Mathematical stumbles

In the first part of my teaching career, I taught mainly physics and math, before switching to biology (which I then taught for the rest of my 32 years).  During my time as a physics and math teacher, I was fascinated by the number of students who didn't seem to be able to think numerically.  Some of them were quite skilled at equation manipulation, and so got good grades on quizzes.  The trouble started when they punched something into their calculator wrong, and got an answer that was wildly off -- and then didn't recognize that anything was amiss.

Probably the most extreme example of this was a girl in my physics class.  While we were studying electrostatics, there was a problem set up that was intended to lead you in the end to a value for the mass of an electron.  Well, she entered the numbers wrong, or divided when she was supposed to multiply, or some other simplistic careless error -- and got an answer of 86 kilograms.

She called me over, because when she checked her answer against the accepted value, it wasn't the same.  (Really not the same.  The mass of an electron is about 9 x 10^-31 kilograms -- a decimal point, followed by thirty zeroes, ending with a nine.)

"I must have done something wrong," she said.

I laughed and said, "Yeah, that's kind of heavy for an electron."

She gave me a baffled look and said, "It is?"

I thought she was kidding, but it became obvious quickly that she wasn't.  She knew 86 kilograms wasn't the number in the reference tables, but she honestly had no idea how far off she was.

"86 kilograms is almost two hundred pounds," I said.

She went, "Oh."

I saw this kind of thing over and over, and the problem became worse when you threw scientific notation into the mix, which I suspect was part of the problem with my student.  It was all too common for students to believe that whatever came out of the calculator must be right -- many of them seemed to have no ability to give an order-of-magnitude check of their answers to see if they even made sense given the parameters of the problem they were trying to solve.

[Image is in the Public Domain]

It's easy for those of us who are mathematically adept to be feeling a little smug right now.  But what is interesting is that if you change the context of the question, all of us start having similar troubles -- even expert mathematicians.

A group of psychologists at the Université de Genève set up two different sorts of (very simple) math problems, one of which requires you to think in sets, the other in linear axes.  Here's an example of each:

• Set thinking:  Jim has fourteen pieces of fruit in his shopping basket, a combination of apples and pears.  John has two fewer pears than Jim, but the same number of apples.  How many total pieces of fruit does John have?
• Axes thinking:  When Jane stands on a tall ladder, she can reach a spot fourteen feet high on the side of a house.  Jane is the same height as her twin sister Jill.  If Jill stood on the same ladder, but on a step two feet lower down, how high could she reach?

Both of these problems have the same parameters.  There are pieces of information missing (in the first, the number each of apples and pears Jim has; in the second, Jane's height and the height of the step she's standing on).  In each case, though, the missing information is unnecessary for solving the problem, and in each the solution method is (the same) simple subtraction -- 14 - 2 = 12.

What is extraordinary is that when asked to solve the problems, with an option to answer "no solution because there is insufficient information," people solved the axes problems correctly 82% of the time, and the sets problems only 47% of the time!

Even more surprising were the results when the same problems were given to expert mathematicians.  They got 95% of the axis problems correct -- but only 76% of the sets problems!

I found these results astonishing -- almost a quarter of the mathematicians thought that the information in the "apples and pears" problem above, and others like it, was insufficient to answer the question.

"We see that the way a mathematical problem is formulated has a real impact on performance, including that of experts, and it follows that we can't reason in a totally abstract manner," said Emmanuel Sander, one of the researchers in the study.

"One out of four times, the experts thought there was no solution to the problem even though it was of primary school level," said Hippolyte Gros, another of the authors of the paper, which appeared in the journal Psychonomic Bulletin and Review.  "And we even showed that the participants who found the solution to the set problems were still influenced by their set-based outlook, because they were slower to solve these problems than the axis problems...  We have to detach ourselves from our non-mathematical intuition by working with students in non-intuitive contexts."

What this shows is that the inability to think numerically -- what researchers term innumeracy -- isn't as simple as just a stumbling block in quantitative understanding.  Presumably expert mathematicians aren't innumerate (one would hope not, anyway), but there's still something going awry with their cognitive processing in the realm of sets that does not cause problems with their thinking about linear axes.  So it's not a mental math issue -- the mental math necessary for both problems is identical -- it's that somehow, the brain doesn't categorize the two different contexts as having an underlying similarity.

Which I find fascinating.  I'd love to have the same experiment run while the participants are hooked to an fMRI machine, and see if the regions of the brain activated in sets problems are different from the parts in axes problems.  I'd bet cold hard cash they are.

However, it still probably wouldn't answer what was amiss with the student who had the 86 kilogram electron.

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This week's Skeptophilia book of the week is both intriguing and sobering: Eric Cline's 1177 B.C.: The Year Civilization Collapsed.

