The interstellar lighthouse

It's funny the questions you don't think to ask.  You find out something, accept it without any objections, and only later -- sometimes much later -- you stop and go, "Wait a moment."

That happened to me just yesterday, about a topic most of us don't ponder much, and that's the peculiar astronomical object called a neutron star.  It was on my mind not by random chance -- even I don't just sit around and say, "Hmm, how about those neutron stars, anyway?" -- but because of some interesting new research (about which I'll tell you in a bit).

I first learned about these odd beasts when I took a class called Introduction to Astronomy at the University of Louisiana.  The professor, Dr. Whitmire, explained them basically as follows.

Stars are stable when there's a balance between two forces -- the outward pressure from the heat generated in the core, and the inward pull because of the gravity exerted by the star's mass.  During most of a star's life, those two are in equilibrium, but when the core exhausts its fuel, the first force diminishes and the star begins to collapse.  With small stars like the Sun, the collapse continues until the mutual repulsion of the atoms' electrons becomes a sufficient force to halt it from shrinking further.  This generates a white dwarf. 

In a star between 10 and 29 times the mass of the Sun, however, the mutual electric repulsion isn't strong enough to stop the collapse.  The matter of the star continues to fall inward until it's only about ten kilometers across -- a star shrunk to the diameter of a small city.  This causes some pretty strange conditions.  The matter in the star becomes unimaginably dense; a teaspoon of it would have about the same mass as a mountain.  The pressure forces the electrons into the nuclei of the atoms, crushing out all the space, so that what you have is a giant electrically-neutral ball -- effectively, an enormous atomic nucleus made of an unimaginably huge number of neutrons.

The first neutron star ever discovered, at the center of the Crab Nebula [Image is in the Public Domain, courtesy of NASA/JPL]

The immense gravitational pull means that the surface of a neutron star is the smoothest surface known; any irregularities would be flattened out of existence.  (It's worth mentioning that even the Earth is way smoother than most people realize.  The distance between the top of Mount Everest and the bottom of the Marianas Trench is less, as compared to its size, than the topographic relief in a typical scratch on a billiard ball.)

So far, so good.  But it was the next thing Dr. Whitmire told us that should have made me pull up short, and didn't until now -- forty years later.  He said that as a neutron star forms, the inward collapse makes its rotational speed increase, just like a spinning figure skater as she pulls in her arms.  Because of the Conservation of Angular Momentum, this bumps up the rotation of a neutron star to something on the order of making a complete rotation thirty times per second.  A point on the surface of a typical neutron star is moving at a linear speed of about one-third of the speed of light.

Further, because neutron stars have a phenomenally large magnetic field, this creates two magnetic "funnels" on opposite sides of the star that spew out jets of electromagnetic radiation.  And if these jets aren't aligned with the star's spin axis, they whirl around like the beams of a lighthouse.  A neutron star that does this, and appears to flash on and off like a strobe light, is called a pulsar.

This was the point when the red flags should have started waving, especially since I majored in physics and had taken a class called "Electromagnetism."  One of the first things we learned is that Scottish physicist James Clerk Maxwell discovered that magnetic fields are generated when charged particles move.  So how can a neutron star -- composed of electrically-neutral particles -- have any magnetic field at all, much less one so huge?  (The magnetic field of a typical neutron star is on the order of ten million Tesla; by comparison, one of the largest magnetic fields ever generated in the laboratory is a paltry sixteen Tesla, but was still enough to levitate a frog.)

The answer is a matter of conjecture.  One possibility is that even though a neutron star is neutral overall, there is some separation of charges within the star's interior, so the whirling of the star still creates a magnetic field.  Another possibility is that since neutrons themselves are composed of three quarks, and those quarks are charged, neutrons still have a magnetic moment, and the alignment of these magnetic moments coupled with the star's rotation is sufficient to give it an overall enormous magnetic field.  (If you want to read more about the answer to this curious question, the site Medium did a nice overview of it a while back.)

So it turns out that neutron stars aren't the simple things they appeared to be at first.  Not that this is much of a surprise -- seems like every time we answer one question in science, it generates three new ones.  What brought this up in the first place was yet another anomalous observation about neutron stars, described in a series of papers this past week in Astrophysical Journal Letters.  The conventional wisdom was that a neutron star's magnetic field would be oriented along an axis (which, as noted above, may not coincide perfectly with the star's spin axis).  This means that it would behave a bit like an ordinary magnet, with a north pole and a south pole on geometrically opposite sides.

That's what astronomers thought, until they found a pulsar with the euphonious name J0030+0451, 1,100 light years away in the constellation of Pisces.  Using the x-ray jets from the pulsar -- which should be aligned with its magnetic field -- they mapped the field itself, and found something extremely strange.

