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Anomaly Hunting

by Steven Novella, Apr 27 2009

There are numerous ways in which thought processes go astray, leading us to false conclusions, even persistent delusions. Skepticism, as an intellectual endeavor, is the study of these mental pitfalls, for a thorough understanding of them is the best way to avoid them.

Science itself is a set of methods for avoiding or minimizing errors in observation, memory, and analysis. Our instincts cannot be trusted, so we need to keep them in check with objective outcome measures, systematic observation, and rigid control of variables. In fact bias has a way of creeping into any observation and exerting powerful if subtle effects, leading to the need to completely blind scientific experiments. Good scientists have learned not to trust even themselves.

One of the most common and insidious bits of cognitive self-deception is the process of anomaly hunting. A true anomaly is something that cannot be explained by our current model of nature – it doesn’t fit into existing theories. Anomalies are therefore very useful to scientific inquiry because they point to new knowledge, the potential to deepen or extend existing theories.

For example, the orbit of Mercury could not be explained by Newtownian mechanics – it was a true anomaly. It and other anomalies hinted at the fact that Newton’s laws of motion were incomplete in a fundamental way. This recognition eventually lead to Einstein’s revolution of relativity theory.

Pseudoscientists – those pretending to do science (maybe even sincerely believing they are doing science) but who get the process profoundly wrong, use anomalies in a different way. They often engage it what we call anomaly hunting – looking for apparent anomalies. They are not, however, looking for clues to a deeper understanding of reality. They are often hunting for anomalies in service to the overarching pseudoscientific process of reverse engineering scientific conclusions.

What this means is that pseudoscience almost always works backwards – that is its primary malfunction, starting with a desired conclusion and then looking for evidence and twisting logic to support that conclusion.

With regard to anomalies the logic often works like this: “If my pet theory is true then when I look at the data I will find anomalies.” The unstated major premise of this logic is that if their pet theory were not true then they would not find anomalies. This is naive, however. Another component of this line of argument is the broad definition of anomaly.

In real science an anomaly is only declared so after exhaustive efforts to explain it within existing theories fail. Astronomers checked and quadruple checked their calculations of Mercury’s orbit. They hypothesized that there were other bodies in the solar system exerting gravitational effects on Mercury. They did everything they could to explain Mercury’s orbit within Newtonian physics.  This process didn’t really end until Einstein explained the orbit of Mercury.

What pseudoscientists do is look for “apparent” anomalies – things that cannot be immediately explained, or (even worse) are just quirky coincidences. Often they also look at the edges of detectability where data becomes fuzzy and anomalies are easier to imagine. Think of the fuzzy pictures of Bigfoot or UFOs, with believers looking at details smaller than the resolution of the images and declaring the presence of anomalies.

They imagine that if they can find (broadly defined) anomalies in that data that would point to another phenomenon at work. They then commit a pair of logical fallacies. First, the confuse unexplained with unexplainable. This leads them to prematurely declare something a true anomaly, without first exhaustively trying to explain it with conventional means. Second they use the argument from ignorance, saying that because we cannot explain an anomaly that means their specific pet theory must be true. I don’t know what that fuzzy obect in the sky is – therefore it is an alien spacecraft.

What pseudoscientists often fail to recognize is that if you take any complex natural phenomenon, historical event, object or process and you look for apparent anomalies (broadly defined), you will find them. Humans are great at pattern recognition, and so if you look for coincidence in the data you will detect them. You will also find features that resulted from a complex interplay if unique events and therefore will be impossible to prove a specific explanation.

The JFK conspiracy theorists are masters of anomaly hunting. The events of that day were confused and panicked, on all sides. It would be amazing if you couldn’t find many unusual features.

Richard Hoagland

But the absolute king of anomaly hunting must be Richard Hoagland. He can turn anything into a conspiracy – and not just any conspiracy, but his specific bizarre belief system in alien civilizations, NASA cover ups, and tetrahedrons.

I was recently pointed to this essay by Hoagland on the Saturnian moon Iapetus. Iapetus is genuinely a cool world, with very unusual geology. We are still in the process of exploring this moon, generating hypotheses as to what processes could have created its unique features, and then testing those hypotheses.

