Luminant Victorians: The Battle of the Bulbs

 

You will remember young Woodley, who used the fact that reaction times have slowed up since Victorian times to argue that the quality of the species is going downhill, and that British seed is deteriorating, a fact currently obscured by the liberal application of fertiliser, but dysgenics will be the end of us in the end.

Up pops Scott Parker with a counter argument, though couched with scholarly diffidence and understatement “Were the Victorian clever than us? Maybe, maybe not”. I do not know Scott, but he seems to need the assertiveness training which I thought was guaranteed to all US citizens by the Constitution, so that he can come out as a firm “Maybe not” enthusiast.

https://drive.google.com/file/d/0B3c4TxciNeJZS1BqZHpHMGNHVU0/view?usp=sharing

What Parker avers is that the snappiest reaction times were probably due to the extremely bright and noisy lamps used by Victorians, as opposed to duller and quieter bulbs in more recent times. His  paper launches a luminescence skirmish, the Battle of the Bulbs.

the observations that are crucial to the Woodley et al. (2013) finding are the earliest ones—those from Galton (as reported in Johnson et al., 1985) and Thompson (1903).
Both of those data sets report very short reaction times and contribute greatly to the correlation between RT and year of report. Do those short reaction times betoken a high level of intelligence among the Victorians? In one of those cases, another factor may have contributed. Thompson (1903) generated her stimuli, flashes of purple light, using a Geissler tube—an ancestor of the fluorescent tube (Hick, 1952). But Dunlap and Wells (1910) chose to use a different light stimulus generator, explaining (p.320) that, “A Geissler tube could not be used, on account of the noise accompanying its flash.” Auditory RTs, like visual RTs, grow faster with increasing stimulus intensity (Luce, 1986). We would need to know both the auditory and visual intensities of the Geissler tube to know if Dunlap and Wells's concern was well-founded. But we cannot rule out the possibility that Thompson's subjects were reacting to a noise functionally more intense than the flash she intended as the stimulus, thereby resulting in shorter RTs than her light stimulus alone might have produced. The magnitude of any such shift cannot be estimated.

Parker then somewhat goes against this speculation, by showing two more recent studies where the reaction times are not faster with the brighter lamp. Undaunted, he says this might be due to the greater size of the stimulus showing the faster reaction time.

we can see some indication of the power of other factors by looking again at some details of the data reported by Minucci and Connors (1964) and Cardello (1979). One of Minucci and Connors's stimuli was about double the luminance of one of Cardello's. Nonetheless, comparing the results across the studies at those two stimulus intensity levels, Minucci and Connors's subjects' mean RT was 235 ms whereas Cardello's subjects' mean RT was only 207 ms. Minucci and Connors's
stimuli subtended a visual angle of 1° whereas Cardello's stimuli subtended a visual angle of 6°; Teichner and Krebs (1972) indicate that larger stimuli produce shorter RTs, so perhaps that contributed to the faster RTs reported by Cardello. Of the studies inventoried in Woodley et al. (2013) only Reed, Vernon, and Johnson (2004) specify the size of their stimuli. All their stimuli were smaller than 1°, and their mean reported RT was not notably long.

He echoes the Dodonova and Dodonov conclusion that: many details of experimental procedure influence the size of visual RT, and that makes it very difficult to draw firm conclusions about the source of differences in RT found by studies that differ in procedural details as well as year of data collection.

His conclusion: The Victorians may well have been cleverer than us, but the visual
RT data do not suffice to prove the point.

I have had enough of this. Why haven’t these reaction time people ever standardised their research instruments? When I went to psychological conferences I imagined these experimentalists were real scientists who used proper techniques, unlike us arty clinical psychologists, who measured humanity in the round, with paper and pencil tests, and a bleary clinical eye. I trusted experimentalists their black boxes (both conceptual and electronic) their flashing lights, and their results precise to three decimal places. If their actual results were so sensitive to lamps, timers, response keys and software as to be incapable of comparison from one decade to the next, and one experimentalist to the next, then late in the day I find that my idols have clay feet. They are in almost as much of a mess as psychometricians, who can show good predictability of results one cohort at a time, but have more difficulty calibrating the achievements of one generation against the next.

Lytton Stachey’s  (1918) “Eminent Victorians” was championed in my school days as the apotheosis of wry commentary over hagiography, a sharp and irreverent hatchet job on the brightly illuminated heroes and heroines of Victorian times. He is judged to have destroyed for ever the Victorian age’s pretensions to moral superiority. Of course, since Victoria had died in 1901, Strachey is only partly Victorian, having lived only the first 21 but most impressionable years under her reign. I think you can judge from which era his prose style derived by looking at the first paragraph of his Preface:

THE history of the Victorian Age will never be written; we know too much about it. For ignorance is the first requisite of the historian—ignorance, which simplifies and clarifies, which selects and omits, with a placid perfection unattainable by the highest art. Concerning the Age which has just passed, our fathers and our grandfathers have poured forth and accumulated so vast a quantity of information that the industry of a Ranke would be submerged by it, and the perspicacity of a Gibbon would quail before it. It is not by the direct method of a scrupulous narration that the explorer of the past can hope to depict that singular epoch. If he is wise, he will adopt a subtler strategy. He will attack his subject in unexpected places; he will fall upon the flank, or the rear; he will shoot a sudden, revealing searchlight into obscure recesses, hitherto undivined. He will row out over that great ocean of material, and lower down into it, here and there, a little bucket, which will bring up to the light of day some characteristic specimen, from those far depths, to be examined with a careful curiosity.