Instead of two jets, aligned with the poles of the magnetic field, J0030+0451 has three -- and they're all in the southern hemisphere.  One is (unsurprisingly) at the southern magnetic pole,  but the other two are elongated crescents at about sixty degrees south latitude.

To say this is surprising is an understatement, and the astronomers are still struggling to explain it.

"From its perch on the space station, NICER [the Neutron star Interior Composition Explorer] is revolutionizing our understanding of pulsars," said Paul Hertz, astrophysics division director at NASA Headquarters in Washington.  "Pulsars were discovered more than fifty years ago as beacons of stars that have collapsed into dense cores, behaving unlike anything we see on Earth."

It appears that we still have a way to go to fully explain how they work.  But that's how it is with the entire universe, you know?  No matter where we look, we're confronted by mysteries.  Fortunately, we have a tool that has proven over and over to be the best way of finding answers -- the collection of protocols we call the scientific method.  I  have no doubt that the astrophysicists will eventually explain the odd magnetic properties of pulsars.  But the way things go, all that'll do is open up more fascinating questions -- which is why if you're interested in science, you'll never run out of things to learn.

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This week's Skeptophilia book recommendation is pure fun, and a perfect holiday gift for anyone you know who (1) is a science buff, and (2) has a sense of humor.  What If?, by Randall Munroe (creator of the brilliant comic strip xkcd) gives scientifically-sound answers to some very interesting hypothetical questions.  What if everyone aimed a laser pointer simultaneously at the same spot on the Moon?  Could you make a jetpack using a bunch of downward-pointing machine guns?  What would happen if everyone on the Earth jumped simultaneously?

Munroe's answers make for fascinating, and often hilarious, reading.  His scientific acumen, which shines through in xkcd, is on full display here, as is his sharp-edged and absurd sense of humor.  It's great reading for anyone who has sat up at night wondering... "what if?"

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

The origin of Antarctican

Here's a bit of writing that should be familiar to most of you.

Fæder ure þu þe eart on heofonum; Si þin nama gehalgod to becume þin rice gewurþe ðin willa on eorðan swa swa on heofonum.  Urne gedæghwamlican hlaf syle us todæg, and forgyf us ure gyltas swa swa we forgyfað urum gyltendum; and ne gelæd þu us on costnunge ac alys us of yfele soþlice.

Recognize it?

It's the Lord's Prayer in English as it was spoken only a thousand years ago.  My guess is a lot of you had no idea what it was (although I have a number of regular readers who, like me, are aficionados of obscure languages; y'all don't count).  There are a few words that haven't changed in that time -- in this passage, only "us" and "and" -- but most have changed dramatically.  There are even a couple of letters that don't exist in Modern English, strikingly ð (pronounced like the first consonant in there) and þ (the first consonant in thin), both of which are written as "th" in Modern English.

Languages change, and they change at different rates.  Old Norse and Modern Icelandic are really more like different dialects of the same language than they are like different languages, even though just as much time has passed between Old Norse and Modern Icelandic as between Old English and Modern English.  There are sometimes sudden jumps -- the Norman Conquest in the 11th century and the Great Vowel Shift in the 15th are the two best-known examples from English, although the Viking Invasions of the 9th and 10th centuries had a significant effect, too, not only on vocabulary and pronunciation, but on place names.  (The subject of my master's thesis was how the Vikings affected Old English and Old Gaelic, which should win an award for research with no practical applications whatsoever.)

[Image licensed under the Creative Commons M. Adiputra, Globe of language, CC BY-SA 3.0]

These huge leaps are uncommon, however, and most language change progresses slowly and gradually.  The parallels to biological evolution are obvious, and the argument over whether language change is smooth or goes by fits-and-starts is just as silly as the corresponding argument over evolutionary gradualism vs. punctuated equilibrium.  It's not that one is the correct model and the other is not; both are correct, just in different circumstances.

The big jumps, of course, are easier to detect.  The effects of the Norman Invasions of England were profound, as words were adopted from French and then bent to conform to English phonological rules.  It's why we have so many pairs of words for food, one for its living farmyard state and the other for when it's on the table.  Cow/beef; sheep/mutton; pig/pork; chicken/poultry; calf/veal.  In each case, the first is from Old English (because the lower socioeconomic class Anglo-Saxons were the ones on the farm raising the animals) and the other from French (because their Norman overlords only saw the animal after being cooked).