The year in the title is the peak of a period of instability and warfare that effectively ended the Bronze Age.  In the end, eight of the major civilizations that had pretty much run Eastern Europe, North Africa, and the Middle East -- the Canaanites, Cypriots, Assyrians, Egyptians, Babylonians, Minoans, Myceneans, and Hittites -- all collapsed more or less simultaneously.

Cline attributes this to a perfect storm of bad conditions, including famine, drought, plague, conflict within the ruling clans and between nations and their neighbors, and a determination by the people in charge to keep doing things the way they'd always done them despite the changing circumstances.  The result: a period of chaos and strife that destroyed all eight civilizations.  The survivors, in the decades following, rebuilt new nation-states from the ruins of the previous ones, but the old order was gone forever.

It's impossible not to compare the events Cline describes with what is going on in the modern world -- making me think more than once while reading this book that it was half history, half cautionary tale.  There is no reason to believe that sort of collapse couldn't happen again.

After all, the ruling class of all eight ancient civilizations also thought they were invulnerable.

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

A twist in the fabric

I hope y'all will indulge me one more astronomical post, because just this week in the journal Science there was a very cool paper about an observational verification of the phenomenon of frame-dragging.

The whole thing depends on the the concept of "the fabric of space-time," something that got ripped so often on Star Trek that you'd swear the universe was made of cheap pantyhose.  To be fair, the idea isn't easy to wrap your brain around, something that becomes obvious when you hear some laypeople talking about the Big Bang.

I mean, I try to be tolerant, but if I hear one more person say, "It's a stupid idea -- that nothing exploded and became everything," I swear, I'm going to hurl a heavy object at 'em.

The problem hinges on trying to draw an analogy between the Big Bang (or in general, the expansion of the Universe) with a conventional explosion, where something blows up and spreads out into space that was already there.  With the Big Bang, it was space itself that was stretching -- if the idea of cosmic inflation turns out to be correct, at first it was at a rate that I can't even begin to comprehend -- so the matter in the Universe moved, and is still moving, not because something was physically pushing on it (as in the explosion of a stick of dynamite), but because the space it was embedded in was expanding.

(For what it's worth -- no, at this point we don't understand why this happened, what initiated it, or why the rate changed so suddenly after the "inflationary era" was over.  There is a lot still to figure out about this.  But one thing that's nearly certain is that it did happen, and the evidence still left behind of the Big Bang is incontrovertible.)

In any case, it's useful to change the comparison.  The Big Bang, and the expansion that followed, is much less like a conventional explosion than it is like blowing up a balloon.  Astronomer Edwin Hubble realized this when he first observed red shift, and found that everywhere he looked in the universe, objects seemed to be flying away from us -- the farther away, the faster they were moving.  It looked very much like we were the center of the Universe, the middle of the explosion, as if you were at the very point where a bomb exploded and were watching the bits and pieces rush away from you.

The truth, Hubble realized, was more subtle, but also way more interesting.  The fabric of space itself was stretching.  Picture a deflated balloon covered with dots.  You're a tiny person standing on one of the dots.  The balloon inflates -- and all the other dots appear to be rushing away from you.  But the weird thing is that it doesn't matter which dot you're standing on.  You could be on any dot, and still all the others would appear to be moving away, because the surface itself is expanding.  So an alien in a distant galaxy would also think everything was moving away from him, and he and Hubble would both be right.

There is no center of the Universe.  Or everywhere is the center.

Which amounts to the same thing.

So it's much more accurate, if you're trying to picture the whole thing, to think of space as being some kind of "stuff" capable of being deformed or stretched.

Which leads us to this week's mind-blowing discovery in astronomy.

One of the stranger predictions of the General Theory of Relativity -- and there's a lot of competition in that regard -- is that a massive spinning object would drag space-time along with it, twisting it out of shape in a phenomenon called Lense-Thirring frame dragging after the Austrian physicists who predicted it based on Einstein's theories, Josef Lense and Hans Thirring.  The problem is, like most of the phenomena associated with Relativity, the Lense-Thirring effect would only be observed in extreme conditions -- in this case a very high-mass object spinning really fast.

To give you an idea of what kind of extremes I'm talking about, here: with the Earth's mass and spin, the Lense-Thirring effect would cause an angular shift of about one degree every 100,000 years.

Not exactly something that jumps out at you.

[Image licensed under the Creative Commons ALMA (ESO/NAOJ/NRAO)/H. Kim et al., Celestial spiral with a twist, CC BY 4.0]

Now some scientists led by Vivek Venkatraman Krishnan of the Max Planck Institute have found a remarkable pair of stellar remnants that provide the perfect laboratory for observing frame-dragging -- a white dwarf/pulsar pair that go by the euphonious name PSR J1141-6545.  This is an ideal pairing to study because both the white dwarf and the pulsar are spinning, the white dwarf about once a minute and the pulsar 2.5 times per second.  Because the pulsar emits a lighthouse-like beam of electromagnetic radiation, this rotation makes it flicker on and off, and Conservation of Angular Momentum makes the flicker rate extremely constant -- in fact, the rotational period has been calculated to an accuracy of ten decimal places.

