Through the looking glass

Regular readers of Skeptophilia may remember that a couple of weeks ago, I attempted to write a post on the odd superstitions surrounding mirrors, but got sidetracked over and over.

In a curious almost-synchronicity, today I ran into an article about how artificial intelligence can learn how to detect mirror-reversed images, even when they don't have such obvious cues as text to go by.  So I figured I ought to give another shot at addressing the topic of mirrors, more seriously this time.

Mirror reversal is a peculiar phenomenon, and I recall when I was in introductory physics in college and we were studying the optics of mirrors and lenses, I spent an inordinate amount of time trying to figure out why a flat mirror reverses an image right-to-left but not top-to-bottom.

The answer, which many of you probably already know, is that mirrors don't reverse right-to-left, exactly; they reverse back-to-front.  This has the effect of a right/left reversal because it's like you're looking at the object from the other side (imagine the object in question was transparent, but you could still see its contours, and the reasoning becomes easier).

Look, I can prove it to you.  Stand in front of a mirror.  What it seems like is that there is another person who looks exactly like you standing behind a clear piece of glass, at the same distance from the glass as yourself and facing you.  Now, think about what it would be like if you were to join him/her -- go behind the mirror.  To get there, you would have to walk behind the glass and turn 180 degrees about the vertical axis to face you.  If you did that, your left hand would be opposite his/her right hand, and vice versa.  What actually happened is that your reflection didn't do a 180 degree turn.  It was reversed front to back with no rotation at all.  You're seeing yourself not so much reversed as turned inside-out.

Interestingly, there is a mirror that reverses objects top to bottom -- a concave mirror.  It also creates an image that appears to be in front of the mirror, not behind it, and in the right setup, the image seems to be floating in space (which is why the physicists call concave mirror images "real images," and ones that are behind the mirror -- as in flat and convex mirrors -- "virtual images").

[Image is in the Public Domain]

Whether concave mirrors reverse text is left as an exercise for the reader.

But what brought me to the subject of mirrors (again -- although my first attempt was pretty pathetic) is the paper "Visual Chirality," by Zhiqiu Lin, Jin Sun, Abe Davis, and Noah Snavely, of Cornell University, which was presented at the 2020 Conference on Computer Vision and Pattern Recognition.  What the researchers did was to use a trainable artificial intelligence program to analyze images, some of which were mirror-reversed and others which were not, to see if it was possible to determine reversal without using such giveaways as text, analog clocks, and so on.

And they got pretty good at it.  Some of the cues it picked up on were of the "oh, yeah, of course" type, such as looking at where the buttons were on a button-down shirt.  (Buttons tend to be on the right side -- although years ago women's shirts used to button from the other side, most shirts for either gender now usually have the buttons on the right.)  Wristwatches were also a giveaway, even when the faces weren't visible; most people wear them on the left wrist.  People carrying phones usually had them in their right hands, probably attributable to the fact that between seventy and eighty percent of us are right-handed.

But there were some curious ones.  Turns out the algorithm figured out that when people are in face-forward photographs but not looking directly at the camera, they usually gaze to the left.  Men with facial hair also were easy for the software to pick out when reversed -- the researchers suspect it has something to do with the way men trim their beards (perhaps also connected to using the right versus the left hand to do so), but what exactly the algorithm was picking up on, the researchers aren't certain.

"It’s a form of visual discovery," said study co-author Noah Snavely.  "If you can run machine learning at scale on millions and millions of images, maybe you can start to discover new facts about the world."

After training, the algorithm was getting the answer right eighty percent of the time even when all the obvious giveaways were removed -- not a bad score.  The study has applications in the analysis of images, and detection of when those images have been doctored or altered.

What it puts me in mind of is the facial asymmetry that most humans have, something well-known to portrait artists.  Take a sheet of paper, and stand in front of your bathroom mirror.  Relax your facial muscles -- try for a neutral expression -- and cover up first one, then the other, half of your face with the paper.  You'll be surprised at how different they look -- angle of the mouth, position of the eyebrows, and so on can vary greatly.  (There was an interesting study a while back that correlated facial symmetry with our perception of beauty -- and found that of the people tested, Denzel Washington had the most perfectly symmetrical face.  It may be that symmetry is an indication of freedom from some genetic flaws that influence skeletal development -- making symmetrical people good bets for producing healthy children -- but that, of course, is speculation.)

Anyhow, it's an interesting finding.  But I'm definitely going to pay more attention next time I trim my facial hair.

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This week's Skeptophilia book recommendation of the week is pure fun, and a great gift for any of your friends who are cryptid fanciers: Graham Roumieu's hilarious Me Write Book: It Bigfoot Memoir.