Forget reaction times: the Prose has it. The Victorians were (probably, and only some of them) cleverer than us.

The Victorians were cleverer than us!

We keep hearing that people are getting brighter, at least as measured by IQ tests. This improvement, called the Flynn Effect, suggests that each generation is brighter than the previous one. This might be due to improved living standards as reflected in better food, better health services, better schools and perhaps, according to some, because of the influence of the internet and computer games. In fact, these improvements in intelligence seem to have been going on for almost a century, and even extend to babies not in school. If this apparent improvement in intelligence is real we should all be much, much brighter than the Victorians.

Although IQ tests are good at picking out the brightest, they are not so good at providing a benchmark of performance. They can show you how you perform relative to people of your age, but because of cultural changes relating to the sorts of problems we have to solve, they are not designed to compare you across different decades with say, your grandparents.

Is there no way to measure changes in intelligence over time on some absolute scale using an instrument that does not change its properties? In the Special Issue on the Flynn Effect of the journal Intelligence Drs Michael Woodley (UK), Jan te Nijenhuis (the Netherlands) and Raegan Murphy (Ireland) have taken a novel approach in answering this question. It has long been known that simple reaction time is faster in brighter people. Reaction times are a reasonable predictor of general intelligence. These researchers have looked back at average reaction times since 1889 and their findings, based on a meta-analysis of 14 studies, are very sobering.

It seems that, far from speeding up, we are slowing down. We now take longer to solve this very simple reaction time “problem”.  This straightforward benchmark suggests that we are getting duller, not brighter. The loss is equivalent to about 14 IQ points since Victorian times.

So, we are duller than the Victorians on this unchanging measure of intelligence. Although our living standards have improved, our minds apparently have not. What has gone wrong?

You can get more details from Dr Michael Woodley (M.A.WoodleyPhD@gmail.com)

I will post more about this work, but a good start is to look at my previous post "Can I have a reaction?"

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.

The Daily Mail covers Were the Victorians cleverer than us?

http://www.dailymail.co.uk/sciencetech/article-2323944/Were-Victorians-cleverer-Research-indicates-decline-brainpower-reflex-speed.html

The Daily Mail website had 105 million readers in August 2012, This put it in No 1 position, ahead of even the BBC News website. Getting a mention is a guarantee of a large readership in the English speaking globe. The left hand and wider column contains the main news stories, while the narrower right hand column contains the female stories. 

The Woodley et al paper was reported in the main section. In terms of thoroughness, phrases, pictures and column inches, it was superior to The Daily Telegraph. The Daily Mail spoke of REVERSE selection, and gave Darwin, Faraday and Babbage as exemplars of Victorian genius, and in a flash of inspiration illustrated the era's inventiveness with the differential calculating machine, the grandfather of computational devices.

A grand day out for Woodley, te Nijenhuis and Murphy.

The Telegraph covers the Victorians were smarter than us story

http://www.telegraph.co.uk/science/science-news/10053977/The-Victorians-were-smarter-than-us-study-suggests.html

Psychological Comments broke the story first, but it is good to see main stream media covering intelligence research, in a brief but accurate piece.

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.

A response to two critical commentaries on Woodley, te Nijenhuis & Murphy (2013)

Michael A. Woodley, Jan te Nijenhuis, & Raegan Murphy

Our study on the lowering of intelligence has drawn massive attention from the media, with headlines from Brazil to Vietnam. Also thousands of reactions were posted on blogs, including two highly relevant critical comments on the blogs of Scott Alexander and HBD Chick. We give a response in this post. We are also pleased that our paper in Intelligence is starting a scientific discussion on the lowering of intelligence.

Alexander (2013) advances the argument that Galton’s sample is unrepresentative of the population of Victorian London, and may be heavily skewed towards those with high-IQ and faster reaction times (RTs) owing in part to the fact that Galton charged a small fee to those wishing to participate in his data collection exercise. Hence, these studies should not be used as the basis for comparison with more modern studies, which, it has been argued are relatively far more representative in many cases of the populations from which they are drawn. We show here that this argument is wrong.

HBD Chick (2013) has advanced a second argument to the effect that Galton’s sample, and other contemporaneous 19^th century studies (i.e. Ladd & Woodsworth, 1911; Thompson, 1903) represent ethnically homogeneous samples in comparison with more modern ones, which are obviously less homogeneous. Given the existence of ethnic-group differences in reaction time (RT) means (i.e. Jensen, 1998), this is proposed as a cause of the substantially depressed means in current-era studies, thereby undercutting our conclusion that RT has become slower for the general population (HBD Chick, 2013). We show here that this second argument is wrong in as much as changing population composition cannot account for the preponderance of the observed secular trend.