But at this point in our exploration of the solar system and the universe it should be expected that most new things we discover will be new an interesting, not familiar and explained. There is no reason to think that earth geology should explain the features on other planets and moons that are experiencing and resulted from very different forces and processes than those at work on earth. We also have a very limited data set, with close robotic exploration of a few planets and a few dozen moons. We should expect that we are very far from anything approaching a thorough science of exogeology.

For Hoagland this means that NASA images of other bodies in our solar system is a rich source for anomaly hunting – a hobby he engages in with utter enthusiasm. His essay is just chock full of anomaly hunting -he even uses the term often. Most of his anomalies are not really anomalies, they are not terribly interesting coincidence, or just his favorite tactic of using low-res images and an active imagination.

For example, about one low-res image of Iapetus he writes:

Note (close-up, below) the string of bright, reflecting objects — hanging (somehow …) well above the satellite’s limb ….

iapetus-architecture6There are two explanations for these “floating” objects that would need to be excluded before concluding that they are anomalies requiring the introduction of a new element to explain. The first is that it is just pixelization artifact. Again – this is at the limits of resolution, where Hoagland thrives. But perhaps a more likely explanation is that this is just the peaks of mountains catching the sunlight, while the base is in shadow. Isn’t that exactly what we would expect at the rim of the lighted side of a moon?

That is about the level of Hoaglands anomalies. But the central anomaly of this website is the “wall” of Iapetus.

Iapetus is shaped somewhat like a walnut, with a ridge that goes around its equator. Something funky definitely happened to Iapetus to create this ridge, and astronomers are having fun trying to figure out exactly what that was. Hoagland, however, leaps (with some fancy pirouettes, a double twist and a flourish) to the conclusion that the ridge is a manufactured wall. He then uses his “low res” trick to imagine “anomalies” in the ridge, then uses the logical fallacy one-two punch (confusing unexplained with unexplainable and the argument from ignorance) to conclude that aliens not only constructed a wall around Iapetus, they constructed Iapetus.

But Hoagland’s enemy, his arch-nemesis, is the ever increasing resolution with which NASA images the solar system. This was his undoing with the infamous “face on Mars” photo that Hoagland championed. Later higher resolution images showed the face on Mars to be a natural formation. Hoagland recovered, however, by claiming (you guessed it) a NASA conspiracy. iapetus

His essay is built largely on the low-res pictures from the Voyager probes, with some Cassini images. He has not yet updated the site with the higher resolution pictures of Iapetus from Cassini. With these higher resolution images Hoagland’s wall look suspiciously like a natural mountain range – albeit one unfamiliar to earth-bound observers.

Of course these images are coming from NASA so Hoagland should have no difficulty dismissing them.


Pseudoscientists, like Hoagland, abuse the concept of anomalies in many ways. They look for apparent anomalies, then prematurely conclude they are true anomalies, and use them to confirm a conclusion they already had in mind.

They fail to recognize that finding apparent anomalies or coincidences is not predictive that a new phenomenon is actually at work. Life is full of apparent anomalies and coincidence, and we evolved the pattern-recognition software to find them and be compelled by them.  That is the ultimate cognitive pitfall of anomaly hunting, and why we need science and skepticism to ward against such pitfalls.

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25 Responses to “Anomaly Hunting”

  1. Pseudoscientists = Gap Hunters

  2. Max says:

    Mercury’s orbit, a reminder that Occam’s razor works until it doesn’t.

    • Wrong says:

      Occam’s Razor has never been a step in formal logic. It’s a heuristic tool for working out the most Likely explanation. It’s an inductive and short process. To use it to construct a logical arguement would be a logical fallacy, and to imply that Occam’s Razor doesn’t work simply because the simplest explanation doesn’t work is stupid. It’s pointless, it’s wrong, and it shows that you have no understanding of the tool.

