Skeptophilia (skep-to-fil-i-a) (n.) - the love of logical thought, skepticism, and thinking critically. Being an exploration of the applications of skeptical thinking to the world at large, with periodic excursions into linguistics, music, politics, cryptozoology, and why people keep seeing the face of Jesus on grilled cheese sandwiches.
Showing posts with label signal-to-noise ratio. Show all posts
Showing posts with label signal-to-noise ratio. Show all posts

Monday, September 8, 2025

Wheat from chaff

My question today is one that haunts many skeptics -- how would you know if a bizarre claim is actually true, especially in the absence of evidence?

The hardest-nosed of us would probably object to the premises of the question; if there is no evidence, they would say, then there is no basis on which to make a judgment in the first place.  While I agree with that general attitude -- and have applied it myself on numerous occasions -- it always leaves me with the worry that I'll miss something, and just through the weakness of the evidence and my preconceived notions, I won't see the grain of wheat in amongst the chaff.

I riffed on this whole idea in my novel Signal to Noise (and if you'll allow me a moment of shameless self-promotion, it is available at Amazon from the link on the right side of the page).  In the story, a skeptical wildlife biologist, who had decided that all woo-woo claims are utter bullshit, is confronted with something bizarre going on in the mountains of central Oregon -- and has to overcome his preconceived biases even to admit that it might be real.  In the story, it doesn't help that the news is delivered to him with no hard evidence whatsoever, by a total stranger who just "has a feeling that something is wrong."  (I won't tell you any more about it; you'll just have to read it yourself.  And at the risk of appearing immodest, I think it's a pretty damn good story.)

The reason I bring all of this up is a website called Little Sticky Legs: Alien Abductee Portraits, owned by Steven Hirsch.  On this website, which you should definitely take a look at, there are photographs of a number of people who claim that they were abducted by, or at least contacted by, aliens, and their first-hand accounts (and in some cases drawings) of their experiences.  I thought this was an unusually good example of the phenomenon I've described above, for a variety of reasons.

First, the accounts are weird, rambling, and disjointed, and many of them seem to have only a loose attachment to reality.  Second, the photos don't help; whether Hirsch deliberately set out to make his subjects look sketchy is a matter of conjecture, but my sense is that he was playing fair and this is the way these people actually look.  Some of them, not to put too fine a point on it, are a little scary.  And third, of course, the content of the accounts is fairly contrary to what most scientists think is realistic.  All of these things combined seem to put their stories squarely into the category of bizarre, possibly delusional, nonsense.


But reading the earnest narratives of these supposed contactees left me feeling a little uneasy.  Part of it was a sense that if their stories aren't true, then these people are either lying or else are the victims of hallucinations that could qualify as psychotic breaks.  And although I am rather free about poking fun at folks who generate strange ideas, I draw the line at including as targets people who have genuine mental illnesses.

My unease, however, had another source, and one that haunts me every time I see something like this; what if one of these stories is actually true?

A person who had been abducted, but was left with no physical trace of the experience, might well describe it in just these terms.  If the victim was someone who wasn't highly educated, there's no reason to expect that (s)he would remember the details, or explain them afterwards, in the way a trained scientist would.  The general vagueness and lack of clarity is, in fact, exactly what you'd expect if an ordinary person experienced something shockingly outside their worldview.

Now, please don't misunderstand me.  I'm not, in any sense, committing to a belief in alien abductions in general, much less to any specific one of the stories on Hirsch's website.  My hunch is that none of these stories is true, and that whatever these individuals are describing has another source than actual experience.  But it is only a hunch, and an honest skeptic would have to admit that there is no more evidence that these claims are false than there is that they are true.  My only point here is that if one of them was telling the truth, this is much the form I would expect it to take... which means that it behooves all of us, and especially the skeptics, not to discount odd claims without further inquiry.  Skeptics tend to rail against the superstitious for jumping to supernatural explanations for completely natural phenomena; we should be equally careful not to jump to prosaic explanations when an odd one might be correct.

Carl Sagan famously said, "Extraordinary claims require extraordinary evidence."  Which is an excellent rule of thumb, with one addition.  Accepting an extraordinary claim requires extraordinary evidence.  Investigating an extraordinary claim requires only that you keep your mind open -- and see if there's anything there which might allow you to make a rational evaluation of its truth or falsity.

The best thing, of course, is to withhold judgment completely until the facts are in, but that is pretty solidly counter to human nature, and is probably unrealistic as a general approach.  And given the ephemeral nature of some of these claims, the facts may never come in at all.  All we can do is keep thinking, keep watching and listening and investigating... and not be afraid to push the envelope of our own understanding when the time comes.

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Tuesday, November 20, 2018

Wheat, chaff, and alien abductions

My question today is one that haunts many skeptics -- the question of how one would know if a bizarre claim was actually true, especially in the absence of evidence.