In addressing the first argument, the seminal paper of Johnson et al. (1985) which constitutes the source of Galton’s simple visual RT data employed in both our study and that of Silverman (2010), contains excellent data on the socio-economic and occupational diversity of the relevant subset of Galton’s exceptionally large sample (N around 17,000 individuals, 4838 [or 30%] of whom were included in Johnson et al’s study). The paper states that “… a sizable portion of Galton’s sample consists of professionals, semi-professionals, and students. However … all socioeconomic strata were represented” (p. 876). As can be seen in Tables 10 and 11 (pp. 890-891), the male cohort could be split into seven socioeconomic groups (Professional, Semi-professional, Merchant/Tradesman, Clerical/Semiskilled, Unskilled, Gentlemen [aristocracy] and Student or Scholar). For females, there were six socioeconomic groups represented in the data (Professional, Semi-professional, Clerical/Semiskilled, Unskilled, Lady [aristocracy] and Student or Scholar). In both the male and female sample the modal group appears to be the Student or Scholar category; in both cases these groups exhibit the largest Ns – 1657 in the case of 14-25 year old males, and 297 in the case of equivalently aged females. The second- and third-largest groups amongst the males of equivalent age were Clerical/Semiskilled (N=425) and Semi-professional (N=414). This is basically true of the female sample also, with Semi-professional being the next largest group after Student or Scholar (N=104) and Clerical/Semiskilled comprising the third largest group (N=47). Whilst it is obviously true that the sample is skewed towards Students or Scholars in both cases, individuals from these lower-middle/upper-working class occupations combined (see p. 888 in Johnson et al., 1985; for a full description of how these occupational categorizations correspond to employment type), make up a respectable proportion of the 14-25 year old samples also (>30% in the case of the males, and >30% in the case of the females). It is important to note that according to Johnson et al (1985) many of the students would have been pupils at schools accompanied by teachers on day-trips to Galton’s laboratory at the Kensington Museum. However, a fundamental point is that Silverman’s (2010) study uses only data for those aged 18-30 (see Table 1, p. 41 in Silverman [2010] for full details of this subsample), hence is quite unlikely to have been nearly as skewed towards school-aged students relative to the sample as a whole, which included a much larger range of ages.

A careful reading of Silverman (2010) will reveal that he was cognizant of precisely how much socioeconomic diversity was present in Galton’s dataset. Accordingly he was very careful to include only samples that would broadly match one or more of the categories in Galton’s dataset (see: Silverman, 2010, Table 2, pp. 42-43 for full disclosure of the sample background characteristics). One advantage of Silverman’s care and meticulous attention to detail is that it permits us to make like for like comparisons with specific socioeconomic and occupational groups in Galton’s data, thus we can directly test the claims of Alexander (2013). Concerning the post-Galton studies Silverman included five student samples, two of which date from the 1940s (Seashore et al. 1941), and the remaining three of which date from the 1970s to the 2000s (mean testing year = 1993; Brice & Smith, 2002; Lefcourt & Siegel, 1970; Reed et al., 2004). These can be compared with the combined Galton and Thompson 19^th-century student data in a three-way comparison as follows:          

Comparison involving male students          Difference in mean N-weighted RT means

19^th-century students vs. 1940s-era students                          +16.8 ms (183.2-200 ms)

19^th-century students vs. ‘modern’ students                           +74.2 ms (183.2-257.4 ms)

1940s-era students vs. ‘modern’ students                              +57.4 ms (200-257.4 ms)

The difference between the 19^th century and the ‘modern’ male students is very similar to the meta-regression-weighted increase in RT latency between 1889 and 2004, estimated on the basis of all samples included in the meta-analysis (81.41 ms). Silverman also included data from other socioeconomic groups. For example the study of Anger et al. (1993) included a combined male + female sample of 220 postal, hospital and insurance workers from three different US cities. These occupations clearly fall into the Clerical/Semiskilled and Semiprofessional groups identified in Galton’s study. For both males and females in Galton’s data, the N-weighted RT mean for these two groups is 185.7 ms, the N-weighted average amongst the participants in the study of Anger et al. (1993) was 275.9 ms. This equates to a difference of 90.2 ms between the 19^th century and 1993. Again, this is not dissimilar to our meta-regression-weighted estimate of the cross-study increase in RT latency (81.41 ms).

The results of these broadly socioeconomically- and occupationally-matched study comparisons therefore imply an additional degree of robustness to the findings of our more statistically involved analysis of the overall secular trend. Furthermore, this evidences Silverman’s contention that as an aggregate, the ‘modern’ studies have broadly equivalent representativeness to the subset of Galton’s data employed in his and our own analyses. Alternatively we could state that neither Galton’s nor Silverman’s data are truly fully representative of any population, however they are both ‘biased’ in their sampling towards broadly similar groups.

We continue with the second concern, i.e. the lack of strict ethnic matching criterion, hypothesized to lead to substantially depressed RT means in current-era studies. Ethnic-group differences in performance on various elementary cognitive tasks have been documented and are to be expected (i.e. Jensen, 1998). Substantial changes in terms of the ethnic composition of test-takers would however be needed in order for the magnitude of change to be solely or even substantially a consequence of this process. This is assuming of course that within and between ethnic-group comparisons in terms of RT produce proportional results.

RT is related to g via mutation load (as measured using fluctuating asymmetry; Thoma et al., 2006). Mutation load is therefore likely to be a general source of individual differences in cognitive functioning within populations (Miller, 2000), but not between them (e.g. Rindermann, Woodley & Stratford, 2012), hence there is no good reason to expect ethnic-group differences in RT means to be meaningfully comparable to within-group differences in terms of proportionality (consistent with this is the observation that on simple RT these differences whilst present are actually quite small; Jensen, 1993; Lynn & Vanhanen, 2002, pp. 66-67). So, indeed ethnically heterogeneous samples will exhibit slightly slower or even faster reaction times (depending on the populations and proportions involved), however the current proportions of groups exhibiting slower simple RT means to Whites in Western countries are simply too small, and the group-differences too slight to have had a substantial effect.

