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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Good thought provoking article and it made a lot of sense, where, if only zero & one matter then that is the sum of modern western life where, one (I/ me) only count and all the rest is less than and relative to me.
Is it not closely related to the policy of language manipulation, i.e. changing the meaning of one thing or another, so as to promote it as if it was something else. Perhaps someone will create a new Zero Intelligence Party (ZIP)!
ZIP. awesome.
e^(i pi) + 1 = 0
I think ‘zero’ has its uses when it comes to the C1984 and ‘health savings measures’ as in ‘I am not interested so button it.’
Zero alcohol drinks – that’s almost oxymoronic.
The song “Saved By Zero” by The Fixx comes to mind.
Forget about Net Zero, we need Real Zero.
Considering that our very bodies generate energy with the help of exothermic reactions creating carbon dioxide as waste product, the Gretna is either unusually thick or she must be calling for the extermination of all breathing animals on this planet.
Its the first of your suggestions. She’s obviously missed a lot of school and hasn’t handed any biology homework in, that’s plain to see. I think she is also keen of seeing at least a partial extermination of the human race. Not people like her, you understand. People like us…
ZERO in respect of NET ZERO meant ZERO discussion. —- ZERO questions were ever asked by any MP of any major party as to the cost /benefit. It was simply waved through. ————–When you ask ZERO questions you get ZERO answers. So, for the estimated one and a half trillion quid that this ZERO is costing, what we get in return is the biggest fattest ZERO ever. An astronomical sum of money for ZERO in return. ZERO Benefit to anyone or to the climate. Infact in might even be close to Absolute ZERO
Damn good points. 👍
Great thought provoking piece James. in Scotland our shite recycling QANGO is called Zero Waste Scotland. The idea of zero waste when Sturgeon has just panicked the flock into wearing more masks to “protect the NHS is lunacy on a cosmic level. Maybe to protect it from patients. Zero tolerance is another pile of mince which is used by every shite organisation from councils to car showrooms. It’s about alleged “violence” but thus is usually only violence in the woke/Sussex sense. it’s designed to shut down criticism or complaint and when people get really frustrated they tend to use sweary words or raise their voice. And can be barred/cancelled. Generally the people complaining have zero concern for their customer and zero intention of doing their job. This is often masked by bogus reference to “mental health”, presaging a nice week off for said zero waster.