But the similarity between language evolution and biological evolution runs a lot deeper than its pace.  Like evolutionary change in populations, language "speciation" not only needs small changes (corresponding to genetic mutations), selection (some forms succeeding and others disappearing), and some form of isolation.  Isolated populations take off on their own paths, often very different from the parent population, and because of the small number of individuals often do so more quickly than a large group would -- a sort of linguistic genetic drift.  (A good example is the Cornish language, which branched off from Welsh as a dialect in Roman times; by the 13th century, when the earliest extant examples of Cornish were written down, the two had evolved into two no longer mutually intelligible languages.)

This topic comes up because of some recent amazingly cool research by Jonathan Harrington, Michele Gubian, Mary Stevens, and Florian Schiel of the University of Munich, in which linguists have -- perhaps for the first time -- seen the beginnings of a dialect forming as it happens.  In "Phonetic Change in an Antarctic Winter," published last month in the Journal of the Acoustical Society of America, we find out about a study of the people who were isolated at the field station of the British Antarctic Survey during the long, frigid Antarctic winter, and about whom the researchers found something astonishing.

They started with a variety of accents, coming as they did from different English-speaking regions, but over the six months they were isolated, their accents began to converge into a distinct way of speaking unlike any of the "parent" accents.  Vowel sounds, especially, merged.  As an example, some of the speakers started out pronouncing the vowel sound in the word food as a front vowel (this is more common in British English), whereas others used a back vowel (more common in American English).  After only six months, the two sounds had converged, and everyone pronounced the sound as a middle vowel about halfway between the two extremes.

The authors write:

An acoustic analysis was made of the speech characteristics of individuals recorded before and during a prolonged stay in Antarctica.  A computational model was used to predict the expected changes due to close contact and isolation, which were then compared with the actual recorded productions.  The individuals were found to develop the first stages of a common accent in Antarctica whose phonetic characteristics were in some respects predicted by the computational model.  These findings suggest that the phonetic attributes of a spoken accent in its initial stages emerge through interactions between individuals causing speech production to be incrementally updated.

Of course, since the field station isn't permanently occupied by the same people, it's pretty likely that when the eleven test subjects went back to their homes (eight from various regions of England, one from the United States, and the other two -- who were not native speakers -- to Iceland and Germany) their accent reverted to the pronunciations typical for their milieu.

But it does give us a lens into how dialects form in other less contrived situations, and you can easily see how -- given enough time -- you might end up with modes of speaking so different that they would no longer be mutually intelligible.

Even, perhaps, to the point that "Fæder ure þu þe eart on heofonum" becomes "Our Father, who art in heaven."

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This week's Skeptophilia book of the week is brand new; Brian Clegg's wonderful Dark Matter and Dark Energy: The Hidden 95% of the Universe.  In this book, Clegg outlines "the biggest puzzle science has ever faced" -- the evidence for the substances that provide the majority of the gravitational force holding the nearby universe together, while simultaneously making the universe as a whole fly apart -- and which has (thus far) completely resisted all attempts to ascertain its nature.

Clegg also gives us some of the cutting-edge explanations physicists are now proposing, and the experiments that are being done to test them.  The science is sure to change quickly -- every week we seem to hear about new data providing information on the dark 95% of what's around us -- but if you want the most recently-crafted lens on the subject, this is it.

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

A fight over dates

One of the most frustrating things about science, from the point of view of non-scientists, is that sometimes we have to say "we simply don't know the answer to that yet."

Of course, I'm sure it's frustrating enough to the scientists as well, but at least they should be used to it.  Science is always pushing at the boundaries of what we know, and using evidence and logic to find explanations.  It's inevitable that sometimes even a significant amount of evidence is insufficient to reach a conclusion.  At that point, the only honest thing to say is "we don't know, and may never know."

This drives a lot of people nuts.  The attitude is that because science has proven to be pretty damn good at finding answers, that it should have a 100% hit rate.  Meteorologists can't always accurately predict the track or intensity of storms?  Ha, I'd like to have a job where I could be wrong half the time and still get paid!  The promising new cancer drug turns out not to work in vivo?  Don't listen to the medical professionals, they'll say something is good for you today and then say the opposite tomorrow.  This fault is at risk of an imminent earthquake?  Okay, then tell me when, down to the hour and minute, so I can plan ahead.

Otherwise, what good are you scientists, anyhow?

It all comes from a fundamental misapprehension of the scientific process -- that it should provide certainty.  It'd be nice, but the real world usually doesn't cooperate, and sometimes even with their best efforts, the scientists have to admit befuddlement.

I ran into an especially good example of that a couple of days ago because of a dear friend, a history scholar and loyal reader of Skeptophilia, who asked me if I'd ever heard of Hueyatlaco and the Steen-McIntyre report.  She sent me a link from the rather loopy site s8int called "Details of the Steen-McIntyre Hueyatlaco Coverup" that (despite their seeming bent toward Ancient Astronauts explanations of things) gives the basics of the story -- and it's a pretty peculiar one, even when you don't credit any of the woo-woo trappings.