      Say I have a slice of pizza on my desk. I go down the noisy stairs to get a drink. When I get back, it is gone. I have two options: My youngest brother who was upstairs ate it, or my brother downstairs got upstairs without making a sound and ate it, and snuck down (Barring some explanation involving say, aliens, but they can be excluded by Occam’s Razor as Unlikely).
      I look at the two options: My brother sneaking up the stairs is unlikely, and it assumes he is capable of doing so, and did so.
      While no such assumption requires that the younger brother ate it. Therefore, it is most likely the younger brother who ate it. If I go to him, and find out that my other brother did sneak up the stairs, then suddenly my assumption was proved correct, and both explanations are equally valid.

      Occam’s Razor simply excludes unwarranted assumptions: If those assumptions are correct, then an Unlikely solution becomes the correct one. It is logical to work from the most likely solution to the least likely solution. And if you still can’t understand Occam’s Razor, then let me put it in simpler terms:
      Occam’s Razor=Heuristic (Educated Guessing) tool for determining likely theories, and potentially ordering them.
      Occam’s Razor=/= and has never been equal to a law of logic. It’s a tool for finding what we should analyze, not for saying what is true.

  3. I Doubt It says:

    For good examples of this concept, visit The Anomalist web site ( While this site used to be a fun read for weird world news (rains of frogs, ball lightning, etc.), it has now become a clearinghouse for poorly-written blog posts about unconfirmed anomalous and paranormal events. The signal to noise ratio now makes it pretty worthless.

    Steve, this was a great post. I would really appreciate more of this and a list of references to follow through and learn more. (Please?)

  4. tmac57 says:

    To me people like Hoagland and his fellow ‘true believers’, seem like young children playing fanciful make-believe games. Their rhetoric may be more sophisticated than a child, but their logical underpinnings aren’t. “Look! Here comes the aliens swooooosh! Over there, it’s Saturn! Looks like a good place to make a moon-craft! Crrrrunnnnch! Wow ,that looks great, but let’s add some tetrahedral messages ! Cool. That’ll keep um guessing.”

  5. I suspect Hoagland was sincerely moonswoggled by his original ‘discovery’ of the Face On Mars, but it got him so much in the way of books, magazine articles, radio and TV interviews, Ufool conference appearances, and general notoriety as an ‘expert’ (in a field that knows nothing) that he now knowingly mines additional horsehockey wherever he can hopefully develop his next ufological franchise.

  6. Cambias says:

    My nephew gave me a copy of Hoagland’s Moon book (“Dark Mission”) and at first I took it for a very clever parody of pseudoscience. His “images” are “enhanced” by scanning and cranking up the contrast, turning things like minor brightness variations and lens flares into weird geometric shapes — which he then proudly points to as “alien artifacts.” They’re artifacts, all right, but hardly alien.

    Since nobody could be that stupid, either Mr. Hoagland is far gone in self-delusion, or he’s playing the game with tongue in cheek because it has become how he makes his living.

  7. MadScientist says:

    @Max: Even Newton was aware of the problem of Mercury’s orbit. Copernicus’ measurements were more than adequate to demonstrate an insufficiency with Newton’s laws and Keppler is very likely to have been familiar with the problem in his own analysis of the data (even though he didn’t know of Newton’s laws as such). However, despite Mercury, between Newton and Kepler an awful lot was explained; other models of the solar system not only did not explain anything (or at best offered a pretty lame explanation) but they were more complex than what Newton and Kepler had to offer – so applying Ockham’s Razor, the laws of Netwon and Kepler win out despite the anomaly with Mercury. Of course if you were talking specifically of Mercury, then Einstein obviously wins because he explains what Newton couldn’t.

  8. Max says:


    Urbain Le Verrier died convinced he discovered planet Vulcan. A believer in Newton’s paradigm could always argue that we need to keep searching for Vulcan and eliminating all possibilities within Newton’s paradigm before switching to Einstein’s paradigm.

  9. Just ask Mr. Spock.

  10. Hmmm says:

    If the Face on Mars is really just a natural formation, then why did NASA originally lie about having taken pictures to disprove it back when it was first noticed? They claimed there was another picture from a different angle at a different time that showed it clearly as a natural formation (immediately poo-pooing the possibility that the feature could be artificial), but then had to admit that (at the time) there was no such picture showing that! How SCIENTIFIC was it of NASA to dismiss the “Face” immediately by FALSELY claiming that there was evidence which would disprove it?! Sounds pretty biased & unscientific to me.