But the whirling of its companion star results in frame-dragging, so the pulsar's beam has developed a tilt as it got pulled through twisted space-time.  (Imagine a flexible object bending as it's dragged through water, and you have an idea of how to picture this.)  And careful observation of the pulsar's wobble has shown that the amount of tilt...

... is exactly what is predicted from the General Theory of Relativity.

So Einstein wins again.  Pretty impressive for a guy who once said to a friend struggling in a math class, "Do not worry too much about your difficulties in mathematics.  I can assure you that mine are still greater."

So that's our mindblowing science of the day.  Spinning stars, twisting space-time, and tilted pulsars.  I don't know how anyone can read about this stuff and not be both fascinated at how weird our universe is, and astonished that we've progressed to the point where we can understand at least a bit of it.  Here, several hundred quadrillion kilometers away, we've detected minuscule tilts in a whirling stellar remnant, and used it to support a theory that describes how matter and energy work throughout the Universe.

If that's not an impressive accomplishment, I don't know what is.

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The brilliant, iconoclastic physicist Richard Feynman was a larger-than-life character -- an intuitive and deep-thinking scientist, a prankster with an adolescent sense of humor, a world traveler, a wild-child with a reputation for womanizing.  His contributions to physics are too many to list, and he also made a name for himself as a suspect in the 1950s "Red Scare" despite his work the previous decade on the Manhattan Project.  In 1986 -- two years before his death at the age of 69 -- he was still shaking the world, demonstrating to the inquiry into the Challenger disaster that the whole thing could have happened because of an o-ring that shattered from cold winter temperatures.

James Gleick's Genius: The Life and Science of Richard Feynman gives a deep look at the man and the scientist, neither glossing over his faults nor denying his brilliance.  It's an excellent companion to Feynman's own autobiographical books Surely You're Joking, Mr. Feynman! and What Do You Care What Other People Think?  It's a wonderful retrospective of a fascinating person -- someone who truly lived his own words, "Nobody ever figures out what life is all about, and it doesn't matter.  Explore the world.  Nearly everything is really interesting if you go into it deeply enough."

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

Hotspot

Today's topic in Skeptophilia isn't controversial so much as it is amazing.  And shows us once again what a weird, endlessly fascinating universe we live in.

First, though, a bit of a science lesson.

A great many processes in the natural world happen because of the Second Law of Thermodynamics.  The Second Law can be framed in a variety of ways, two of which are: (1) heat always tends to flow from a hotter object to a colder one; and (2) in a closed system, entropy -- disorder -- always increases.  (Why those are two ways of representing the same underlying physical law is subtle, and beyond the scope of this post.)

In any case, the Second Law is the driver behind weather.  Just about all weather happens because of heat energy redistribution -- the Sun warms the ground, which heats the air.  Hot air tends to rise, so it does, drawing in air from the sides and creating a low pressure center (and wind).  As the warm air rises, it cools (heat flowing away from the warmer blob of air), making water vapor condense -- which is why low pressure tends to mean precipitation.  Condensation releases heat energy, which also wants to flow toward where it's cooler, cooling the blob of air (which is also cooling because it's rising and expanding).  When the air cools enough, it sinks, forming a high pressure center -- and on and on.  (Circular air movement of this type -- what are called convection cells -- can be local or global in reach.  Honestly, a hurricane is just a giant low-pressure convector.  A heat pump, in essence.  Just a fast and powerful one.)

Okay, so that's the general idea, and to any physicists who read this, I'm sorry for the oversimplifications (but if I've made any outright errors, let me know so I can fix them; there's enough nonsense out there based in misunderstandings of the Second Law that the last thing I want is to add to it).  Any time you have uneven heating, there's going to be a flow of heat energy from one place to the other, whether through convection, conduction, or radiation.

But if you think we get some violent effects from this process here on Earth, wait till you hear about KELT-9b.

KELT-9b is an exoplanet about 670 light years from Earth.  But it has some characteristics that would put it at the top of the list of "weirdest planets ever discovered."  Here are a few:

• It's three times the mass of Jupiter, the largest planet in our Solar System.
• It's moving at a fantastic speed, orbiting its star in only a day and a half.
• It's tidally locked -- the same side of the planet is always facing the star, meaning there's a permanently light side and a permanently dark side.
• It's the hottest exoplanet yet discovered -- the light side has a mean temperature of 4,300 C, which is hotter than some stars.

