I recently saw this on Hacker News (https://news.ycombinator.com/item?id=48787625) and I find it pretty convincing. When I ask AI, they are also skeptical about both the effect of CO2 and the quality of the paper you linked. Both ChatGPT and Claude thinks it is overselling the findings.
We’ve been studying the impact of CO2 for decades, at much higher levels than you see in office buildings and have never recorded any cognitive impact (until many thousands of PPM) until the Satish study in 2012 and a handful of other studies that Satish was involved in.
If you think about it for a second these studies can’t be accurate. If they were, you’d see differences on SAT scores of hundreds of points depending on building ventilation. You’d see huge variations between taking the SAT in the springtime when the windows are more likely to be open or in the winter.
You’d expect to see massive performance differences across nearly every metric between regions that use AC vs those that depend on opening windows.
And we do not see anything like that.
The difference between Satish-involved studies and other studies is extreme, too. Their first 2012 study tested levels at 600, 1000, and 2500ppm. In many categories they observed the 2500ppm group receiving “dysfunctional” ratings in their tests. Even their 1000ppm group saw significant drops.
This sparked the panic about CO2 levels that led to people buying CO2 sensors and thinking that not unusual CO2 levels were actually destroying their ability to think. Many conclude that this has been happening all of their lives and to everyone around them who is unaware.
It triggered a lot of follow-up studies. Confusing, some of those (like the Harvard one everyone cites) included Satish, meaning they weren’t independent despite coming from different organizations.
The really interesting thing is that many of the follow-up studies that don’t include Satish have even used CO2 levels much higher than the 2012 study that caused the panic. Here is one I grabbed at random that went all the way up to 15,000ppm and failed to find any significant changes: https://pubmed.ncbi.nlm.nih.gov/29789085/
There was also a lot of CO2 research before Satish come along that failed to find significant effects at these relatively low levels. It has been researched in the contexts of air quality for submarines and space shuttles by militaries and NASA because keeping the crew of those operating optimally is important, clearly.
Interesting, thanks. (There were too many unhinged comments on Hacker News for this post, so I stopped reading them.
At absolute minimum, I think you show that I was incorrect to claim it’s an established fact that CO₂ is harmful for cognition. And anyway, I don’t need that claim, so I’ve changed it to “sometimes claimed to be”.
Still, it’s interesting to debate if cognitive effects exist. I think the paper at the end (done by the Navy) gives very convincing evidence that the huge effects reported by Satish are not real. If you take Table II, the cognitive test results at 15,000 ppm are indeed worse than at 600 ppm results for 6⁄9 tests. But they’re equal for 2⁄9 tests, and actually better for 1⁄9, and the magnitude where they’re better is the largest of all. They find effect sizes between 0.001 and 0.054, which vaguely suggest a small benefit, but none are statistically significant, and they seem to be using a one-sided estimator.
I guess I’d rate my claim as 90% wrong? Some small effect might exist, but there’s no convincing evidence. So thanks again for the correction!
Yeah, Hacker News is really noisy, that’s why I just linked that specific comment. I didn’t actually read the Navy paper (or any paper regarding CO2), so thanks for the additional point.
I don’t know whether cognitive effects exist at reasonable ppms, but it seems like any real effects would be too small to worth caring for optimizing productivity, so I stopped investigating.
Agreed on substance – I started from the same skepticism and remain with it. Caveat just on structure of your argument: the population-level checks (SAT scores, AC vs. window-opening regions, decades of submarine/spacecraft work) are decisive against Satish-scale effects but close to powerless against small ones. Say true effect were d=0.1: all those comparisons would come back null, and so would most lab studies; hopelessly underpowered. So “we looked hard and found nothing” kills the version that caused the panic but leaves the subtle version about where prior plausibility put it. I don’t think it’s likely either to even have that lower-but-not-entirely-negligible effect, and the practical upshot is identical, because the honest case for ventilation is comfort, bioeffluents, and sleep rather than IQ points (well, assuming that conventional wisdom remains right) – and whether indoor plants make us happy will also continue to hinge on non-CO2 things anyway.
regardless, I simply updated to that I don’t need to worry about CO2 in most normal settings and I don’t have an opinion on whether it has a negligible effect at something like 2000ppm. Obviously at some point CO2 will have an effect on cognition just because an extremely high CO2 level (~40000ppm) is lethal.
I recently saw this on Hacker News (https://news.ycombinator.com/item?id=48787625) and I find it pretty convincing. When I ask AI, they are also skeptical about both the effect of CO2 and the quality of the paper you linked. Both ChatGPT and Claude thinks it is overselling the findings.
Interesting, thanks. (There were too many unhinged comments on Hacker News for this post, so I stopped reading them.
At absolute minimum, I think you show that I was incorrect to claim it’s an established fact that CO₂ is harmful for cognition. And anyway, I don’t need that claim, so I’ve changed it to “sometimes claimed to be”.
Still, it’s interesting to debate if cognitive effects exist. I think the paper at the end (done by the Navy) gives very convincing evidence that the huge effects reported by Satish are not real. If you take Table II, the cognitive test results at 15,000 ppm are indeed worse than at 600 ppm results for 6⁄9 tests. But they’re equal for 2⁄9 tests, and actually better for 1⁄9, and the magnitude where they’re better is the largest of all. They find effect sizes between 0.001 and 0.054, which vaguely suggest a small benefit, but none are statistically significant, and they seem to be using a one-sided estimator.
I guess I’d rate my claim as 90% wrong? Some small effect might exist, but there’s no convincing evidence. So thanks again for the correction!
Yeah, Hacker News is really noisy, that’s why I just linked that specific comment. I didn’t actually read the Navy paper (or any paper regarding CO2), so thanks for the additional point.
I don’t know whether cognitive effects exist at reasonable ppms, but it seems like any real effects would be too small to worth caring for optimizing productivity, so I stopped investigating.
Agreed on substance – I started from the same skepticism and remain with it. Caveat just on structure of your argument: the population-level checks (SAT scores, AC vs. window-opening regions, decades of submarine/spacecraft work) are decisive against Satish-scale effects but close to powerless against small ones. Say true effect were d=0.1: all those comparisons would come back null, and so would most lab studies; hopelessly underpowered. So “we looked hard and found nothing” kills the version that caused the panic but leaves the subtle version about where prior plausibility put it. I don’t think it’s likely either to even have that lower-but-not-entirely-negligible effect, and the practical upshot is identical, because the honest case for ventilation is comfort, bioeffluents, and sleep rather than IQ points (well, assuming that conventional wisdom remains right) – and whether indoor plants make us happy will also continue to hinge on non-CO2 things anyway.
...did you use an LLM to write this comment.
regardless, I simply updated to that I don’t need to worry about CO2 in most normal settings and I don’t have an opinion on whether it has a negligible effect at something like 2000ppm. Obviously at some point CO2 will have an effect on cognition just because an extremely high CO2 level (~40000ppm) is lethal.