The hardest-nosed of us would probably object to the premises of the question; if there is no evidence, they would say, then there is no basis on which to make a judgment in the first place.  While I agree with that general attitude -- and have applied it myself on numerous occasions -- it always leaves me with the worry that I'll miss something, and just through the weakness of the evidence and my preconceived notions I won't see the grain of wheat in amongst the chaff.

I riffed on this whole idea in my novel Signal to Noise (and if you'll allow me a moment of shameless self-promotion, it is available at Amazon from the link on the right side of the page).  In the story, a skeptical wildlife biologist, who had decided that all woo-woo claims are bullshit, is confronted with something bizarre going on in the mountains of central Oregon -- and has to overcome his preconceived notions even to admit that it might be real.  In the story, it doesn't help that the news is delivered to him with no hard evidence whatsoever, by a total stranger who just "has a feeling that something is wrong."  (I won't tell you any more about it; you'll just have to read it yourself.   And at the risk of appearing immodest, I think it's a pretty damn good story.)

The reason I bring all of this up is a website called Little Sticky Legs: Alien Abductee Portraits, owned by Steven Hirsch.  On this website, which you should definitely take a look at, there are photographs of a number of people who claim that they were abducted by, or at least contacted by, aliens, and their first-hand accounts (and in some cases drawings) of their experiences.  I thought this was an unusually good example of the phenomenon I've described above, for a variety of reasons.

First, the accounts are weird, rambling, and disjointed, and many of them seem to have only a loose attachment to reality.  Second, the photos don't help; whether Hirsch deliberately set out to make his subjects look sketchy is a matter of conjecture, but my sense is that he was playing fair and this is the way these people actually look.  Some of them, not to put too fine a point on it, are a little scary.  And third, of course, the content of the accounts is fairly contrary to what most scientists think is realistic.  All of these things combined seem to put them squarely into the category of most of the subjects of this blog; bizarre, possibly delusional, nonsense.


But reading the earnest narratives of these supposed contactees left me feeling a little uneasy.  Part of it was a sense that if their stories aren't true, then these people are either lying or else are the victims of hallucinations that could qualify as psychotic breaks.  And although I am rather free about poking fun at people who generate strange ideas, I draw the line at including as targets people who have genuine mental illnesses.

My unease, however, had another source, and one that haunts me every time I see something like this; what if one of these stories is actually true?

A person who had been abducted, but was left with no physical trace of the experience, might well describe it in just these terms.  If the victim was someone who wasn't highly educated, there's no reason to expect that (s)he would remember the details, or explain them afterwards, in the way a trained scientist would.  The general vagueness and lack of clarity is, in fact, exactly what you'd expect if an ordinary person experienced something shockingly outside their worldview.

Now, please don't misunderstand me.  I'm not, in any sense, committing to a belief in alien abductions in general, much less to any specific one of the stories on Hirsch's website.  My hunch is that none of these stories is true, and that whatever these individuals is describing has another source than actual experience.  But it is only a hunch, and an honest skeptic would have to admit that there is no more evidence that these claims are false than there is that they are true.  My only point here is that if one of them was telling the truth, this is much the form I would expect it to take... which means that it behooves all of us, and especially the skeptics, not to discount odd claims without further investigation.  Skeptics tend to rail against the superstitious for jumping to supernatural explanations for completely natural phenomena; we should be equally careful not to jump to prosaic explanations when an odd one might be correct.

The best thing, of course, is to withhold judgment completely until the facts are in, but that is pretty solidly counter to human nature, and is probably unrealistic as a general approach.  And given the ephemeral nature of some of these claims, the facts may never come in at all.  All we can do is keep thinking, keep watching and listening and investigating... and not be afraid to push the envelope of our own understanding when the time comes.

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This week's Skeptophilia book recommendation is a fun one -- Mary Roach's Spook.  Roach is combines humor with serious scientific investigation, and has looked into such subjects as sex (Bonk), death (Stiff), war (Grunt), and food (Gulp).  (She's also fond of hilarious one-word titles.)

In Spook, Roach looks at claims of the afterlife, and her investigation takes her from a reincarnation research facility in India to a University of Virginia study on near-death experiences to a British school for mediums.  Along the way she considers the evidence for and against -- and her ponderings make for absolutely delightful reading.




Monday, March 9, 2015

The source of the noise

A common theme in Skeptophilia is that people in general need to learn some scientific terminology.

Not only is science cool, and thus learning about it a worthy goal in and of itself; but knowing how science works, and some of the field's vocabulary, will keep you from being duped.  As we've seen over and over, the world is full of folks who either through ignorance or outright duplicity misrepresent what scientists are doing -- and without adequate mental firepower, you're gonna fall for their nonsense every time.