It is also worth noting that the weighted mean of our modern (post-1970) aggregated estimate (264.1 ms) is actually less than Jensen’s (1993) finding of a 347.4 ms mean of simple visual RT amongst a sample of 582 White US pupils described as being of European descent, and also Chan and Lynn’s (1989) finding of a 371 ms simple RT mean for over 1000 White British school children in Hong Kong. It must be noted however that these studies were conducted on young children – simple RT shortens until the late 20’s when full neurological maturation is achieved (e.g. Der & Deary, 2006), hence Jensen and Chan and Lynn’s estimates are likely to be underestimates of the adult simple RT means of these Whites, which may be somewhat closer to our sample mean of ‘modern’ (mostly White) populations in actuality.

We would like to thank Scott Alexander and HBD Chick for their interest in our study, and for their commentaries, however the counter-arguments, whilst thought-provoking, do not appear to withstand scrutiny. We must therefore conclude that the secular slowing of simple reaction time between the closing decades of the 19^th century and the opening one of the 21^st has had little to do with sampling issues.

References

Alexander, S. S. (2013). The wisdom of the ancients. Slate Star Codex. URL: http://slatestarcodex.com/2013/05/22/the-wisdom-of-the-ancients/ [retrieved on 24/05/13]

Anger, W. K., Cassitto, M. G., Liang, Y.-X., Amador, R., Hooisma, J., Chrislip, D. W., et al. (1993). Comparison of performance from three continents on the WHO-recommended

Neurobehavioral Core Test Battery (NCTB). Environmental Research, 62, 125–147.

Brice, C. F., & Smith, A. P. (2002). Effects of caffeine on mood and performance: A study of realistic consumption. Psychopharmacology, 164, 188–192.

Chan, J., & Lynn, R. (1989). The intelligence of six year-olds in Hong Kong. Journal of Biosocial Science, 21, 461-464.

Der, G., & Deary, I. J. (2006). Age and sex differences in reaction time in adulthood: Results from the United Kingdom Health Lifestyle Survey. Psychology and Aging, 21, 62–73.

HBD Chick. (2013). We’re dumber than the Victorians. HBD Chick. URL: http://hbdchick.wordpress.com/2013/05/22/were-dumber-than-the-victorians/ [retrieved on 24/05/13]

Jensen, A. R. (1993). Spearman’s hypothesis tested with chronometric information-processing tasks. Intelligence, 17, 47-77.

Jensen, A. R. (1998). The g factor: The science of mental ability. Westport, CT:

Praeger.

Johnson, R. C., McClearn, G., Yuen, S., Nagosha, C. T., Abern, F. M., & Cole, R. E. (1985). Galton's data a century later. American Psychologist, 40, 875–892.

Ladd, G. T., & Woodworth, R. S. (1911). Physiological psychology. New York, NY: Scribner.

Lynn, R., & Vanhanen, T. (2002). IQ and the Wealth of Nations. Westport, CT: Praeger.

Miller, G. F. (2000). Mental traits as fitness indicators: Expanding evolutionary psychology’s adaptationism. Annals of the New York Academy of Sciences, 907, 62–74. 

Reed, T. E., Vernon, P. A., & Johnson, A. M. (2004). Sex difference in brain nerve conduction velocity in normal humans. Neuropsychologica, 42, 1709–1714.

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

Seashore, R. H., Starmann, R., Kendall, W. E., & Helmick, J. S. (1941). Group factors in simple and discrimination reaction times. Journal of Experimental Psychology, 29, 346–394.

Silverman, I. W. (2010). Simple reaction time: It is not what it used to be. The American Journal of Psychology, 123, 39–50.

Thoma, R. J., Yeo, R. A., Gangestad, S., Halgren, E., Davis, J., Paulson, K. M., & Lewine, J. D. (2006). Developmental instability and the neural dynamics of the speed-intelligence relationship. Neuroimage, 32, 1456-1464.

Thompson, H. B. (1903). The mental traits of sex. An experimental investigation of the normal mind in men and women. Chicago, IL: The University of Chicago Press.

Woodley, M. A., te Nijenhuis, J., & Murphy, R. (2013). Were the Victorians cleverer than us? The decline in general intelligence estimated from a meta-analysis of the slowing of simple reaction time. Intelligence. doi:10.1016/j.intell.2013.04.006 

ORIGINAL PAPER: "A response to Prof Rabbitt – The Victorians were still cleverer than us" by Woodley, te Nijenhuis and Murphy

A response to Prof Rabbitt – The Victorians were still cleverer than us

By Michael Woodley, Jan te Nijenhuis, and Raegan Murphy

Professor Rabbitt has reacted to our interpretation of the secular trend in simple reaction time speeds first detected by Silverman (2010), and validated by us (Woodley, te Nijenhuis & Murphy, 2013). We would like to thank professor Rabbitt for his interest in our work and for being one of the first to substantially contribute to the scientific discussion that was started by our paper. Rabbitt makes several interesting points of criticism – here we will show however that these do not constitute sufficient grounds to reject the reality of the secular slowing of simple reaction time.