    If it WAS a face, or even the strong CHANCE of it being a face, then they would have lied about it right away, because one thing is for sure: if NASA and/or the U.S. government found evidence of alien civilizations on some extra-planetary body (or of UFOs in our vicinity), they sure as hell wouldn’t just come out and tell the American public. They consistently strive to keep the average American believing heaps of monumental lies, so it’s not like there’s some real reverence for Truth & Transparency, here!

    You really should consider the possibility of such things, because some of these matters might be closer to the truth than one might first think–and the powers-that-be aren’t exactly interested in educating or enlightening their serfs, so don’t count on the truth being given openly to you on the evening news.

    • tmac57 says:

      “because one thing is for sure: if NASA and/or the U.S. government found evidence of alien civilizations on some extra-planetary body (or of UFOs in our vicinity), they sure as hell wouldn’t just come out and tell the American public.”
      I don’t believe for a second that your statement is “for sure”, and if you do, then one thing IS for sure;you are not a very good critical thinker.

      • Wrong says:

        It would entirely justify NASA and SETI forever. I’d think an announcement like that would be on par with: “We actually found WMDs in Iraq!”.

  11. Adam says:

    The response from “Hmmm” is a good example of pseudoscientific response to data – “it’s all faked when it contradicts my theory”. A classic example is Zechariah Sitchin claiming markings from construction workers in Khufu’s tomb were faked because he “knew” the Anunanki had built the Pyramids.

  12. Hmmm says:

    Maybe YOU people should read more carefully, because you ignored the 2 main points of

    First, to “tmac”, please tell me why you think the U.S. Government would come out and tell the public if they found aliens. WHY would they do this?

    And to Adam—did you even read my post? I brought up a valid point regarding NASA’s less-than-honest approach to dismissing the “Face.” Where did I say, “It’s all faked,”?

    Both of you ignored the heart of my comment and jumped on me as not being a critical thinker. HMMMMM. Maybe you should read more carefully. Or maybe this is yet another dopey blog that’s not even worth reading, because it’s just a circle-jerk for nerds who want to reinforce each other’s trite opinions without having to bother DISCUSSING things.

    • tmac57 says:

      I can’t see any reason why the government wouldn’t be more than willing to say they had discovered real evidence of extra-terrestrials. That would be an incredible discovery.
      Why don’t you just go with the “dopey blog not worth reading”, and take your ad-homiem attacks elsewhere?

  13. undrgrndgirl says:

    is it not possible, that skepticism itself is a mental pitfall? that despite the best intentions of scientific methods, those methods are also mistaken?

    • Wrong says:

      It works. That’s it. You see something, you think something, you find evidence to support a hypothesis, and formulate theories. It’s testable, provable, convergent and logical.
      I don’t see how methodological Naturalism is a shortfall in any way.
      I can’t think of any other approach that logically works, and if we do not have logic, then I guess everything falls apart to an extent. So I guess logic and reasoning are axiomatic then. And everything else follows. Unless someone has a better idea? (I’m wondering what you have to take as axiomatic so that the Scientific Method naturally follows).

  14. “is it not possible, that skepticism itself is a mental pitfall? that despite the best intentions of scientific methods, those methods are also mistaken?”

    In that very little can be proved impossible, the better, truer judgment would be rating the probability that scientific skepticism and scientific method are illusory, mere mental pitfalls. I would rate that probability at virtually nil.

    I say this bevause it works. It’s testable and one can arrive at an objective conclusion. One might cogitate an application of a theory for unpowered human flight that may or may not be total hogwash, a perfect example of a ‘mental pitfall’, but if the model works and the human-piloted hang glider goes aloft and remains there, safely returning to earth, all according to plan, that’s a pretty good endorsement of the science that went into it. Of course, we have literally millions upon millions of these full endorsements.

    To be correct, any hypothesis stating that skepticism and science are illusory, a mental pitfall of humans fooling themselves, also has to explain why it nonetheless works.

