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paulfchristiano comments on What is up with carbon dioxide and cognition? An offer - Less Wrong
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It is odd, isn't it? The effect sizes seem ridiculous*, but there's nothing obviously wrong with that study (aside from the sample size). Cochran has blogged about oxygen before as well. To compile some of the relevant papers:
The problem for me is that while it makes sense that since we run on oxygen and the brain uses a lot of oxygen (the whole 'BOLD' thing etc), more oxygen might be better, it has the same issue as Kurzban's blood-glucose/willpower criticism: if the brain needs more oxygen than it's getting, why doesn't one simply breath a little more? While sedentary during these sorts of tasks, you have far more breathing capacity than you should need - you are able to sprint all-out without falling over of asphyxiation, after all. So there's no obvious reason there should be any lack, even more so than for glucose. And shouldn't CO2 levels closely track various aspects of weather? But as far as I know, various attempts to correlate weather and cognitive performance or mood have turned up only tiny effects. In addition, too much oxygen can be bad. So is it too little oxygen or too much nitrogen or too much carbon dioxide...?
What monitor is that? You could try recording CO2 long-term, especially if it's a data logger. Opening windows is something that's easily randomized.
I did some looking and compiling of consumer-oriented devices a while ago: https://forum.quantifiedself.com/t/indoor-air-quality-monitoring-health/799/40 I was not too impressed since nothing hit the sweet spot of accurate CO2 and PPM measurement under $100. The Netatmo looked decent but there are a lot of complaints about accuracy & reliability (checking the most recent Amazon reviews, still a lot of complaints).
I've been thinking maybe I should settle for the Netatmo. I've been working on a structural equation model (SEM) integrating ~100 personal data variables to try to model my productivity (some current sample output), and it would be nice to have even noisy daily C02 variables (as long as I know how noisy and can use it as a latent variable to deal with the measurement error). Correlation-wise, I think backwards causation can be mostly ruled out, and the most obvious confound is weather, which is already in my SEM.
* taken at face value, with reasonable estimates of how much rooms differ from day to day or week to week, CO2 levels would explain a lot or maybe most of variability in IQ tests or cognitive performance!
I don't see how it can be about oxygen. In the paper I linked, I think they directly add relatively pure carbon dioxide. And the total concentration is 0.1%. So the concentration of oxygen in the air is not really changing.
The texas natural experiment seems like an especially convincing complement to the more artificial setting, thanks for pointing it out.
If you look into this I will leave open the offer to buy certificates after the prize. So far not many takers on the prize, this comment is currently in the lead based on the literature review, not sure if there will be takers closer to the cutoff.
The sample size is small, but given the effect size I don't think it even matters that much. The error seems like less than a factor of 2.
This looks right to me (well "a lot," I don't think "most"), I assume that something is wrong. An obvious possible culprit is their cognitive test.
Can't you apply that argument to oxygen and nitrogen as well? If you are willing to believe that adding a small absolute amount of carbon dioxide can have large effects on the brain, then I don't see why you would not also be willing to believe that decreasing oxygen (a critical fuel for the brain's metabolism) by a small absolute amount might have large effects on the brain. Injecting CO2 as they do does control for air variables like mold and temperature and humidity, but I didn't see anything about also injecting oxygen and nitrogen to independently manipulate the air composition in all 9 possible ways to disentangle which it is. It could be that CO2 is inert, but by pushing out oxygen and reducing oxygen levels has effects; it could be that CO2 is inert but it's both oxygen and nitrogen, or CO2 is poisonous but is combining with lack of oxygen.
I found it interesting that the anti-mold renovations had such large apparent effects compared to the ventilation and other renovations.
Small study effects go beyond just sampling error, so they are untrustworthy.
The CO2 intervention is doubling the density of CO2, and decreasing the density of oxygen by < 1%.
Small proportional changes seem unlikely to drive big effects, unless there is some feedback mechanism that is keeping the level precisely balanced. But 1% changes in oxygen should be happening all over the place. It seems much more plausible for doubling the density of CO2 to have a direct effect.
Similarly, the nitrogen intervention is a significant proportional change.
Such as in the body, dealing with tightly regulated and critical aspects of metabolism like oxygen consumption.
Perhaps they are. You don't know the effect because the existing experiments do not vary or hold constant oxygen levels. All you see is the net average effect, without any sort of partitioning among causes.
Existing experiments do vary oxygen levels systematically, albeit usually unintentionally, by geography. Going up 100 meters from sea level gives you a 1% drop in oxygen pressure and density. If that was enough for a detectable effect on IQ, then even the 16% lower oxygen levels around Denver should leave Coloradans obviously handicapped. IIRC altitude sickness does show a strong effect on mental performance, but only at significantly lower air pressures still.
And they also vary CO2 levels systematically by geography as well; if that was enough for a detectable effect on IQ, then the lower CO2 levels around Denver should make the rest of us at lower altitudes, such as sea level, look obviously handicapped. If you believe the altitude point refutes effects of oxygen, then it must refute effects of carbon dioxide and nitrogen as well...
Which is part of my original point about implausible effect sizes: the causal effect is underidentified, but whether it's oxygen or CO2 or nitrogen, it is so large that we should be able to see its repercussions all over in things like the weather (or altitude, yes).
The magnitude of the variation isn't nearly the same in the O2 vs CO2 cases. "16% O2 reduction is lost in the noise" is devastating evidence against the theory "0.2% O2 reduction has significant cognitive effects", but "16% CO2 reduction is lost in the noise" is weaker evidence against the theory "66% and 300% CO2 increases have significant cognitive effects".
I'm not arguing with you about implausible effect sizes, though. We should especially see significant seasonal effects in every climate where people typically seal up buildings against the cold or the heat for months at a time.
It seems possible (I know of no evidence for or against) that human bodies adapt slowly to differences in O2 and CO2 level. In that case, newcomers to Denver might be smarter or stupider for a while, but after (say) a few months they might be back to baseline, but short-term fluctuations (e.g., sitting for a few hours in an office with slightly depleted O2 and slightly raised O2) could still have detectable cognitive effects.
I meant, changing a level by 1% probably won't have a huge effect (e.g. 1/2 of a standard deviation) unless that level is itself controlled by a homeostatic process (or else has almost no variation).