Firstly, Rabbitt argues that the level of inaccuracy in instrumentation designed to measure simple reaction time was historically quite high, especially in the pre-1970’s era where he argues that it was on the order of 100 or so ms. Rabbitt then goes on to state paradoxically that a reading of 200 ms might therefore fall between 200 and 299 ms, which assumes a bias of 99 rather than 100 ms, and also that the instrumentation would consistently ‘round down’ reaction time estimates. In actuality a bias of 100 or so ms would yield an average bias of 50 ms either way, assuming that the error due to bias was normally distributed, and that there was no tendency for biases to be skewed in one direction rather than in the other. Rabbitt does not provide any evidence for such a tendency towards rounding down – he merely states this as a fact apparently based on personal experience with pre and post-1970’s instrumentation. 

  

Secondly, Rabbitt argues that method variance across studies employing different instrumentation makes direct mean-wise comparison of results problematic. He illustrates this via reference to the use of warning signals along with the signal intensities, durations and rise-times of different light sources (such as bulbs, fluorescent tubes, LEDs, computer monitors, etc), and also with respect to response keys that might have been non-uniformly ‘sticky’ across different apparatus.

Thirdly, Rabbitt argues that the presence of only two data points from the Victorian era in our studies means that we can “… leave aside an important question whether there is any sound evidence that creativity and intellectual achievements have declined since the Great Victorian Flowering”.  

In addressing the first of Rabbitt’s claims, we are skeptical about the suggested level of inaccuracy in pre-70’s era instrumentation (such as Galton’s apparatus and the electro-mechanical Hipp chronoscope). True millisecond resolution in measurement had been achieved far earlier than Rabbit claims, namely in 1908 (Haupt, 2001), with instruments prior to that being typically accurate to at least a hundredth of a second. It is not obvious why decent resolution (perhaps on the order of a hundredth of a second) would not have been within the grasp of someone of Galton’s mental stature and notoriously obsessive attention to detail (Rose & Rose, 2011). His apparatus was described in an 1889 paper and employed a half-second pendulum, whose duration could be estimated using very basic mathematics. Its release occurred concomitantly with the concealing of a white paper disk, which functioned as the stimulus - depressing a key facilitated its capture, registering the reaction-time score. Similarly the much more sophisticated Hipp chronoscope, with its electro-mechanical clutch-based mechanism was capable of true millisecond resolution (Haupt, 2001). The issue of true millisecond resolution is at any rate rendered moot in light of the fact that we are dealing with the means of a large number of individuals measured by Galton and others in multi-trial type experiments. Resolutions of hundredths of a second would seem to suffice in such samples (Haupt, 2001).

These observations aside, there is a far more substantive problem with Rabbitt’s primary claim, namely that, even assuming a normally distributed 100 ms level of inaccuracy, the preponderance of pre-1970 studies still reveal upper bound means for simple reaction time that are shorter in duration than the sample size weighted ‘true millisecond resolution’ mean of post-1970 studies.  

        

Table 1

Reaction time means for five pre-1970 studies used in Woodley et al. (2013) along with estimates of error due to sub-100 ms measurement imprecision

Reported mean (combined and N-weighted for the sexes where available)	Error range assuming 50 ms either way
184.3 ms    (Galton, 1890’s)	134.3-234.3 ms
208 ms       (Thompson, 1903)	158-258 ms
197 ms       (Seashore et al., 1941)	147-247 ms
203 ms       (Seashore et al., 1941)	153-253 ms
286 ms       (Forbes, 1945)	236-336 ms

Weighted mean of post-1970 studies = 264.1 ms

Based on Table 1, assuming a normally distributed 100 ms inaccuracy, the upper estimate falls below the post-1970 ‘true millisecond resolution’ mean in four out of five cases (the exception being the study of Forbes, 1945). The cumulative odds of this being a chance result can easily be calculated. Let us assume a 50% chance that the instruments would produce a mean value whose upper-bound estimate falls above that of the post-1970’s study. The odds of four studies producing consecutive means whose values are lower is equal to 0.5*0.5*0.5*0.5, or 6.25%. In other words, the probability that this is a chance finding is small. If we add to this the systematic review of Ladd and Woodsworth (1911), which found a mean for 19^th- and early 20^th-century samples of 192 ms, and whose hypothetical upper mean also falls below the weighted post-1970 mean (242 ms), the cumulative odds of this being a chance finding fall to 3.12%. 

   

Secondly, and again assuming high inaccuracy, why are the results of the pre-1970's studies likely to be overestimates rather than underestimates of the true values? Let’s look at the sources of bias that Rabbitt describes. Sticky keys might require more force to in order to register a result. This was more likely to have been a problem in the case of earlier studies employing cruder instruments, such as mechanical or hybrid electro-mechanical apparatuses, rather than computer-based ones, for example. This suggests that the bias would have been in the opposite direction for earlier studies to that described by Rabbitt. Sticky keys would necessarily lengthen rather than shorten reaction time estimates. Long-duration visual signals, and also ones that are more intense and exhibit rapid rise-times typically elicit faster (or maximal) reaction times (Kosinski, 2012). Galton’s apparatus used a purely mechanical signal in the form of a paper disk, which could be made to disappear via the operation of levers, thus triggering the subject to depress a key and halt the swing of a half-second pendulum. The signal duration was therefore indefinite – persisting until the point at which the apparatus would be reset. It is hard to argue against the high visibility of such a signal either, assuming a well-lit laboratory. Subsequent studies employing the Hipp chronoscope such as Thompson (1903) and the studies described in Ladd and Woodsworth (1911) would have employed light sources. Thompson (1903) for example employed a Geissler tube suspended against a black background which was reported as producing a “flash of pale purple light” that was “thrown out sharply” (p. 8). Geissler tubes are plasma-discharge or fluorescence-based illumination sources. Fluorescent light sources exhibit extremely rapid rise-times compared to filament-based incandescent bulbs, for example (Sivak, Flannagan, Sato, Traube & Aoki, 1993).       