So the conditions on this planet are pretty extreme.  But as I found out in a paper by Megan Mansfield of the University of Chicago et al. that appeared in this week's Astrophysical Journal Letters, even knowing all that didn't stop it from harboring a few more surprises.

Artist's conception of KELT-9b [Image is in the Public Domain courtesy of NASA/JPL]

Tidally-locked planets are likely to have some of the most extraordinary weather in the universe, again because of effects of the Second Law.  Here on Earth, with a planet that rotates once a day, the land surface has an opportunity to heat up and cool down regularly, giving the heat redistribution effects of the Second Law less to work with.  On KELT-9b, though, the same side of the planet gets cooked constantly, so not only is it really freakin' hot, there's way more of a temperature differential between the light side and the dark side than you'd ever get in our Solar System (even Mercury doesn't have that great a difference).

So there must be a phenomenal amount of convection taking place, with the atmosphere on the light side convecting toward the dark side like no hurricane we've ever seen.  But that's where Mansfield et al. realized something was amiss.  Because to account for the temperature distribution they were seeing on KELT-9b, there would have to be wind...

... moving at 150,000 miles per hour.

That seemed physically impossible, so there had to be some other process moving heat around besides simple convection.  The researchers found out what it is -- the heat energy on the light side is sufficient to tear apart hydrogen molecules.

At Earth temperatures, hydrogen exists as a diatomic molecule (H2).  But at KELT-9b's temperatures, the energy tears the molecules into monoatomic hydrogen, storing that as potential energy that is then rereleased when the atoms come back together on the dark side.  So once again we're talking the Second Law -- heat flowing toward the cooler object -- but the carrier of that heat energy isn't just warm air or warm water, but molecules that have been physically torn to shreds.

So, fascinating as it is, KELT-9b would not be the place for Captain Picard to take his away team.  But observed from a distance, it must be spectacular -- glowing blue-white from its own heat, whirling around its host star so fast its year is one and a half of our days, one side in perpetual darkness.  All of which goes to show how prescient William Shakespeare was when he wrote, "There are more things in heaven and Earth, Horatio, than are dreamt of in your philosophy."

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

The brilliant, iconoclastic physicist Richard Feynman was a larger-than-life character -- an intuitive and deep-thinking scientist, a prankster with an adolescent sense of humor, a world traveler, a wild-child with a reputation for womanizing.  His contributions to physics are too many to list, and he also made a name for himself as a suspect in the 1950s "Red Scare" despite his work the previous decade on the Manhattan Project.  In 1986 -- two years before his death at the age of 69 -- he was still shaking the world, demonstrating to the inquiry into the Challenger disaster that the whole thing could have happened because of an o-ring that shattered from cold winter temperatures.

James Gleick's Genius: The Life and Science of Richard Feynman gives a deep look at the man and the scientist, neither glossing over his faults nor denying his brilliance.  It's an excellent companion to Feynman's own autobiographical books Surely You're Joking, Mr. Feynman! and What Do You Care What Other People Think?  It's a wonderful retrospective of a fascinating person -- someone who truly lived his own words, "Nobody ever figures out what life is all about, and it doesn't matter.  Explore the world.  Nearly everything is really interesting if you go into it deeply enough."

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

An epidemic of lunacy

Humans are odd creatures sometimes.

We have a regrettable tendency to abandon reason entirely when we're confronted with scary circumstances.  I suppose it's understandable enough; we're emotional as well as logical, and when we're frightened the emotional parts of our brain tend to swamp the more rational bits.

Still, it'd be nice if we could control that tendency, because it would help to reduce our likelihood of falling for weird counterfactual explanations at the times that it's the most critical for us to keep our  heads screwed on straight.

Take, for example, the most recent Scary Circumstance, namely, the outbreak of Wuhan coronavirus that so far has killed just over a hundred people, sickened thousands, and (by some estimates) left over a hundred thousand people at risk of exposure.

Coronaviruses [Image is in the Public Domain, courtesy of the CDC]

Worrisome stuff, isn't it?  The potential for a pandemic is there, and the unknowns about the virus still outnumber the knows -- the rate at which it's passed on (what the epidemiologists refer to as "R0"), whether it's mutating as it spreads, what the mortality rate is, whether it's contagious while an individual is still asymptomatic.  But as I alluded to earlier, "frightening unknown virus" does not equate to "I think I'll make bizarre shit up."

Let's start with something I've now seen four times on social media, although I couldn't find a good link to the origin of the claim.  This particular flavor of nonsense is that the coronavirus outbreak is particularly dangerous to a specific subset of humanity...

... people who have been vaccinated for other diseases.

