But there is a testable claim here [...] The possible gains seem to me to outweigh the costs of the training and the low prior probability of the claim.
Most quack/traditional remedies are testable. Indiscriminately testing them in hopes of finding ones that work is potentially fruitful, but given the current level of scientific knowledge it's probably orders of magnitude more marginally useful to focus on testing the hypotheses located based on biological/medical expertise.
I'm deeply skeptical of the claims made.
They make two claims that are close to central: 1) Breathing while in the middle of reading a sentence makes it more difficult to comprehend. 2) Increasing oxygen to the brain will increase intelligence.
I'm extremely skeptical of both of these claims. The first one is just very strange since they seem to assume that breathing requires "attention." For me, and for most humans, breathing is so reflexive that it takes effort to actively think about it. Moreover, if it did take conscious attention, I'd be very curious to hear an explanation for how we can breathe in our sleep.
The second claim is marginally more plausible, in that it is pretty clear that a lack of oxygen can create problems. But that doesn't mean that more oxygen makes things better. There's a fair bit of literature on human behavior in high oxygen environments. I'm not an expert on this at all, but I've never seen any claim that cognitive functions improved when one switched to high oxygen environments. It is marginally more plausible that increasing glucose access to the brain could actually help, and it is marginally plausible that their suggestions would increase the glucose level which would possibly help. But, even this doesn't fit with very basic empirical data. While it is true that low glucose levels impair cognition, there are a variety of disorders that increase blood glucose levels (such as some forms of diabetes) and I'm not aware of any evidence that slightly elevated glucose levels help, and highly elevated levels lead to comas, long-term brain damage, and lots of other unfun stuff.
The only piece of data I can't think of that possibly supports this is that I seem to recall seeing some evidence that coastal populations generally have higher IQ on average than non-coastal populations (although a quick Google search doesn't turn up anything supporting that claim). But even if this is the case there are a lot of possible explanations for this, including more complicated environments, easier access to certain trace nutrients (such as iodine), as well as better economic situations.
I strongly agree with the skepticism about breathing having any serious effect on attention.
I have a caved-in chest (about medium), have quite poor fitness and can't swim. My lung capacity is way below average, but I have no problems at all concentrating. My attention span is significantly above average, I don't find reading or writing long sentences difficult at all. I can easily hold large chunks of information in my head if I must. My meditation practice is doing just fine. Concentrating for an hour or more is not tricky at all. (I blame video games. Playing >8 hours/day of high-attention games during high-school does this to you.) Only distractions are tricky, but then only if I'm trying to avoid unease.
Last summer, I did about 2 months of jogging to improve my fitness. I went from not being able to run for 10 seconds to running over 20 minutes without pause. This did not affect my mental capacities in any way I could notice. (Memory might have improved, though.) At best, thinking while running improved, but I never found it hard to listen to audiobooks, even when completely out of breath or exhausted.
In my attempts to formulate a response to this post, I find myself obtrusively distracted by paying attention to my own breathing. I am tempted to upvote simply for the use of the word "wackaloonery."
I think Subsumed has the right idea; the potential gains have to be weighed, not just against the effort of conducting the training, but the fact that it might have a negative effect.
To throw some anecdotes at the issue, I have known a number of people with exceptional breath-holding skills, all of whom are notably stupid. There may be some causation running in the other direction, since if they were smarter, they probably would not have bothered practicing so much to hold their breath.
Not because this brief is so breath-taking (well, maybe), but because your breath paces and punctuates your attention and awareness. Whenever you start to give attention to any awareness of stimulus, you hold your breath! When you breathe again, that is part of a pattern where you are releasing your attention from the one focus of awareness and moving it on to wherever it will alight next.
The claim isn't that conscious control of breathing affects attention (though that might be true), it's that spontaneous changes in breathing shape attention.
Someone without much lung capacity might still have good attention for reading and other low-aerobic effort activities if their metabolism is ramped down enough so that they can get what they're thinking about into their memory.
It wouldn't surprise me if there's a connection between breath and attention, but I suspect it's more complex. I might be able to introspect efficiently enough to find out what triggers spacing out, and it would be worth learning.
Reading the part about breathing reducing attention during reading caused me to pay attention to my breathing while reading which reduced my attention, suggesting that breathing during reading reduces attention. Very clever, Mr. Wenger! As JoshuaZ points out, breathing seems unnoticed when one isn't actively thinking about it.
One also has to take into account the probability that this training has negative consequences, which, knowing the effects of hypoxia on neurons, is not negligible.
Mild to moderate anoxia doesn't have long-term effects, and brain neuron apoptosis doesn't start until after about five minutes of anoxia, or so I'm informed by the always-reliable Wikipedia. Other than that, I thnk wedrifid and Vladimir Nesov nailed it.
I have (independently) made similar observations with respect to my personal experience years ago. That said, I certainly wouldn't have gone as far as to present it as a general cognitive enhancement solution. It sounds like the sort of thing that depends on exactly what your cognitive bottlenecks are.
I read this when PJ Eby sent it round. Acecdatum: I have absolutely no idea what the author was talking about. I definitely wasn't holding my breath when he claimed that I would be, and have since noticed that my breathing patterns definitely don't follow those mentioned in the article.
I do quite a lot of underwater swimming, so have pretty good lung capacity (can comfortably(ish) hold my breath for approximately two minutes) no idea if this is relevant.
On January 4, PJ Eby sent around an email linking an... interesting... website. The claim on the particular webpage he linked was as follows:
This site is part of a sales pitch, so many of the claims are stated in hyperbolic language. I've already noted one factual error: the webpage claims that being underwater triggers the diving reflex, while in fact (or at least, according to Wikipedia) the diving reflex is triggered when one's face is immersed in water colder that 21 °C.
But there is a testable claim here: learn to hold your breath for longer periods of time -- particularly in conditions that elicit the diving reflex -- and you will see increased intelligence. I know that some readers of LW regularly train and test their intelligence, so I offer this as an easily implemented potential method. The possible gains seem to me to outweigh the costs of the training and the low prior probability of the claim.