Back in March, I wrote about a study that was widely touted as showing that catching Covid lowers your IQ. The study found that individuals who’d had symptoms for more than 12 weeks scored about 6 points lower than those who hadn’t caught the virus. Even individuals who’d had an asymptomatic infection, the study found, scored about 2.5 points lower than those who’d never had one.
However, I was sceptical that these findings were explained by Covid having a large negative impact on cognitive ability.
The authors didn’t actually look at change in IQ scores, but rather at the cross-sectional association between Covid infection and IQ scores. Hence their findings could easily be explained by self-selection: people with higher cognitive ability may have been less likely to catch Covid, and may have been less likely to get seriously ill when they did catch it. As evidence, I noted that such people tend to work in professions that had lower risk of exposure to Covid, and tend to be healthier in general.
A new study has confirmed my suspicions: it appears that catching Covid doesn’t lower your IQ after all.
Bas Weerman and colleagues analysed data from the Understanding America Study – an ongoing longitudinal survey with a large sample size that began in 2014. As part of the survey, respondents complete a series of cognitive tests every two years. In March of 2020, they completed a questionnaire about the emerging Covid pandemic, in which they were asked whether they’d ever tested positive for the virus or been diagnosed with the disease by a healthcare professional. Around the same time, they were invited to participate in separate bi-weekly surveys, which also asked about their infection status.
The researchers therefore had data on respondents’ test scores before the pandemic, their infection status during the pandemic, and their test scores after they’d been infected (for those who had). This allowed them to test whether Covid infection was associated with a decline in test scores between the pre- and post-Covid waves of the survey.
Weerman and colleagues began by replicating the finding of the earlier study – that individuals with lower test scores measured before the pandemic were more likely to become infected. They then looked at whether individuals who became infected subsequently scored lower on the cognitive tests, and found they did not. Eight separate measures of cognitive ability were included in the study, and none of them was affected by Covid infection.
Together, these two findings strongly support my interpretation of the earlier study: self-selection is what explains the association between Covid infection and IQ scores. Rather than Covid infection causing lower cognitive ability, it appears that higher cognitive ability caused people not to catch Covid (or to catch the later, milder variants).
All those headlines about Covid making you less intelligent – about even mild infections knocking several points off your IQ – turned out not to be true. Given the media’s general tendency to exaggerate, overhype and sensationalise the threat from Covid, I wouldn’t expect this new study to get nearly as much coverage as the earlier one.
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Here’s a claim that I’d love to be true:
100% of those who instill fear, panic and despondency have declined over the last minute.
In the meantime: Hope, Strength and Tenacity to those who think and judge for themselves!
—“we have a last chance to act.” Oh goody! Where do I sign up?
If only I had quid for every time I’ve read that or similar, I’d be rich as Croesus.
That’s not going to be your last chance for getting quid whenever someone announces a last chance to … !!!
Don’t forget how the climate data was fiddled to show warming where before there had been none:
https://realclimatescience.com/alterations-to-the-us-temperature-record/
The page from the New York Times in 1989 is worth keeping in mind. No warming trend for a hundred years. Since revised to show a warming trend. I’m not sure whether it is politics or religion but it sure isn’t science to keep fiddling the data to get the result they want.
It’s cobblers! I’ve heard all this since cofo in the 70s. There’s just as much if not more life now than then, you don’t get rid of life that easily
I remember when I was a kid, occasionally I really did see men walking about the town wearing sandwich boards proclaiming that “The End Of The World Is Nigh“. Yes, I really am that old.
Thanks to the breakthroughs of science, we’ve come a very long way since then.
Now, international NGO’s, funded by unimaginably rich megalomaniacs, can make the same nutty proclamation all around the world using electronic media.
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The rule of thumb is simply: Whenever someone presents averages of some data which is not different measurements of the same thing (NB: measurements is important here), he’s trying to pull a fast one because averaging is a mathematical algorithm supposed to remove noise, ie, randomly distributed errors, from a set of measurement of the same quantity as each individual measurement is composed of a value part and an error part whose exact values are unknown. That’s solidly undergraduate math.
In this particular case, averaging means that outliers in the original, raw data set end up being evenly distributed over it. For an example, assume there are four species A, B and C and D. A had a 0.1% increase, B a 5% increase, C a 25% decline and D a 2% increase This means the average change will be -5.6%, composed of 1/4 of 0.1 (0.025), 1/4 of 5 (1.25), 1/4 of -25 (-6.25) and 1/4 of 2 (0.5). On average, species declined by 5.6% is a gross misrepresentation of the actual data.
I keep being amazed how shoddily constructed all of this is. One would expect people with that much money and manpower could do a lot better. This leads to two hypothesises about why they cannot:
Something I should have added to the example: The individual contributions of A, B, C and D to the average are: A 0.31%, B 15.58%, C 77.88% and C 6.23%. More than 3/4 of the average come from the change of a single species.
This article is so wrong I stumped up the £5 to comment.
