
Higher Levels of CO2 May Diminish Decision Making Performance (2013) [pdf] - bryanrasmussen
https://eetd.lbl.gov/sites/all/files/lbnl-6148e-is_co2_an_indoor_pollutant_v3.pdf
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gwern
Some earlier discussion:
[http://lesswrong.com/r/discussion/lw/nk0/what_is_up_with_car...](http://lesswrong.com/r/discussion/lw/nk0/what_is_up_with_carbon_dioxide_and_cognition_an/)
It's hard to see how these results could be possible, especially considering
the broad null results from the many Navy experiments with thousands of PPMs.

~~~
dmlorenzetti
What do you find impossible about the results?

While the blog post you linked to claims that the work finds "implausibly
large effects", it doesn't clarify what the author finds implausible about
them (and the author admits to only spending 30 minutes looking at the
literature).

I would agree that the graphic in the PDF linked in this HN discussion, and in
the paper referenced by the blog post you cited, uses alarmist labels (e.g.,
"dysfunctional" for performance scores at 25th percentile and below). However,
the full version of the report, as linked by post, states that the percentiles
are based on the reported scores from 20k other administrations of the test.

Therefore this report simply implies that some of the reported variation in
some of the historical scores might be explained by variations in room CO2
concentrations. What's so implausible/impossible about that?

Disclaimer: I know several of the authors of this report, and have good regard
for their scientific integrity, so my gut-level reaction to an undocumented
accusation that their results are implausible, was skeptical.

~~~
CamperBob2
_What do you find impossible about the results?_

The whole idea behind "breathing" is to regulate the CO2 in the blood at a
very constant level. This is one of the strongest, fastest feedback loops in
homeostasis. How are relatively small changes in environmental CO2 making
their way into the bloodstream? Did they actually conduct blood tests to see
if the test conditions were reflected in the subjects' physiology?

~~~
Terr_
> The whole idea behind "breathing" is to regulate the CO2 in the blood

True, but two devil's-advocate what-ifs come to mind.

First, the system isn't so responsive to a lack of oxygen, and in many of the
"low ventilation with people" scenarios, higher CO2 correlates with lower O2,
because that's the conversion going on.

Second, might the body down-regulate mental resources as a response to
chronically higher CO2 in the environment? As an adaptive or precautionary
measure, helping keep that blood-concentration correct?

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Robotbeat
This will, of course, start to bite immediately on the margin.

If you have a poorly ventilated building, you're already at a disadvantage now
with >400ppm outside air (higher in cities) than you would've been, say, 200
years ago with 280ppm air.

CO2 is absolutely a pollutant. Yes, plants like it, but we are not plants. It
is a waste product, and too much of it affects mental performance.

~~~
epmaybe
our bodies are pretty darn good at reducing CO2 in our blood. CO2 isn't the
problem for our bodies, by far.

~~~
ams6110
Indeed. 400 ppm of CO2 compared to 300 is likely negligible for human
respiration, compared to the 201,000 ppm O2 and 780,000 ppm N2 in the
atmosphere.

0.04% vs 20% and 78%

~~~
metaobject
Well, N2 molecules have very strong bonds that aren't easily broken so they
ddon't tend to react with much of anything inside our bodies.

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elihu
Their test cases were 600 ppm, 1000 ppm, and 2500 ppm of CO2, and they found
measurable differences in human performance between those.

I am curious what would happen if they dropped the CO2 concentration down to
something that's less than what they see in an urban environment? Does
dropping to 300 ppm or 0 ppm have any measurable benefit? Are there any
downsides to breathing air with no CO2?

~~~
parhurs
Well, too little carbon dioxide in the bloodstream changes the blood's pH,
which is a negative. Can't tell how ambient CO2 levels affect it though.

~~~
Nanite
This would be hyperventilation syndrome

[https://en.wikipedia.org/wiki/Hyperventilation_syndrome](https://en.wikipedia.org/wiki/Hyperventilation_syndrome)

CO2 is not simply a waste product we exhale, we need it for pH regulation of
our blood.

------
kafkaesq
"But we don't need you to 'decide' anything, in this job. We just need you to
put your your weekly quota of TPS reports. So stop complaining about the open
office plan the ventilation, and just as importantly, stop confusing everyone
with all this nonsense science talk. And get back to work!"

~~~
tajen
I'm more concerned about classrooms. In France it's perfectly accepted to keep
pupils for 4hrs in a closed classroom (except the break), especially if it's
winter, because heaters are half-closed for savings. Now when I lived in
Australia, vents are adequate for the size of the room, I wouldn't be
surprised if it has a huge effect on population education.

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rbanffy
So, the worse CO2 levels get, the more climate change deniers we'll have...
;-)

Even if TFA seems odd, if the population is large enough, even a marginal
change in performance will have measurable total effects.

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burntrelish1273
In a VC pitch, sneak in a briefcase that slowly dispenses CO2 while the
founders clip their toenails.

<jedi-mind-trick> _This is one of the startups you 're going to invest in this
cycle._ </jedi-mind-trick> :)