Now, keep in mind that until two days ago I'd never heard of this, so I still consider my own knowledge shallow and tentative, and I ask forgiveness for any mistakes or misapprehensions I have (and request a quick note if there's something in this post I can correct).  But this is what I've gathered.

Hueyatlaco is an archaeological dig site in the state of Puebla in central Mexico.  In the 1960s, an archaeologist named Cynthia Irwin-Williams was working at the site and uncovered stone tools and the bones of pre-glacial North American mammals (such as the woolly rhinoceros) that showed signs of having been butchered for meat.  Williams thought that such an early site deserved close attention, and she sent samples to the USGS for radioisotope dating.

The results were more than a little perplexing.  The date returned by the USGS was on the order of 250,000 years ago.  This predates modern Homo sapiens by a good fifty thousand years, so -- if the date was accurate -- the tools and the animal bones were associated not with modern humans, but with our predecessors, possibly the Neanderthals or Denisovans.  Also perplexing was that this would push back the earliest hominid occupation of North America not just by a little, but by a factor of sixteen!

It's understandable why the scientists found that hard to swallow.  The idea that humans (or their near relatives) had been in the Americas for 230-odd-thousand years longer than we thought they had, and had left no traces whatsoever during that time except at this one site, was difficult to believe.  So the natural conclusion was reached that the dating of the site was somehow askew.

Then repeated attempts kept giving the same age.

Hueyatlaco [Image licensed under the Creative Commons https://www.flickr.com/photos/xhumpty/, Valsequillo dam, CC BY-SA 2.0]

Most archaeologists stuck to their guns, and said the most parsimonious explanation was still that somehow the dating protocol was being applied incorrectly.  The samples were contaminated with older rocks, perhaps, which would give a systematic overestimate for the site's age.  Then, to muddy the waters further, there were allegations of a conspiracy to cover up the anomalous data.  The official report from the USGS simply dropped one of the zeroes, reporting the site's age as 25,000, not 250,000 years.  One of the archaeologists who'd been working on the site, Virginia Steen-McIntyre, was pressured to do her dissertation not on the perplexing Hueyatlaco data, but on more conventional research into volcanic ash strata.  Steen-McIntyre decided, however, that she wouldn't be silenced, and came out with a report of her own, taking apart the critics a point at a time -- and included a claim that she was harassed for being unwilling to stay silent.

Other scientists have tried (and failed) to resolve the odd data.  Biostratigrapher Sam Vanlandingham published two papers, in 2001 and 2004, first reconfirming the dating of the strata to not tens, but hundreds of thousands of years ago, and then (most startling of all) confirming this using microfossils of diatoms from contemporaneous sediments at the site -- and demonstrating that those diatom species had been extinct for at least eighty thousand years.

The upshot of it all is that we still don't have an answer.  Most archaeologists still doubt the existence of hominids in the Americas prior to the arrival of the ancestors of the Native Americans on the order of (at the most) twenty thousand years ago, and assert that there is not a single grain of evidence that the Neanderthals and Denisovans (or any other hominds, for that matter) ever made it to the Western Hemisphere.  But that leaves us with a puzzle -- multiple studies, cross-checked and confirmed, keep agreeing with the older date as found by Irwin-Williams, Steen-McIntyre, and others.

So if you've been waiting for an answer... well, that's it, folks.  We don't know.  It's one of the most curious archaeological puzzles I've ever run across, and at this point, the words I hear about it most often from reliable sources are "contentious" and "uncertain" and "controversial."  A lot of experts have a lot of opinions about it, but no one has been able to do either of two things -- explain how the dates could be correct when there's no evidence of hominids in the Americas at any time during the next two hundred thousand years, or explain how the dates could be incorrect when they've been independently corroborated multiple times.

As frustrating as it is, that's where we have to leave it if we're going to be scrupulously honest about things.  As good skeptics, we have to be willing to leave the question in abeyance, indefinitely if need be, for want of conclusive evidence to settle it.  In science, the answer "We don't know yet" is always the fallback when the data is insufficient to merit a conclusion -- however that offends our deep desire to be a hundred percent sure about everything in the universe.

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This week's Skeptophilia book of the week is brand new; Brian Clegg's wonderful Dark Matter and Dark Energy: The Hidden 95% of the Universe.  In this book, Clegg outlines "the biggest puzzle science has ever faced" -- the evidence for the substances that provide the majority of the gravitational force holding the nearby universe together, while simultaneously making the universe as a whole fly apart -- and which has (thus far) completely resisted all attempts to ascertain its nature.

