Near Death Experiences Explained... Debunked

[fls]

Have you checked that you are both running either a one-tailed test or a two-tailed t-test? If they used a one-tailed t-test and your calculator gives the result for a two-tailed t-test, that might account for the discrepancy.

Are you confusing paired samples with unpaired samples? A one-tailed t-test will return a p-value which is half that of the two-tailed test.

Linda

 

[Beth]

Are you confusing paired samples with unpaired samples? A one-tailed t-test will return a p-value which is half that of the two-tailed test.

Linda

Ach! You're right. That wouldn't be it.

 

[Maia]

Ach! You're right. That wouldn't be it.

There must be some reason why they ended up with such different numbers, but I really and honestly can't come up with what it is. I have contributed work to studies and run numbers before (no guarantees as to how good any of this was.) It's just bugging me that I can't see how they came up with these numbers. In any case, as others have pointed out, the much bigger problem is that it was such a very small sample that there was no way to get anything truly accurate out of the number of subjects they had. Mostly, though, they ended up with the subjects who seemed to be the healthiest to begin with (the younger ones whose hearts seemed to be in better shape.) The main conclusion I drew from the entire thing was that out of 426 resuscitation attempts, they had 76 survivors. Somehow, I always thought the odds would be better than THAT...

 

[GrandMasterFox]

Sorry for a very stupid question and possibly derailing the topic a bit, but wasn't NDE debunked ages ago?

I recall something vague about an old Penn and Teller show where they talked about how NDEs could be recreated with the NASA centrefuge or something like that.

 

[Almo]

Sorry for a very stupid question and possibly derailing the topic a bit, but wasn't NDE debunked ages ago?

I recall something vague about an old Penn and Teller show where they talked about how NDEs could be recreated with the NASA centrefuge or something like that.

Not a stupid question, but it has an answer that some people don't like.

 

[dlorde]

Sorry for a very stupid question and possibly derailing the topic a bit, but wasn't NDE debunked ages ago?

I recall something vague about an old Penn and Teller show where they talked about how NDEs could be recreated with the NASA centrefuge or something like that.

Yup, fighter pilots can get NDEs during hi-G training in centrifuges - they're associated with brown-outs & black-outs due to oxygen starvation in the brain.

 

[Baby Nemesis]

... But I can’t stand what the popular press does to scientific research,
and to be perfectly honest, I was not impressed by this research anyway. Here’s why. Please read all the way to the end before commenting. I did a lot of original work on this, ALL BY MYSELF. ...

This is a significant error because only petCo2 levels were indeed significantly higher in the study, not pCo2 levels. I do appreciate what fls says about that p value issue.... but the way this was reported in the media was so inaccurate, and if they're going to even try to explain these things and then they get that part so wrong, too...

Anyway, the media will find something else to jump on next week and will be just as inaccurate about it.

I've just had a quick look for information about near death experiences in Google, and have come across what I presume to be the original National Geographic article you're so indignant about. It turns out that this is not a case of misreporting or hype in the popular press at all. It's a cautious article, and the claim of the "significance" of blood carbon dioxide levels is a direct quote from one of the study authors, not a media misinterpretation of the study results.

I will quote a bit from the article to illustrate, with a couple of the relevant bits highlighted. This quote will also illustrate that this was not, as you appear to imagine for some reason, an article that merely promoted the study. It takes an objective look, quoting one or two people who are rather skeptical of it. It leaves me wondering why you're so outraged by the article:

Near-death experiences are tricks of the mind triggered by an overload of carbon dioxide in the bloodstream, a new study suggests. ...

"We found that in those patients who experienced the phenomenon, blood carbon-dioxide levels were significantly higher than in those who did not," said team member Zalika Klemenc-Ketis, of the University of Maribor in Slovenia. ...

The hospital study bolsters previous lab work done in the 1950s that found "the effects of hypercarbia [abnormally high levels of CO2 in the blood] were very similar to what we would now recognise as NDEs," French said in an email.

The research also supports the argument that anything that disinhibits the brain—damages the brain's ability to manage impulses—can produce near-death sensations, he said. Physical brain injury, drugs, and delirium have all been associated with a disinhibited state, and CO2 overload is another potential trigger.

Still, not all scientists are convinced: "The one difficulty in arguing that CO2 is the cause is that in cardiac arrests, everybody has high CO2 but only 10 percent have NDEs," said neuropsychiatrist Peter Fenwick of the Institute of Psychiatry at Kings College London.

The very heading of the article had a question mark at the end, indicating right from the very beginning that the study findings were being treated with caution. How can you have failed to pick up on this? "Near-Death Experiences Explained?"

Also, it's almost immediately evident from the article that the sample size was tiny.

It's only a short article, so your failure to pick those things up does give an impression of a rather over-hasty approach on your part, one that wasted a fair bit of your time, since it was totally unnecessary to go to the original study and do some in-depth calculations to discern the fact that this study had very little significance indeed.

You've been debunking a red herring, one of your own making.

 

[Iconoclast08]

No, alpha = .05 is a common and correct arbitrarylevel to use...

There, fixed it.