It will come as no surprise that the people who are spreading this foolishness are the anti-vaxxers.  How exactly a vaccine for (say) mumps would make you more likely to contract coronavirus they never explain.  The reason for that, of course, is that there is no explanation, because the claim itself is idiotic.  The anti-vaxxers are simply looking for another horrible thing to blame on vaccines, and the Big Bad Guys pushing vaccination -- doctors and "Big Pharma."  And since there is no actual evidence vaccines are dangerous, and ample evidence they reduce your risk of a number of deadly diseases to near zero, if you're going to claim otherwise you pretty much have to spin your argument from whole cloth.

That feeling when you're so ignorant about vaccines you end up reinventing them by mistake.  [Screencap from Twitter]

Then, there's the even more insidious approach of the insane conspiracy theory group QAnon, who have a two-part claim: (1) that Bill Gates patented the Wuhan coronavirus in 2015 and is using it to kill off the weak in some sort of bizarre eugenics experiment; and (2) that all you have to do to cure a coronavirus infection is to drink bleach.

As far as the first part, I don't know what to say except "are you fucking kidding me right now?"  The second part, though, has been around for a while -- the bleach solution ("Miracle Mineral Solution," which contains chlorine dioxide, a highly toxic compound) has been touted as a cure-all for all sorts of viral and bacterial infections.  And the claim is correct in a sense; if you have a coronavirus infection and you drink Miracle Mineral Solution, you won't be sick any more.

You'll be dead.

Lastly, from the "How Do People This Stupid Exist?" department, we have the folks who apparently think that coronavirus has something to do with Corona beer, other than the fact that "corona" appears in both names.

Corona, I hasten to point out (probably unnecessarily), is the Latin word for "crown."  The virus got that name because it's covered with spiky projections that look a little bit crown-like; the beer was given that name because its manufacturers wanted people to think it was the King of Beers (another incorrect claim, as the King of Beers is clearly Guinness).  But the similarity between the names has evidently led some people to think that there is more to it than that, and Google searches for "beer virus" have gone through the roof.

What exactly people think the connection is, I have no idea.  My hopeful side tells me that maybe people are just wanting to find out if anyone really is silly enough to think that the beer contains the virus.  But my gut tells me that it's more likely there really are people who believe the beer is transmitting the virus, or the beer cures the virus, or possibly both at the same time.

Who the hell knows?

Anyhow -- until such time as a coronavirus vaccine is developed, the best way to avoid catching or passing on infection is to do what you (hopefully) are doing already during flu season -- wash your hands frequently, cover your mouth when you cough or sneeze, and if you're sick yourself, stay home.  Other than that, try to resist the temptation to let your emotions carry you away.  Epidemics are bad enough without loopy speculation getting in the way.

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The brilliant, iconoclastic physicist Richard Feynman was a larger-than-life character -- an intuitive and deep-thinking scientist, a prankster with an adolescent sense of humor, a world traveler, a wild-child with a reputation for womanizing.  His contributions to physics are too many to list, and he also made a name for himself as a suspect in the 1950s "Red Scare" despite his work the previous decade on the Manhattan Project.  In 1986 -- two years before his death at the age of 69 -- he was still shaking the world, demonstrating to the inquiry into the Challenger disaster that the whole thing could have happened because of an o-ring that shattered from cold winter temperatures.

James Gleick's Genius: The Life and Science of Richard Feynman gives a deep look at the man and the scientist, neither glossing over his faults nor denying his brilliance.  It's an excellent companion to Feynman's own autobiographical books Surely You're Joking, Mr. Feynman! and What Do You Care What Other People Think?  It's a wonderful retrospective of a fascinating person -- someone who truly lived his own words, "Nobody ever figures out what life is all about, and it doesn't matter.  Explore the world.  Nearly everything is really interesting if you go into it deeply enough."

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

Sparkling camouflage

Natural selection is such an amazing driver of diversity.  As Richard Dawkins showed so brilliantly in his tour-de-force The Blind Watchmaker, all you have to have is an imperfect replicator and a selecting agent, and you can end up with almost any result.

The only requirement is that the change has to enhance survival and/or reproduction now.  Evolution is not forward-looking, heading in the direction of whatever would be a cool idea.  (It'd be nice if it were; I've wanted wings for ages.  Big, feathery falcon wings from my shoulders.  It'd make wearing a shirt impossible, but let's face it, I hate wearing shirts anyway so that's really not much of a sacrifice.)

Anyhow, the trick sometimes is figuring out what the benefit is, because it's not always obvious.  The extravagant tail of the peacock is clearly an attractant for females, although at this point the male peacocks may have maxed out -- reached the point where the tail's advantage of attracting females is counterbalanced by the disadvantage of being so cumbersome that it makes it harder to escape predators.  When two competing selecting agents hit that balance point, the species -- with respect to that trait, at least -- stops evolving.