Clegg also gives us some of the cutting-edge explanations physicists are now proposing, and the experiments that are being done to test them.  The science is sure to change quickly -- every week we seem to hear about new data providing information on the dark 95% of what's around us -- but if you want the most recently-crafted lens on the subject, this is it.

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

The family tree

One of the things I find endlessly fascinating about evolution is that we can use information we have in the present to infer what happened in the (very) distant past.

And I'm not even talking about fossils, here, as interesting as they are.  As Richard Dawkins points out, even if the entire fossil record ceased to exist, the evidence for evolution would still be overwhelming.  What I'm thinking about is the use of DNA to determine relationships between current species, and from that theorize about when their most recent common ancestor lived, and even what it might have looked like.

This comes up because of a recent paper in Nature that analyzed the genomes of over a thousand different species of plants and algae to construct the most detailed and accurate cladogram (which you can think of as a family tree) of the entire kingdom that has ever been created.  There are an estimated 500,000 species of plants currently in existence, so while this is still using a partial data set, it's pretty damned impressive.

"Some species began to emerge and evolve several hundreds of millions of years ago," said plant physiologist Professor Marcel Quint from the Institute of Agricultural and Nutritional Sciences at Martin Luther University Halle-Wittenberg, in an interview with Science Daily.  "However, today we have the tools to look back and see what happened at that time...   Some of these gene families have duplicated over the course of millions of years.  This process might have been a catalyst for the evolution of plants.  Having significantly more genetic material might unleash new capacities and completely new characteristics."

The results, as you might expect, provided a few surprises.  "We used to think that the greatest genetic expansion had occurred during the transition to flowering plants," said Martin Porsch, also from MLU-Halle-Wittenberg.  "After all, this group contains the majority of existing plant species today.  However, the new data reveal that the genetic foundations for this expansion in biodiversity had been laid much earlier.  The transition from aquatic to terrestrial plants was the starting point for all further genetic developments.  This development was the greatest challenge for plants, and so they needed more genetic innovations than ever before."

"We found an enormous increase in genetic diversity at the time of this transition, after that it reached a plateau," added Ivo Grosse, bioinformatician at MLU-Halle-Wittenberg, who co-authored the paper.  "From this time on, almost all of the genetic material was available to drive evolutionary progress and generate the biodiversity we see today."

So without further ado, here's their cladogram:

It confirmed something that I found fascinating when I first heard about it, back in the early 2000s -- that the division of flowering plants into "monocots" and "dicots" -- familiar to every high school biology student -- needed to be revisited, because "dicot" isn't a monophyletic clade -- all descended from a single ancestor that includes no other descendants.  It was found that the peculiar New Zealand species Amborella was technically a dicot (networked leaf veins, flower parts in fours or fives, two seed leaves) but was far more distantly related to other dicots than monocots (such as grasses, lilies, palms, and so on) were.

Amborella trichopoda [Image licensed under the Creative Commons Scott Zona from USA (original upload author), Amborella trichopoda (3065968016) fragment, CC BY 2.0]

When it was later found that the same was true of water lilies, it clued the geneticists in that there was something seriously amiss with our understanding of the family tree of plants.

So the new cladogram supports the older research, putting Amborella, water lilies, lotuses, and star anise as outgroups within the entire phylum of flowering plants; a self-contained clade with all the monocots next; and the rest of the dicots scattered along the remainder of the tree.

I know I'm a science nerd, and a little over-enthusiastic about genetics sometimes, but I think this research is amazingly cool.  The idea that we could look at a plant's DNA, here in 2019, and infer its relationship with other species from which it branched off hundreds of millions of years ago, is boggling.  It makes me wonder what other surprises are out there in the DNA of the nine-million-odd species of life on Earth -- and also realize that when it comes to understanding the other denizens with which we share the planet, we've only barely begun.

***********************

This week's Skeptophilia book of the week is brand new; Brian Clegg's wonderful Dark Matter and Dark Energy: The Hidden 95% of the Universe.  In this book, Clegg outlines "the biggest puzzle science has ever faced" -- the evidence for the substances that provide the majority of the gravitational force holding the nearby universe together, while simultaneously making the universe as a whole fly apart -- and which has (thus far) completely resisted all attempts to ascertain its nature.

Clegg also gives us some of the cutting-edge explanations physicists are now proposing, and the experiments that are being done to test them.  The science is sure to change quickly -- every week we seem to hear about new data providing information on the dark 95% of what's around us -- but if you want the most recently-crafted lens on the subject, this is it.