Whilst the issue of signal duration in these early studies employing light sources as stimuli is indeed problematic, the suboptimal tendency is towards shorter duration signals (i.e. brief flashes), which would lengthen rather than shorten reaction time estimates. It is long-duration visual signals that permit the recovery of accurate maximal reaction time latencies (Kosinski, 2012). Once again, any measurement error in these earlier instruments would tend to skew the estimates towards higher rather than lower latencies.

What of the issue of warning signals? As Silverman (2010, p. 41) reports, there is very little evidence that warning signals actually make a difference to recorded reaction time latencies, especially when the ensuing stimulus is unpredictable, as was the case in all studies employed in our and Silverman’s analyses. It is unlikely that Galton utilized a warning system in his single person-single trial study. Thompson (1903), however, did use an audio warning system in her study involving multiple trials per person. The difference in the means between the two studies is extremely small (18.7 ms), and in the opposite direction to that predicted by the theory that the presence of a warning signal reduces the latency of reaction time means. This strengthens Silverman’s conclusion that employing warning signals makes little difference.

We agree with Rabbitt, and also Jensen (2011), who both argue that method variance between studies can be a substantial problem when it comes to comparing between different studies, especially those using different instrumentation. However, Rabbitt seems to have missed the point of the meta-analytic nature of our own and Silverman’s study. Indeed, the study of Silverman (2010) set out to explicitly address the issue of method variance using a stringent set of seven inclusion rules (p. 41) coupled with a detailed meta-analytic search. The rules were selected on the basis that all studies included in the comparison set should be as closely matched with respect to Galton’s study on as many dimensions as possible. The stringency of these rules means that method variance across studies is substantially reduced, however the trade-off is that the number of potentially usable studies is also massively reduced. Our meta-regression ultimately demonstrates the power of a properly conducted meta-analysis in this regard as we found no significant role for moderators in explaining the secular trend towards increasingly latent simple reaction time performance. There is scatter around the regression line, but that is exactly what meta-analytical theory predicts. All data points being on or very close to the regression line is an extremely unlikely outcome for a meta-analysis (see Hunter & Schmidt, 2004).   

Finally, what of the issue of sound evidence for the greater accomplishments of 19^th-century Western populations relative to contemporary ones? This is an important issue that has been addressed quantitatively using historiometry, which is the historical study of human progress or individual personal characteristics, using statistics to analyze references to geniuses, their statements, behavior and discoveries in relatively neutral texts (Simonton, 1984). Historiometric research into innovation rates and the lives and accomplishments of eminent individuals (geniuses) has shown that the per capita rate (i.e. events per billion of the population per year) of significant innovation and also geniuses in science and technology peaked in the late 19^th century, after a long period of increase. Throughout the 20^th century there was a decline (Huebner, 2005; Murray, 2003).

What is a significant innovation? It is simply one that is conspicuously different from anything that came before – so much so that multiple encyclopedists and compilers of inventories of innovation are likely to independently note it. Examples include the development of the plough, the steam engine, splitting the atom and putting a man on the moon. The iPhone 5 is not a significant innovation in comparison with its earlier incarnations by contrast, and is unlikely to be considered as such by contemporary historians of science and technology. Similarly geniuses can be rated via the degree to which these same sources reference them. The use of a ‘convergence’ criterion based on prominence across encyclopedias not only allows us to reasonably quantify the frequencies of significant innovation and geniuses throughout the history of civilization, but it also allows us to rank those same innovations and individuals in terms of importance. This historiometric technique, like many extremely useful ideas, has its origins in the writings of Galton (1869).

In conclusion, whilst Rabbitt’s criticisms are interesting, they are clearly insufficient grounds for rejecting the central claims made in our paper – namely that the secular trend in increasing simple reaction time latency is robust and translates into a decline of -1.23 IQ points per decade or -14.1 points since Victorian times.

References

Forbes, G. (1945). The effect of certain variables on visual and auditory reaction times. Journal of Experimental Psychology, 35, 153–162.

Galton, F. (1869). Hereditary genius. London, UK: Macmillan Everyman's Library.

Galton, F. (1889). An instrument for measuring reaction time. Report of the British Association for the Advancement of Science, 59, 784–785.

Haupt, E. J. (2001). Laboratories for experimental psychology: Gottingen’s ascendancy over Leipzig in the 1890s. In: Rieber, R. W., & Robinson, D. K. (Eds.), Wilhelm Wundt in history. The making of a scientific psychology. (pp. 205-250). New York, NY: Kluwer Academic. 

Huebner, J. (2005). A possible declining trend for worldwide innovation. Technological Forecasting and Social Change, 72, 980–986.

Hunter, J. E., & Schmidt, F. L. (2004). Methods of meta-analysis (2nd Ed.): Correcting error and bias in research findings. Thousand Oaks, CA: Sage.

Jensen, A. R. (2011). The theory of intelligence and its measurement. Intelligence, 39, 171–177.

Kosinski, R. J. (2012). A literature review on reaction time. http://biae.clemson.edu/bpc/bp/lab/110/reaction.htm

Ladd, G. T., & Woodworth, R. S. (1911). Physiological psychology. New York, NY: Scribner.