  15. Hmmm
    - Do you have a reference for the claim that NASA lied about another photo? It’s hard to respond to that without a source. I suspect the story is either different or more complex than you think.

    - Don’t ignore simple human error before concluding there is a conspiracy.

    - NASA would have a huge incentive to go public with information about possible alien artifacts on Mars. Think what that would do for their budget, and for public support for more Mars missions.

    - You ask for a reason why they would tell the truth (and I just gave you one), but you have not provided a reason why they would lie.

  16. Ray says:

    I’ve been extremism on both sides of the fence when it comes to discussions of anomalous phenomena, in terms of true dis-believers digging in their heels almost as much as the true believers. This article would make it sound as though the skeptics are the rational, even-keeled ones, but I’ve seen a few too many cases of knee-jerk debunking going on–not as bad as what Hoagland does, thank God, but bad enough.

    Case in point: I find Dean Radin’s work on anomalous interactions beteen humans and machines deeply impressive, and Radin seems like a thoughtful, scientifically-minded fellow–yet the skeptical community has treated him like something of a crackpot (when they choose to acknowledge him at all), and the critical studies I’ve read of his work have not only seemed unconvincing, but have struck me as a slippery, defensive upholding of the status quo.

    Similarly, I’ve seen skeptical attacks on researchers who stand to profit from their promotion of anomalous phenomena (UFOs, Bigfoot, etc.), and that’s a perfectly legitimate criticism; yet that sword cuts both ways, i.e., if someone makes their living debunking anomalous phenomenon (say, the publisher or editor of a skeptical magazine), why should we trust their judgment of the evidence to be any less biased for reasons of profit? After all, if they were to start publishing articles favorable to these things, they’d be out of a job. What’s good for the goose…

  17. W says:

    tmac57 says:
    May 2, 2009 at 12:01 pm
    I can’t see any reason why the government wouldn’t be more than willing to say they had discovered real evidence of extra-terrestrials. That would be an incredible discovery.
    Why don’t you just go with the “dopey blog not worth reading”, and take your ad-homiem attacks elsewhere?

    …sounds like someone got their feelings hurt…waaa….waaa…waaa…somebodyshould get tmac57(Tracy McGraddy?!?) some tissues, cuz he’s upset…

    • Wrong says:

      It sounds like you’re a little slow and hard of cognitive processing, so I’ll put it simply: Using a Name that is not a name is cowardly.
      Also, if someone believes the blog is not worth reading, why are they wasting time on it? If it were bad but worth reading, sure, criticism helps. But if it’s not worth reading it’s beyond help, and arguing with those you don’t agree with gets you nowhere if you think they can’t be convinced.
      If someone dismisses your argument as a bunch of nerds reinforcing each others trite opinions without proving you wrong, that’s ad hominem. It’s a claim about them, unrelated to the issue, which does not make them right. It’s: you’re wrong, because you’re a member of this sites community, and I dismiss this site out of hand.

      Despite the fact that tmac had pointed out something obvious and said that accusing NASA of lying is a pointless conspiricay (Prove it if you think it’s actually happening), and to prove the statement he relies on as fact, that as in the movies, the government would hide aliens once they found them.

      I’d accuse you of being HMMMM, but I don’t have proof, but I’ll imply it: You’re either HMMMM, or a rude and stupid person who responded to a post without thinking. I think that’s a reasonable dichotomy.
      (Also, going to (JREF I would assume) to find a person’s real name, and use it to address them is a pathetic implied threat. Grow some balls and use your name if you want to call out others.

  18. Jeff says:

    So wait, he is relying on NASA, what he considers an unreliable source, to generate evidence in the first place but rejects the more detailed, harder to forge, high resolution photos they later come out with? That is the exact opposite of a hypothesis.

  19. vincentvoll says:


    What about the mirror riddled with anomalies thats advertised in theoretical phys. ?. What about the social anomalies, where is the proletariat ?. What about the political anomalies, this strange alliance between leadership and the syndrome of Down ( in our country we have this thing called Geert Wilders ). How do we join the order of things, anyway ?.

    Uit de belaagde landen
    Greetz Vincent Voll.