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

The smell of time passing

We once owned a very peculiar border collie named Doolin.  Although from what I've heard, saying "very peculiar" in the same breath as "border collie" is kind of redundant.  The breed has a reputation for being extremely intelligent, hyperactive, job-oriented, and more than a little neurotic, and Doolin fit the bill in all respects.

As far as the "intelligent" part, she's the dog who learned to open the slide bolts on our fence by watching us do it only two or three times.  I wouldn't have believed it unless I'd seen it with my own eyes.  She also took her job very seriously, and by "job" I mean "life."  She had a passion for catching frisbees, but I always got the impression that it wasn't because it was fun.  It was because the Russian judge had only given her a 9.4 on the previous catch and she was determined to improve her score.

There were ways in which her intelligence was almost eerie at times.  I was away from home one time and called Carol to say hi, and apparently Doolin looked at her with question marks in her eyes.  Carol said, "Doolin, it's Daddy!"  Doolin responded by becoming extremely excited and running around the house looking in all of the likely spots -- my office, the recliner, the workshop -- as well as some somewhat less likely places like under the bed.  When the search was unsuccessful, apparently she seemed extremely worried for the rest of the evening.

Not that this was all that different from her usual expression.

One thing that always puzzled us, though, was her ability to sense when we were about to get home.  Doolin would routinely go to the door and stand there on guard before Carol's car pulled into the driveway.  She did the same thing, I heard, when I was about to arrive.  In each case, there was no obvious cue that she could have relied on; we live on a fairly well-traveled stretch of rural highway and even if she heard our cars in the distance, I can't imagine they sound that different from any of the other hundreds of cars that pass by daily.  And my arrival time, especially, varied considerably from day to day, because of after-school commitments.  How, then, did she figure out we were about to get home -- or was it just dart-thrower's bias again, and we were noticing the times she got it right and ignoring all the times she didn't?

According to Alexandra Horowitz, a professor of psychology at Barnard University, there's actually something to this observation.  There are hundreds of anecdotal accounts of the same kind of behavior, enough that (although there hasn't been much in the way of a systematic study) there's almost certainly a reason behind it other than chance.  Horowitz considered the well-documented ability of dogs to follow a scent trail the right direction by sensing where the signal was weakest -- presumably the oldest part of the trail -- and heading toward where it was stronger.  The difference in intensity is minuscule, especially given that to go the right direction the dog can't directly compare the scent right here to the scent a half a kilometer away, but has to compare the scent here to the scent a couple of meters away.

What Horowitz wondered is if dogs are using scent intensity as a kind of clock -- the diminishment of a person's scent signal after they leave the house gives the dog a way of knowing how much time has elapsed.  This makes more sense than any other explanation I've heard, which include (no lie) that dogs are psychic and are telepathically sensing your approach.  Biological clocks of all kinds are only now being investigated and understood, including how they are entrained -- how the internal state is aligned to external cues.  (The most obvious examples of entrainment are the alignment of our sleep cycle to light/dark fluctuations, and seasonal behaviors in other animals like hibernation and migration in response to cues like decreasing day length.)

So it's possible that dogs are entraining this bit of their behavior using their phenomenally sensitive noses.  It'll be interesting to see what Horowitz does with her hypothesis; it's certainly worth testing.  Now, I need to wrap this up because Guinness's biological clock just went off and told him it was time to play ball.  Of course, that happens about fifty times a day, so there may not be anything particularly surprising there.

***********************

This week's Skeptophilia book of the week is brand new; Brian Clegg's wonderful Dark Matter and Dark Energy: The Hidden 95% of the Universe.  In this book, Clegg outlines "the biggest puzzle science has ever faced" -- the evidence for the substances that provide the majority of the gravitational force holding the nearby universe together, while simultaneously making the universe as a whole fly apart -- and which has (thus far) completely resisted all attempts to ascertain its nature.

Clegg also gives us some of the cutting-edge explanations physicists are now proposing, and the experiments that are being done to test them.  The science is sure to change quickly -- every week we seem to hear about new data providing information on the dark 95% of what's around us -- but if you want the most recently-crafted lens on the subject, this is it.

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

Misremembering the truth

There are two distinct, but similar-sounding, cognitive biases that I've written about many times here at Skeptophilia because they are such tenacious barriers to rational thinking.

The first, confirmation bias, is our tendency to uncritically accept claims when they fit with our preconceived notions.  It's why a lot of conservative viewers of Fox News and liberal viewers of MSNBC sit there watching and nodding enthusiastically without ever stopping and saying, "... wait a moment."

The other, dart-thrower's bias, is more built-in.  It's our tendency to notice outliers (because of their obvious evolutionary significance as danger signals) and ignore, or at least underestimate, the ordinary as background noise.  The name comes from the thought experiment of being in a bar while there's a darts game going on across the room.  You'll tend to notice the game only when there's an unusual throw -- a bullseye, or perhaps impaling the bartender in the forehead -- and not even be aware of it otherwise.