1) The WWF/ZSL do not claim that 69% of Vertebrates Have Declined Over Last 50 Years (whatever that means). Chris was presumably confused by the phrase: “average 69% decline in the relative abundance” in the Executive Summary of the Living Planet report. It is admittedly tricky to know exactly what this means. But the LPI website is clearer.
Here under “common misconceptions about the LPI”:
“The LPI statistic does not mean that 69 per cent of species or populations are declining”
“The LPI statistic does not mean that 69% populations or individual animals have been lost”
The LPI is shows the average rate of change in animal population sizes – something quite different.
2) The Canadian scientists make a good point about the problems in using a geometric mean to represent overall rate of species decline. But Chris left out an important quote:
“Excluding only the 2.4% most-strongly declining populations (354 out of 14,700 populations) reversed the estimate of global vertebrate trends from a loss of more than 50% to a slightly positive growth (Fig. 2). Similarly, excluding 2.4% of the most-strongly increasing populations strengthened the mean decline to 71%.”
They are not claiming there is no problem with biodiversity decline – only suggesting a method that is not so sensitive to extremes. They concluded that decline tends to be concentrated in a relatively few species and areas but this doesn’t mean it is not a serious problem.
“Although the global BHM model reveals considerably more nuance than a geometric mean index, analysing across systems still masked important patterns. When systems were analysed separately…., primary population clusters were strongly declining (θ1 < −0.015) with high certainty (95% credible intervals not overlapping zero) in three systems, all of which occurred in the Indo-Pacific realm (freshwater mammals, freshwater birds and terrestrial birds) ….. This suggests that this region has the highest risk of system-wide declines and should be a conservation priority. By contrast, the primary cluster was increasing with high certainty in seven systems, six of which were in temperate regions. In addition, seven additional systems had strongly declining primary population clusters but with less certainty (95% credible intervals overlapped zero), four of which were amphibian or reptile groups.”
The Finnish scientists were just pointing out that the LPI is no good for measuring abundance – but as it was never intended to do that, it is kind of irrelevant.
The LPI is shows the average rate of change in animal population sizes – something quite different.
As explained in another comment: This is a bullshit metric supposed to give the impression of an strong, overall decline which doesn’t exist.
But Chris left out an important quote:
“Excluding only the 2.4% most-strongly declining populations (354 out of 14,700 populations) reversed the estimate of global vertebrate trends from a loss of more than 50% to a slightly positive growth (Fig. 2). Similarly, excluding 2.4% of the most-strongly increasing populations strengthened the mean decline to 71%.”
That’s from a different part of the text and the quote attached to the graph is correct. Further, really taking everything into account, the outcome is
Here we show, however, that this estimate is driven by less than 3% of vertebrate populations; if these extremely declining populations are excluded, the global trend switches to an increase.
[…]
16 systems contain clusters of extreme decline (comprising around 1% of populations; these
extreme declines occur disproportionately in larger animals) and 7 contain extreme
increases (around 0.4% of populations). The remaining 98.6% of populations across
all systems showed no mean global trend.
—–
That’s from the abstract. Another nice quote from the Discussion section of this paper:
Shifting the message from ubiquitous catastrophe to foci of concern,
also touches on human psychology. Continual negative and guilt-ridden
messaging can cause despair, denial and inaction. If everything is
declining everywhere, despite the expansion of conservation measures
in recent decades, it would be easy to lose hope. Our results identify
not only regions that need urgent action to ameliorate widespread
biodiversity declines, but also many systems that appear to be gener-
ally stable or improving, and thus provide a reason to hope that our
actions can make a difference.
That’s absolutely not the kind of serious problem of the WWF and it calls for targetted, perfectly traditional conservation measures, not global lifestyle changes.
It’s all irrelevant, life will do what it wants!
You can see the Board of Directors of the WWF here.
https://www.worldwildlife.org/about/leadership
There’s a lot of money in all those financial institutions so many of them work for. Is it any surprise they pursue the WEF agenda?
Incidentally, it’s only officially called the World Wildlife Fund in the US and Canada. In the rest of the world it renames itself the World Wide Fund, thus allowing it to use funds for other purposes. It’s also been accused several times of ‘greenwashing’, cosying up to big multi-nationals in exchange for donations, human rights abuses, and the use of paramilitaries.
It’s also worth noting that for very many years its patrons, directing the use of funds to protect rare species, then went off hunting those same wild species. Using donor money to keep their exclusive ‘sport’ going?
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It is good to be sensitive and open to the damage that we do as a species but given the agendas that prevail and owe their existence to pure ruling class survival tendencies we do well to be sceptical. If you weren’t born under a Christmas tree. Don’t talk to me about environmental espoiliation when you haven’t given a monkeys about anything until now.
When I studied Physics and Biology at A-Level 35 years ago, and Physics at University thereafter, I must have missed the sections of the scientific method that told me to first determine what I wanted my research to conclude, then disregard any results that showed anything otherwise. Oh, and the step that told me to simply fabricate (adjust) supporting results if I need to. I think I’m owed a Ph. D. from someone …
Me too! And this approach would have meant getting the PhD after about 9 months or so’s study!