In this short but hysterically funny book, we find out from the Big Guy's own mouth how hard it is to have the reputation for being huge, hairy, and bad-smelling.  Okay, even he admits he doesn't smell great, but it's not his fault, as showers aren't common out in the wilderness.  And think about the effect this has on his self-image, not to mention his success rate of advertising in the "Personals" section of the newspaper.

So read this first-person account of the struggles of this hirsute Everyman, and maybe even next time you're out hiking, bring along a little something for our australopithecene distant cousin.

He's very fond of peach schnapps.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Viral nonsense

I'm going to issue another plea to please please puhleeeezz check your sources before posting stuff.

This goes double for the viral meme type shit you see every single day on social media.  Most of that stuff -- and I'm not talking about the ones that were created purely for the humor value -- is the result of someone throwing together a few intended-to-be-pithy quotes with a photograph downloaded from the internet, so it's only as accurate as the person who made it.

In other words, not very.

Here's an example that I'm seeing all over the place lately:

Okay, let's take a look at this piece by piece.

1. Tilapia has bones.  Anyone who's ever prepared tilapia for cooking knows this.
2. It is an ordinary fish, with not only bones, but skin.  Note that the photograph of the damn fish right in the image shows that it has skin.
3. You can certainly overcook it, like you can with anything.  Leave it in the oven for three hours, and you'll have fish jerky.
4. Tilapia is found in the wild.  It's native to Africa.  Most tilapia being sold is raised on fish farms, so that part is correct, showing the truth of the old adage that even a stopped clock is right twice a day.
5. I'm not even sure what "the Algae & lake plant, or replaced by gmo soy & corn" means.  Maybe they're trying to say that farmed tilapia is sometimes fed genetically-modified soy or corn-based products, which could well be, but is completely irrelevant even if it's true.
6. Eating tilapia is not worse than bacon and hamburgers.  It's low in overall calories and saturated fats, and is a good source of protein.
7. It'd be odd if tilapia were unusually high in dioxins, as dioxins are produced by such activities as burning plastic.  In fact, according to Medical News Today, due to EPA regulations, the amount of dioxins in the environment in the USA is 90% reduced from what it was thirty years ago -- and they recommend eating fish as a way of decreasing the amount of dioxin in your diet.
8. Dioxin "can take up to 11 years to clear?"  Not ten or twelve?  Okay, now you're just pulling this out of your ass.
9. You are not killing your family by serving them tilapia.  For fuck's sake.

Then, there's this nonsense that I've seen over and over:

Just out of curiosity, how desperate do you have to be to photoshop Trump into a photograph in order to make him look like a compassionate human being?  I mean, I get that there's not much else you can do.

But still.

If you're curious, the photograph doesn't even come from Hurricane Florence (as the post claims, along with a snarky "You won't see this on the news -- share with everyone!" caption).  It comes from the 2015 flooding in Texas.  Here's the unaltered photo:

I do think it's kind of inadvertently hilarious that when they photoshopped Trump into the picture, they made it look like he's handing the guy a MAGA hat.  "Hey, thanks for being here.  I was expecting more people to show up and applaud me, but I guess the killer flood swept them away.  Here, have a hat."


Then there's latest craze from Gwyneth "Snake Oil" Paltrow's company Goop, which is: "wearable stickers."  Me, I thought all stickers were wearable in the sense that you can stick them to your skin.  Thus the name.

But that's not what she's talking about.  These stickers, which are a "major obsession around Goop HQ," are supposed to "rebalance the energy frequencies in your body."

Whatever the fuck that means.

Here's a photo of a woman with three of them on her arm:

And the sales pitch:

Human bodies operate at an ideal energetic frequency, but everyday stresses and anxiety can throw off our internal balance, depleting our energy reserves and weakening our immune systems.  Body Vibes stickers come pre-programmed to an ideal frequency, allowing them to target imbalances.  While you’re wearing them—close to your heart, on your left shoulder or arm—they’ll fill in the deficiencies in your reserves, creating a calming effect, smoothing out both physical tension and anxiety.  The founders, both aestheticians, also say they help clear skin by reducing inflammation and boosting cell turnover.

Which is nearly "tilapia is killing you" levels of bullshit.  Just to point out one thing -- because even explaining this far is giving Paltrow far more credit than she deserves -- there's no such thing as an "energy frequency" because energy and frequency are two entirely different things.  Saying "energy frequency" is like asking someone what their "weight speed" is.