Well, we thought dart-thrower's bias was more built into our cognitive processing system and confirmation bias more "on the surface" -- and the latter therefore more culpable, conscious, and/or controllable.  Now, it appears that confirmation bias might be just as hard-wired into our brains as dart-thrower's bias is.

A paper appeared this week in Human Communication Research, describing research conducted by a team led by Jason Coronel of Ohio State University.  In "Investigating the Generation and Spread of Numerical Misinformation: A Combined Eye Movement Monitoring and Social Transmission Approach," Coronel, along with Shannon Poulsen and Matthew D. Sweitzer, did a fascinating series of experiments that showed we not only tend to accept information that agrees with our previous beliefs without question, we honestly misremember information that disagrees -- and we misremember it in such a way that in our memories, it further confirms our beliefs!

The location of memories (from Memory and Intellectual Improvement Applied to Self-Education and Juvenile Instruction, by Orson Squire Fowler, 1850) [Image is in the Public Domain]

What Coronel and his team did was to present 110 volunteers with passages containing true numerical information on social issues (such as support for same-sex marriage and rates of illegal immigration).  In some cases, the passages agreed with what (according to polls) most people believe to be true, such as that the majority of Americans support same-sex marriage.  In other cases, the passages contained information that (while true) is widely thought to be untrue -- such as the fact that illegal immigration across the Mexican border has been dropping for years and is now at its lowest rates since the mid-1990s.

Across the board, people tended to recall the information that aligned with the conventional wisdom correctly, and the information that didn't incorrectly.  Further -- and what makes this experiment even more fascinating -- is that when people read the unexpected information, data that contradicted the general opinion, eye-tracking monitors recorded that they hesitated while reading, as if they recognized that something was strange.  In the immigration passage, for example, they read that the rate of immigration had decreased from 12.8 million in 2007 to 11.7 million in 2014, and the readers' eyes bounced back and forth between the two numbers as if their brains were saying, "Wait, am I reading that right?"

So they spent longer on the passage that conflicted with what most people think -- and still tended to remember it incorrectly.  In fact, the majority of people who did remember wrong got the numbers right -- 12.8 million and 11.7 million -- showing that they'd paid attention and didn't just scoff and gloss over it when they hit something they thought was incorrect.  But when questioned afterward, they remembered the numbers backwards, as if the passage had actually supported what they'd believed prior to the experiment!

If that's not bad enough, Coronel's team then ran a second experiment, where the test subjects read the passage, then had to repeat the gist to another person, who then passed it to another, and so on.  (Remember the elementary school game of "Telephone?")  Not only did the data get flipped -- usually in the first transfer -- subsequently, the difference between the two numbers got greater and greater (thus bolstering the false, but popular, opinion even more strongly).  In the case of the immigration statistics, the gap between 2007 and 2014 not only changed direction, but by the end of the game it had widened from 1.1 million to 4.7 million.

This gives you an idea what we're up against in trying to counter disinformation campaigns.  And it also illustrates that I was wrong in one of my preconceived notions; that people falling for confirmation bias are somehow guilty of locking themselves deliberately into an echo chamber.  Apparently, both dart-thrower's bias and confirmation bias are somehow built into the way we process information.  We become so certain we're right that our brain subconsciously rejects any evidence to the contrary.

Why our brains are built this way is a matter of conjecture.  I wonder if perhaps it might be our tribal heritage at work; that conforming to the norm, and therefore remaining a member of the tribe, has a greater survival value than being the maverick who sticks to his/her guns about a true but unpopular belief.  That's pure speculation, of course.  But what it illustrates is that once again, our very brains are working against us in fighting Fake News -- which these days is positively frightening, given how many powerful individuals and groups are, in a cold and calculated fashion, disseminating false information in an attempt to mislead us, frighten us, or anger us, and so maintain their positions of power.

***********************

This week's Skeptophilia book of the week is brand new; Brian Clegg's wonderful Dark Matter and Dark Energy: The Hidden 95% of the Universe.  In this book, Clegg outlines "the biggest puzzle science has ever faced" -- the evidence for the substances that provide the majority of the gravitational force holding the nearby universe together, while simultaneously making the universe as a whole fly apart -- and which has (thus far) completely resisted all attempts to ascertain its nature.

Clegg also gives us some of the cutting-edge explanations physicists are now proposing, and the experiments that are being done to test them.  The science is sure to change quickly -- every week we seem to hear about new data providing information on the dark 95% of what's around us -- but if you want the most recently-crafted lens on the subject, this is it.