Murray, C. (2003). Human accomplishment: The pursuit of excellence in the arts and sciences, 800 BC to 1950. New York, NY: Harper Collins.

Rose, H., & Rose, S. (2011). The legacies of Francis Galton. The Lancet, 377, 1397.

Simonton, D. K. (1984). Genius, creativity and leadership: Historiometric inquiries. Cambridge, MA: Harvard University Press.

Sivak, M., Flannagan, M. J., Sato, T., Traube, E. C., & Aoki, M. (1993). Reaction times to neon, LED, and fast incandescent brake lamps. The University of Michigan Transportation Research Institute, Report Number. UMTRI-93-37.

Seashore, R. H., Starmann, R., Kendall, W. E., & Helmick, J. S. (1941). Group factors in simple and discrimination reaction times. Journal of Experimental Psychology, 29, 346–394.

Silverman, I. W. (2010). Simple reaction time: It is not what it used to be. The American Journal of Psychology, 123, 39–50.

Thompson, H. B. (1903). The mental traits of sex. An experimental investigation of the normal mind in men and women. Chicago, IL: The University of Chicago Press.

Woodley, M. A., te Nijenhuis, J., & Murphy, R. (2013). Were the Victorians cleverer than us? The decline in general intelligence estimated from a meta-analysis of the slowing of simple reaction time. Intelligence. Doi:10.1016/j.intell.2013.04.006

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

                                                                                                                                 

Question time #LCI14

 

Would you like to ask some researchers questions about intelligence?

The sorts of topics could be: Spearman's Hypothesis examined for primate cognitive comparisons; Why don’t Northeast Asians win Nobel prizes?; The Roma: a Balkan underclass; Science and its discontents; The evolution of racial differences in intelligence, in psychopathic personality and sporting abilities; Sex differences in intelligence; Polygenic selection and human evolution; the intelligence of the Victorians; Understanding heritability estimates; the General Factor of Personality, Dysgenic trends in simple reaction times in Scotland and Sweden; Immigrant attainments in Denmark; cognitive ability in Mexico; g in dogs.

Leave your question as a comment on this blog, and I will try to get an individual researcher to reply to you, either directly or through me. If you favour brevity, then tweet me your question.

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.

Steve Sailer’s reaction times, his driving record and his intelligence

In yet another engaging and meditative post, Steve Sailer has given us his personal view on his driving errors, reaction times, and intelligence. http://www.isteve.blogspot.co.uk/2013/05/were-victorians-cleverer-than-us.html

With commendable honesty, he shows that he is fully aware that we should not keep ourselves “above the audit”. Every observer is also observable, and must submit to enquiry. Not everyone knows that, or behaves as if it were true.

Like Steve, I depend on the kindness of strangers to make allowance for my driving errors, and I remember clearly my failures to scan the road both ways at apparently quiet junctions. I have (mostly) got rid of the delusion that I am an above average driver. Why does this view prove so popular? One very strong reason is that the distribution of driving errors does not conform to the standard normal curve. Gigerenzer covers this in his mini-chapter “Why most drivers are better than average” on page 214 of his book “Reckoning with risk”. (This book can be quoted to advantage on virtually any occasion).

Most people drive pretty safely. (They avoid errors, but also recall their prudent reactions with pride and attribute their errors to a temporary lapse, which they tend to forget). A minority of drivers keep getting into trouble. This includes many young men, a very few young women, those of any age who drink heavily, those who allow themselves to be distracted by phones and fellow passengers, and some who just cannot control their speeds. In the spirit of Lady Bracknell who admitted: “I myself am peculiarly susceptible to draughts” I should confess that I am peculiarly susceptible to open roads in bright sunshine, though that is not a frequent temptation in England. Mind you, on the sunny road back to London last evening under the dappled, yew-tree-tunnelled shade of Salisbury plain, with not a car in sight, none of these prudent observations were uppermost in my mind.

Anyway, back to the distribution of errors: as a result of this dangerous minority, rather than 50 percent of drivers being above average, the true figure is probably that 63 percent are above the modal accident rate, and are justified in saying that they are, in the common parlance, “above average drivers”. Skewed distributions are difficult to describe in ordinary language, but depict a familiar social problem: that of accounting for behavioural minorities. (It takes us away from the main argument, but this is also true of the minorities who have more than 50 sexual partners, rather than the more usual, contemporary 10).

When I discussed this finding with driving behaviour psychologists some years ago (the driving, not the sex) one gave me an evidence-based and crushing reply: he sent me the self-evaluations he had collected from learner drivers who had only just passed their driving test. This is the period in which there is a sharp spike in accidents and deaths, partly due to sheer inexperience, partly due to showing off to passenger friends after a drinking party at night. These novice drivers habitually rated themselves as being 7 or 8 out of 10, when in fact they were at that stage 3 or 4 out of 10.

This is yet another example of the Dunning-Kruger syndrome: over-confidence and under-competence, a thoroughly lethal combination. It is a cognitive bias in which the unskilled suffer from illusory superiority, and lack the competence and self-reflection to acknowledge their deficiencies. This is a very common disorder, and seems to be inversely related to self-esteem and intelligence. Brighter people note their errors, note their brighter competitors, and are grimly aware of all the stuff they ought to know, but haven’t got round to reading yet (they monitor the external world). Less bright people revel in their accomplishments. They have delusions of adequacy (they monitor their internal world). It is not the purpose of this blog to encourage public abuse, but after being subjected to any sustained burst of self-confident nonsense one is justified in muttering, very quietly to one’s self “Dunning-Kruger syndrome”. I append the reference as a public service to aggrieved citizens who might otherwise be tempted to violence.