So I'm begging you.  Do a quick search online before reposting this stuff.  There are a ton of fact-check and skeptical analysis sites where you can at least do a first-order look at whether there's any truth to it.  The only other way to approach this is to comment "THIS IS NONSENSE" every time you see things like this, and that's beginning to feel a little like trying to patch the hole in the Titanic with duct tape.

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This week's recommendation is a classic.

When I was a junior in college, I took a class called Seminar, which had a new focus/topic each semester.  That semester's course was a survey of the Book Gödel, Escher, Bach: An Eternal Golden Braid by Douglas Hofstadter.  Hofstadter does a masterful job of tying together three disparate realms -- number theory, the art of M. C. Escher, and the contrapuntal music of J. S. Bach.

It makes for a fascinating journey.  I'll warn you that the sections in the last third of the book that are about number theory and the work of mathematician Kurt Gödel get to be some rough going, and despite my pretty solid background in math, I found them a struggle to understand in places.  But the difficulties are well worth it.  Pick up a copy of what my classmates and I came to refer to lovingly as GEB, and fasten your seatbelt for a hell of a ride.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]

Picture perfect

Neil deGrasse Tyson once quipped that photographic evidence was no longer reliable because Photoshop probably had an "Add UFO" button.  It's an exercise I like to demonstrate with my Critical Thinking class; after watching a documentary about fake ghost photographs, they have an optional assignment to try to create the most realistic-looking and/or scary UFO, ghost, or other paranormal photograph they can.

The results are so creepy -- and so easy to make, if you have access even to rudimentary digital image modification software -- that the wall of photographs we display afterwards makes a real impact.

"I'll never believe a photograph is real again," one student said in an awed voice while looking at the collection of ghosts, spacecrafts, and Bigfoots.

Mont St. Michel is beautiful, isn't it?  Yes, but the water and the reflection were all added to the image via Photoshop.  [image courtesy of photographer Andrés Nieto Porras and the Wikimedia Commons]

While that is honestly a bit of an overreaction, it's always best to be on the suspicious side whenever anyone claims a photograph as proof for a claim.  Not only are altered images easy to make -- as a paper just released last week in Cognitive Research: Principles and Implications shows, humans are kind of lousy at differentiated between retouched and unretouched photos.

In "Can People Identify Original and Manipulated Photos of Real-World Scenes?", authors Sophie J. Nightingale, Kimberley A. Wade, and Derrick G. Watson set up a series of tests in which subjects were asked if they could detect digitally-altered photographs that had impossibilities -- shadows pointing the wrong way, geometrical inconsistencies, features missing (such as removing the crosswise structural supports from a suspension bridge) or added (such as tables with extra legs).  They were given ten photographs, some altered and some not, and as much time as they wanted to study them, and then were asked to identify which (if any) had been manipulated, and if so, how.

And people, in general, were terrible at it.  The authors write:

In two separate experiments we have shown, for the first time, that people’s ability to detect manipulated photos of real-world scenes is extremely limited.  Considering the prevalence of manipulated images in the media, on social networking sites, and in other domains, our findings warrant concern about the extent to which people may be frequently fooled in their daily lives.  Furthermore, we did not find any strong evidence to suggest that individual factors, such as having an interest in photography or beliefs about the extent of image manipulation in society, are associated with improved ability to detect or locate manipulations. 

Recall that we looked at two categories of manipulations—implausible and plausible—and we predicted that people would perform better on implausible manipulations because these scenes provide additional evidence that people can use to determine if a photo has been manipulated. Yet the story was not so simple...  [E]ven when subjects correctly identified the implausible photo manipulations, they did not necessarily go on to accurately locate the manipulation.  It is clear that people find it difficult to detect and locate manipulations in real-world photos, regardless of whether those manipulations lead to physically plausible or implausible scenes.

Which, of course, should be enough to give anyone pause.  Our capacity for recognizing when we've been fooled is far poorer than we tend to believe.

And the more sophisticated the digital manipulation software gets, the worse this problem will become.  Early digital photography programs were nothing short of crude, and attempts to mess around with the image always left traces that a discerning eye could see.  But now?  It's telling that a bunch of inexperienced high school students could, in short order, produce images that were absolutely convincing.

Think of how much could be done by people who were experts in digital image modification.

There's even an iPhone app that adds six-pack abs and broader shoulders to your photo.  Wouldn't it be nice if it were this easy in real life?

So we might well be approaching the "Trust Nothing" stance of my student from last year.  I hate to promote cynicism, but honestly, casting a wry eye on any photographic evidence is probably a smart thing place to start.   We're not quite at the point of having an "Add UFO" button -- but it's not far away.