A good bunch of the wild colorations you find in nature have to do with sex.  Not only attracting mates in animals, but colorful flowers attracting a specific pollinator -- because pollination is (more or less) plant sex.  But not all; the stripes of the Bengal tiger are thought to break up its silhouette in the dappled sunlight of its forest home, making it less visible to prey.  The bright colors of the dart-poison frogs are warning colorations, advertising the fact that they're highly poisonous and that predators shouldn't even think about it if they know what's good for them.  A recent study concluded that one advantage of stripes in the zebra is that it confuses biting flies, including the dangerous tsetse fly (carrier of African sleeping sickness) -- horses that were draped with striped cloth (mimicking the zebra's patterns) were far less susceptible to horsefly bites.  It's probable that the stripes also confuse predators such as lions, which frequently try to target one animal in a fleeing herd and separate it from the rest, a task that's difficult if the stripes make it hard to tell where one zebra begins and the other ends.  So zebra stripes may be a twofer.

Sometimes, though, the reason for a bright coloration isn't obvious.  In the summer here in upstate New York we often see brilliant little tiger beetles, named not for stripes (most of them don't have 'em) but for their role as a voracious predator of other insects.  The ones we have here are a glistening emerald green, which I always figured camouflaged them on plant leaves -- but there are ones that are an iridescent blue, and one species is green and blue with orange spots.

Hard to call that camouflage.

[Image licensed under the Creative Commons Ryan Hodnett, Six-spotted Tiger Beetle (Cicindela sexguttata) - Mississauga, Ontario 01, CC BY-SA 4.0]

Turns out that even the non-green ones might be using their sparkling colors as camouflage, however implausible that sounds.  A study that appeared this week in Current Biology, led by Karin Kjernsmo of the University of Bristol, concluded that the iridescence itself confuses predators, as much as it seems like it would attract attention.

Kjernsmo was studying the aptly-named Asian jewel beetles, which like our North American tiger beetles come in a wide range of glittering colors.  She took the wing cases of jewel beetles, both the iridescent and the matte species, and baited them with mealworms to see if birds had a preference.  85% of the targets with matte wings (of various colors) were picked off by birds, while only 60% of the iridescent ones were.

"It may not sound like much," Kjernsmo said, "but just imagine what a difference this would make over evolutionary time."

Her next question, though, was why.  This is much harder to determine, mostly because you can't ask a bird why it picked a particular insect for lunch.  (Well, you can ask.)  So what she did was a simple but suggestive experiment using human subjects -- she stuck various-colored wing cases to leaves at eye level on a forest trail, and had thirty-six human subjects walk the trail and see how many they could find.  They found 80% of the matte ones -- and only 17% of the iridescent ones!

It's a surprising result.  It may be that the shifting, sparkling surface of an iridescent insect confounds the ability of your visual cortex to make sense of what it's seeing by rendering it more difficult to perceive the edges, and therefore the shape, of what you're looking at.  The result: you can see the colors, but you don't recognize it as a beetle.  It's a plausible guess, but it will take more research to find out if it's the correct one, and if the reason the humans couldn't see iridescent wings is the same as why birds didn't eat them.

But once again, we're left with a slight difference in selection by a predator leading to what Darwin called "endless forms most beautiful and most wonderful."  The natural world is deeply fascinating, and is even more wonderful when you not only can appreciate its beauty -- but understand where that beauty may have come from.

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The brilliant, iconoclastic physicist Richard Feynman was a larger-than-life character -- an intuitive and deep-thinking scientist, a prankster with an adolescent sense of humor, a world traveler, a wild-child with a reputation for womanizing.  His contributions to physics are too many to list, and he also made a name for himself as a suspect in the 1950s "Red Scare" despite his work the previous decade on the Manhattan Project.  In 1986 -- two years before his death at the age of 69 -- he was still shaking the world, demonstrating to the inquiry into the Challenger disaster that the whole thing could have happened because of an o-ring that shattered from cold winter temperatures.

James Gleick's Genius: The Life and Science of Richard Feynman gives a deep look at the man and the scientist, neither glossing over his faults nor denying his brilliance.  It's an excellent companion to Feynman's own autobiographical books Surely You're Joking, Mr. Feynman! and What Do You Care What Other People Think?  It's a wonderful retrospective of a fascinating person -- someone who truly lived his own words, "Nobody ever figures out what life is all about, and it doesn't matter.  Explore the world.  Nearly everything is really interesting if you go into it deeply enough."

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

Hunters in the skies

Despite what you might have gathered from movies like Jurassic Park, we know very little about the behavior and appearance of prehistoric animals.