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

The fluid Earth

I've always had a fascination for maps, and when I was a kid spent many happy hours perusing a huge old world atlas my parents owned.

I remember how impossibly exotic a lot of those places seemed.  Some of them, too, seemed awfully oddly-shaped.  I remember being struck, for example, by the peculiar contour of the island of Celebes (now known as Sulawesi):

Map from The Birds of Celebes and the Neighouring Islands (1898) [Image is in the Public Domain]

What on earth gave the place its strange shape?  I was years away from finding out about plate tectonics, seafloor spreading, and continental drift -- this would have been 1968 or so, and the seminal paper by Fred Vine and Drummond Matthews confirming the truth of plate tectonics had only been published five years earlier, so the idea had yet to make its way into elementary school science classes.

The first inkling I had that the current map of the world was only the latest of a myriad configurations that Earth's land masses had taken was when I found out about marine fossils on the top of Mount Everest and tropical fossils in Antarctica in a book I had on prehistoric life.  Everything was shifting around, apparently, in some mysterious fashion, and the familiar maps from my parents' atlas would have been completely incorrect in the past.  For example, India broke off from what is now Madagascar, sliding across the ocean on its piece of plate, and rammed into Asia only fifty or so million years ago -- which may seem like a long time, but at that point the dinosaurs had already been extinct for fifteen million years (as I always feel obliged to add, except for birds).

Still, I didn't know much in the way of details.  When I took two geology courses in graduate school, however, I hit the idea head-on, including the now-familiar idea of Pangaea -- that there was a time when all of the continents were joined into one enormous land mass.  Even more mindblowing was the fact that this wasn't the only time this had happened -- the accretion and disintegration had occurred at least three or four times before, each time ending when rifts formed and forced the place apart.

The traces of these repeated hookups and breakups are still with us.  In fact, one was just announced in a paper recently in Geology, by a team led by Adam Nordsvan of Curtin University, in which evidence was uncovered that a piece of Australia -- the region of Georgetown in far northeastern Queensland -- was actually geologically related not to the rocks immediately adjacent to it, but to rocks in (of all places) Canada.

The Canadian (or Laurentian) Shield is one of the oldest relatively unaltered blocks of rock on the Earth, of Precambrian age -- on the order of three and a half billion years old -- so to a geologist, they're pretty distinct from the geology of the nearby Mount Isa formation, which is only half that old.  (I realize how ridiculous it is to use the word "only" to describe something 1.8 billion years old, but I'm trying to think like a geologist, here.)

The coolest thing is that the piece of Canada left behind in Australia wasn't from the most recent continental pile-up, which occurred on the order of three hundred million years ago, nor even the one before that.  The most likely time that Canada and Australia were joined together was three supercontinents ago, when all the Earth's land masses were fused around a billion years ago into a huge clump called Rodinia:

[Image is in the Public Domain]

So apparently when that rifted apart, around 750 million years ago, a chunk of Canada decided to split off and ended up (literally) on the other side of the world.

The whole thing is pretty cool.  I'm still fascinated by maps in general, and thinking about what the world was like when Antarctica was in the tropics of the Northern Hemisphere and the equator cut across what is now Labrador will never fail to spark my imagination.  Add to that the bizarre thought (to me, at least) that at that point, all living things were confined to the oceans -- there was not a bug, not a worm, not so much as a sprig of moss anywhere on land, the whole place was completely devoid of life -- well, it brings to mind the line from Contact about a universe empty of all life except for us being an "awful waste of space."

Fortunately for us, though, at that point the conquest of dry land was right around the corner.

"Only" three hundred million years later.

I'll end with the prescient lines from Alfred, Lord Tennyson, penned in 1849, long before continental drift was even considered:

There rolls the deep where grew the tree.
O Earth, what changes hast thou seen?
There where the long road roars has been
The stillness of the central sea;
The hills are shadows, and they flow
From form to form, and nothing stands,
They melt like mists, the solid lands,
Like clouds, they shape themselves and go.

***********************

This week's Skeptophilia book of the week is brand new; Brian Clegg's wonderful Dark Matter and Dark Energy: The Hidden 95% of the Universe.  In this book, Clegg outlines "the biggest puzzle science has ever faced" -- the evidence for the substances that provide the majority of the gravitational force holding the nearby universe together, while simultaneously making the universe as a whole fly apart -- and which has (thus far) completely resisted all attempts to ascertain its nature.

Clegg also gives us some of the cutting-edge explanations physicists are now proposing, and the experiments that are being done to test them.  The science is sure to change quickly -- every week we seem to hear about new data providing information on the dark 95% of what's around us -- but if you want the most recently-crafted lens on the subject, this is it.

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