As an example, this weekend, a story started popping up all over that claimed that we'd finally received a good candidate for an alien signal from an extrasolar planet.  This immediately caught my eye -- it is one of my dearest wishes that we have incontrovertible evidence of alien intelligence before I die.  I'd be perfectly satisfied if it comes in the form of some kind of radio signal, but if an actual alien spacecraft landed in my back yard, that would also be acceptable, at least until they started vaporizing my dogs with laser pistols.

So my reaction was one of cautious enthusiasm.  Cautious, because I suspected that if this had actually happened, it would be all over the news, not just surfacing in the form of links on Twitter and Facebook.  But the stories all made the same claim.  Here's an excerpt from the version that appeared on UFO Blogger:
Astronomers have picked up a mystery "noise" which they believe could be coming from an Earth-like planet in the outer space [sic]. After analyzing the strange signals emitting from the object, scientiscientistssts [sic] are certain that a habitable planet exists some 22 light years away, a report said. 
In 2010, scientists had dismissed the mystery noise or signals as stellar bursts but after the latest research it was clear that an Earth-like planet, or Gliese 581d, has conditions which could support life, and is likely to be a rocky world, twice the size of Earth.
Okay, given the typos and grammar, it's not exactly the most credible of reports.  But all of the links I saw agreed; an extrasolar planet called Gliese 581d, 22 light years from Earth, had been reported as the source of a strange, unexplained noise.  The planet was bigger than Earth, but in the "Goldilocks Zone" -- the "just right" region around its star where water would be in liquid form, and therefore a place where life something like what we have here could evolve.

So immediately I started picturing Star Trek-style aliens, complete with fake rubber alien noses and bad accents.  Then I thought of the amazing final scene in Star Trek: First Contact, which is clearly the best movie the franchise ever produced, wherein Zefram Cochrane shakes hands with a Vulcan for the first time.  And before you know it, I had myself worked up into a lather about the possibilities.


Then I thought, "Calm down, dude.  Verify your sources."  So I typed "noise Gliese 581d" into a Google search to see if I could find out where this information had come from.  Clearly it was all similar enough that it had some kind of common origin, and it wasn't wacky enough to have come from The Weekly World News.  And after five minutes' search, I found the press release in Phys.org that had caused the stir -- the origin of the "noise."

And I put "noise" in quotation marks for a good reason, as you'll see.  The press release was a blurb summarizing a paper in Science by Anglada-Escudé and Tuomi called "Stellar activity masquerading as planets in the habitable zone of the M dwarf Gliese 581."  Here's the relevant passage:
A report published in Science has dismissed claims made last year that the first super-Earth planet discovered in the habitable zone of a distant star was 'stellar activity masquerading as planets.' The researchers are confident the planet named GJ 581d, identified in 2009 orbiting the star Gliese 581, does exist, and that last year's claim was triggered by inadequate analysis of the data.

The planet candidate was spotted using a spectrometer which measures the 'wobble', small changes in the wavelength of light emitted by a star, caused as a planet orbits it. In 2014 researchers revisiting the data said that the 'planet' was actually just noise in the data caused by starspots. The possible existence of the planet was widely dismissed without further questioning. 
But now researchers from Queen Mary University of London (QMUL) and University of Hertfordshire have questioned the methods used to challenge the planet's existence. The statistical technique used in the 2014 research to account for stellar activity is simply inadequate for identifying small planets like GJ 581d.
Note the use of the word "noise" twice.  This, apparently, is the source of the story of an alien noise coming from Gliese 581d.

Scientists use the word "noise" differently from the rest of us.  To a scientist, "noise" is scatter in the data, background junk, that might obscure something real and measurable (the "signal").  If you have enough noise, the signal becomes impossible to detect, so reducing the noise in a data set is critical.  A high "signal-to-noise ratio" is what you're after; lots of signal, little noise.  So when the astrophysicists re-analyzed the data from 2009 that had been rejected last year as supporting an Earth-like extrasolar planet around Gliese 581, they found a way of reducing the noise in the data, and were able to confirm that the planet did, actually, exist.

What they did not find was some kind of unexplained noise coming from Gliese 581d.  The noise was the scatter in the data, not some Klingon sending an insulting message at the Earth such as "Hab SoSlI' Quch" ("Your mother has a smooth forehead").

Not that I'm happy to report this, mind you.  No one would be more thrilled than me if we had received an alien communiqué, even if it contained an insult.  But unfortunately, the stories about mysterious and unexplained alien noises turn out to be unmysterious and completely explainable ignorance of bloggers regarding the use of scientific vocabulary.

So we keep waiting.  Given the number of extrasolar planets the astronomers are discovering, I'm still optimistic that one day, we'll find the aliens.  Or maybe they'll find us.  Either way, it'd be amazing, because, after all, Heghlu'meH QaQ jajvam ("Today is a good day to die").