The exceptions stand out because they're so rare.  We know that Cretaceous-era hadrosaur Maiasaura nested in colonies -- because paleontologists have found entire family groups fossilized in place, with nests, eggs, and young all together at the same time.  The large ornithopod Iguanodon seems to have traveled in herds, given the 1878 discovery of 31 individuals that all died more or less simultaneously in what is now Belgium.  The Cretaceous parkosaurid Oryctodromeus apparently spent a lot of time in underground burrows judging from remains found in Montana and Idaho.

And a handful of others.  Surprisingly, one of the most iconic dinosaurs from Jurassic Park -- the Velociraptor -- has never been conclusively shown to be a pack hunter (although it may have been), and almost certainly wasn't intelligent enough to figure out how to open the latch on a walk-in freezer.

So she may not have been such a Clever Girl after all.

As far as appearance, that can be even dicier.  From complete skeletons, scientists can use the position of muscle attachment points to make a good approximation at body contour, but there are a lot of structures without bones that wouldn't fossilize at all.  Consider, for example, that a fossilized elephant skeleton would show very little evidence of a trunk -- so future paleontologists probably wouldn't know it had one, and their reconstruction would look pretty different from reality.  When feathers or hair are preserved -- itself an unlikely occurrence -- scientists can guess at color and patterns from traces of pigments left behind, as with the feathered pterosaur whose tail feathers showed clear evidence of banding.

Other than that, it's pretty much all speculation based on analogy to modern species.  So it's a fair bet that if we time-traveled back to a hundred million years ago, we'd have a hell of a lot of surprises when we saw how those critters actually behaved, what they looked like, and what they sounded like.

This is why when there's a fossil that gives us a clue about behavior, it's pretty special.  Like the one described in a paper in Scientific Reports yesterday -- a fossilized squid that had a tooth from a pterosaur embedded in it.

The 150-million-year-old fossil, found in Germany, is of a thirty-centimeter-long individual of the prehistoric squid genus Plesioteuthis, but when the scientists looked carefully at it they found something extraordinary -- there was a long tooth fragment in the mantle, which after analysis they concluded came from the pterosaur Rhamphorhynchus.  I've always loved the pterosaurs -- they're far and away my favorite prehistoric animals (yes, I have favorite prehistoric animals.  Doesn't everyone?).  They vary in size from little Sordes pilosus, with a wingspan of only 0.8 meters or so, up to the mind-bogglingly huge Quetzalcoatlus, which was as long tip-to-tail as a giraffe and had a wingspan of twelve meters -- as large as a small airplane.  (Imagine what you'd do if one of those glided overhead while you were out picnicking.)

Rhamphorhynchus was on the small end of things, with a 1.8 meter wingspan.  It was a pretty cool-looking creature (I mean, as far as we can tell) -- with a long tail ending in a diamond-shaped rudder.

An amazingly well-preserved fossil of Rhamphorhynchus from Germany [Image licensed under the Creative Commons Mike Beauregard from Nunavut, Canada, Rhamphorhynchus gemmingi pterosaur, CC BY 2.0]

So the new fossil find gives us some interesting evidence for this beast's feeding behavior.  What it looks like is that it probably flew low over bodies of water, similar to what the remarkable birds called Black Skimmers do today, grabbing prey that ventured too near to the surface with their long, toothy beaks.  Only this time a Rhamphorhynchus lost its fight for dinner -- it might be that at thirty centimeters, the squid was too large or too heavy for it to pull out of the water -- and lost a tooth as well.  The squid went on to fight its battles for survival another day (as, probably, did the Rhamphorhynchus), only to end up as a fossil itself, still with the predator's tooth buried in its mantle.

This fascinating glimpse of how these hunters in the prehistoric skies found their prey is all the more cool for its rarity.  It's not often the remains of a long-deceased animal can give you hints about how it behaved when it was alive.  This lens into the past has allowed us to glimpse a diverse group that died out completely 66 million years ago -- flying dinosaurs that dominated the air of a long-lost world.

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

The brilliant, iconoclastic physicist Richard Feynman was a larger-than-life character -- an intuitive and deep-thinking scientist, a prankster with an adolescent sense of humor, a world traveler, a wild-child with a reputation for womanizing.  His contributions to physics are too many to list, and he also made a name for himself as a suspect in the 1950s "Red Scare" despite his work the previous decade on the Manhattan Project.  In 1986 -- two years before his death at the age of 69 -- he was still shaking the world, demonstrating to the inquiry into the Challenger disaster that the whole thing could have happened because of an o-ring that shattered from cold winter temperatures.

James Gleick's Genius: The Life and Science of Richard Feynman gives a deep look at the man and the scientist, neither glossing over his faults nor denying his brilliance.  It's an excellent companion to Feynman's own autobiographical books Surely You're Joking, Mr. Feynman! and What Do You Care What Other People Think?  It's a wonderful retrospective of a fascinating person -- someone who truly lived his own words, "Nobody ever figures out what life is all about, and it doesn't matter.  Explore the world.  Nearly everything is really interesting if you go into it deeply enough."