Kruger, Justin; David Dunning (1999). "Unskilled and Unaware of It: How Difficulties in Recognizing One's Own Incompetence Lead to Inflated Self-Assessments". Journal of Personality and Social Psychology 77 (6): 1121–34.doi:10.1037/0022-3514.77.6.1121. PMID 10626367. CiteSeerX: 10.1.1.64.2655

Now to Steve Sailer’s reaction times. As already discussed in this blog (Can I have a reaction  http://drjamesthompson.blogspot.co.uk/2013/02/can-i-have-reaction.html) you should google “BBC reaction time sheep test” and then all of us can get ourselves on a common baseline. Ignore any blogger who does not post their reaction time results. Equally, demand reaction times from would-be commentators on your blogs. (Note that there are artefacts: my standard laptop response key gives poorer results than a new wireless mouse, so if this really bugs you, buy the latest and most sensitive response key you can find).

As Jensen was at pains to point out, reaction times contain two elements: thinking time and movement time. In ordinary life the two are confounded. Faced with an obvious threat, if you keep both of these short you keep alive. In more tricky situations with various options to consider, thinking time becomes the great discriminator, and movement time less significant.

Perhaps Steve is right that Jensen complicated reaction times too much. He was attracted by the beauty of Hick’s Law (speed plotted against the log2 of decision options) with which his results fitted quite well. Ian Deary, on the other hand, finds that simple reaction times predict lifespan, or at least take out a good chunk of the IQ/lifespan variance, suggesting that a common pathway gives us health, reaction speed and intelligence, to varying degrees.

Sport, as I understand it, often involves throwing or hitting balls. Do not ask me why. As far as I am concerned, balls have never done me any harm, particularly when left alone. Propelled at velocity they can be dangerous. For some reason schools pick on serious readers and interrupt their studies by taking them outside and getting them to catch these objects. The trick, for those serious readers who can see the flying object in the first place, is to compute the balls’ parabolic trajectory and the place and time of landing, and thus accelerate themselves into the place where it is most likely to land just at the moment it does so.

Rather than attempting any of this, it would be simpler to note that reaction times, whilst showing a positive correlation, are not very strongly related to measures of intellect. Steve is not the first of my clever readers I have had to reassure on this point.

Steve makes a personal claim: “I'm a reasonably intelligent person”. Claims of this sort are not allowed in England, so I can only look at this American remark with bemusement and envy. However, according to the Dunning-Kruger effect, we cannot take such self-assessments at face value. It is pointless to ask Steve for his IQ measurements, since the intelligence quotient is a summary of a sample of intellectual tasks. It does not have a reified status. It is a predictor (one of the best we have, out of a rather weak bunch) but it is not “that which must be predicted”.   

A detailed look at the corpus of his postings, his analysis of data, responses to arguments and so on confirms his likely high intelligence in the usual meaning of that term: “a very general mental capability that, among other things, involves the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly and learn from experience. It is not merely book learning, a narrow academic skill, or test-taking smarts. Rather, it reflects a broader and deeper capability for comprehending our surroundings “catching on,” “making sense” of things, or “figuring out” what to do” (Gottfredson 1994). He also shows an interest in sports, but that is permissible in persons who are otherwise of good character.

Steve makes two additional intelligence-related claims: “There are two intellectual areas where I have very fast reflexes”.

The first area is being fast to get the joke in a movie. I agree that this can be a great, but it is a lonely skill. It leads me to suggest a new IQ test. Skip movies which often have to spend time setting up the context. Take a selection of xkcd.com comics and measure the time between exposure and laughter. Failure to laugh at any three in a row gives you a beautifully embossed certificate of Failure, and a quick exit from the test. The items could be ranked in terms of a priori intellectual complexity, which would be a pleasurable task in itself, and then we could have a good linear scale comprehension test, admittedly rather slanted towards the upper right hand side of the bell curve. (In the spirit of further personal disclosure, today I came across an old copy of the Alice Heim AH5 test for university students, which was used in the 1960s. I can claim to have got a B in this test aged 19, though I doubt I could do that again without resting beforehand for several days. Have a look at some of the items if you can, without breaking copyright).

The second area is Quiz shows involving buzzers. This is a real intelligence test. Anyone who did not test their buzzer before participating fails! Other than that, “first to the buzzer” is the key feature of University Challenge on BBC2, with the proviso that if your answer is wrong ten points go to the other side. Speed matters in a quiz, but speed of thinking matters even more in real life, because faster processors are required to solve harder problems.

Steve says that he “doesn’t get reaction times” but of course he does, it is simply that he knows they are a poorer test of intellect than even something simple like digit span or a ten word vocabulary test. Whilst Steve is probably right about contemporary life, those who belittle reaction time measures are probably wrong about our hunter-gatherer past. In that era one presumes that reaction times were often a matter of life or death. Hence, it might be simplest to keep contemporary reaction time studies simple, and only administer one trial, with minimal warning, so that the test approximates most closely to real life. To my surprise I survived a French driver on a winding hillside road at dusk in the South of France some weeks ago, and was very pleasantly surprised by the speed with which I swerved to avoid him, my passengers less so.

Disclaimer: Some of my above statements are immodest. Modesty about one’s capacities is not only polite, but very probably has high survival value.