flynn effect were a deep-seated real improvement in functioning then one would expect faster reaction times, not slower. An alarming result, worthy of further testing and attention.