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

Jump scare preparation

When I was about twelve, I was lying on the sofa in my living room one evening watching a horror movie called Gargoyles.

From the perspective of a few more decades of living, I can say now that Gargoyles was a pretty derpy movie.  The general gist was that the people who put gargoyle statues on Gothic cathedrals were sculpting from life, and that all over the world there were caves occupied by the great-great-great-etc. grandchildren of those medieval monsters.  So of course there's the intrepid scientist character who is convinced that gargoyles exist but can't get his supervisors to believe him, but he goes and investigates them anyhow, and in the process hits one of them with his pickup truck.  (The gargoyles, not his supervisors.)

[Image licensed under the Creative Commons Florian Siebeck, Paris Gargoyle, CC BY-SA 3.0]

Well, the scientist is just thrilled by this development.  He thinks, "Wow, now I have proof!", loads the deceased gargoyle into his truck, and then stops at a motel for the night.  Then he does what you would do if you had never ever ever watched a horror movie in your life, namely: he decides that he can't leave a gargoyle corpse in the open bed of his pickup truck in the parking lot of a motel, so he drags it into the room with him.

He gets undressed for bed, turns out the lights, and -- of course -- it turns out the gargoyle isn't dead.  There's a soft, stealthy noise, and then a vaguely humanoid-shaped shadow rises, looming over the foot of the sleeping scientist's bed.

This was when my father, who was sitting in the recliner next to the couch, reached out and grabbed my shoulder and yelled, "THERE'S ONE NOW!"

After he peeled me off the ceiling with a spatula and my heart rate began to return to normal, I at least was thankful that I hadn't pissed my pants.  It was a close-run thing.

It's a wonder that I actually watch horror movies at all, because I am seriously suggestible.  When the movie The Sixth Sense first was released on DVD, my girlfriend (now wife) and I watched it at her house.  Then I had to make a forty-five minute drive, alone in my car at around midnight, then go (still alone) into my cold, dark, empty house.  I might actually have jumped into bed from four feet away so the evil little girl ghost wouldn't reach out from underneath and grab my ankle.  I also might have pulled the blankets up as high over me as I could without suffocating, following the time-tested rule that monsters' claws can't pierce a down comforter.

So yeah.  I might be a skeptic, but I am also a great big coward.

This was why I found some research that was published in the journal Neuroimage last week so fascinating.  It comes out of the University of Turku (Finland), where a team led by neuroscientist Lauri Nummenmaa had people watching movies like The Devil's Backbone and The Conjuring while hooked to an fMRI scanner.

They had participants (all of whom said they watched at least one horror movie every six months) rate the movies they watched for suspense and scariness, count the number of "jump scares," and evaluate their overall quality.  The scientists then looked at the fMRI results to see what parts of the brain were active when, and found some interesting patterns.

As the tension is increasing -- points where you're thinking, "Something scary is going to happen soon" -- the parts of the brain involved in visual and auditory processing ramp up activity.  Makes sense; if you were in a situation with real threats, and were worried about some imminent danger, you would begin to pay more attention to your surroundings, looking for cues to whether your fears were justified.  Then at the moment of jump scares, the parts of the brain involved in decision-making and fight-or-flight response spike in activity, as you make the split-second decision whether to run, fight the monster, or (most likely in my case) just have a stroke and drop dead on the spot.

Nummenmaa and his team found, however, that all through the movie, the sensory processing and rapid-response parts of the brain were in continuous cross-talk.  Apparently the brain is saying, "Okay, we're in a horror movie, so something terrifying is bound to happen sooner or later.  May as well prepare for it now."

What I still find fascinating, though, is why people actually like this sensation.  Even me.  I mean, my favorite Doctor Who episode -- the one that got me hooked on the series in the first place -- is the iconic episode "Blink," featuring the terrifying Weeping Angels, surely one of the scariest fictional monsters ever invented.

Maybe it's so when the movie's over, we can reassure ourselves that we might have problems in our lives, but at least we're not being disemboweled by a werewolf or abducted by aliens or whatnot.  I'm not sure if this is true for me, though.  Because long after the movie's over, I'm still convinced that whatever horrifying creature was rampaging through the story, it's still out there.

And it's looking for me.

So maybe I shouldn't watch scary movies.  It definitely takes a toll on me.  And that's even without my practical joker father scaring me out of five years of my life expectancy when the monster appears.

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

The brilliant, iconoclastic physicist Richard Feynman was a larger-than-life character -- an intuitive and deep-thinking scientist, a prankster with an adolescent sense of humor, a world traveler, a wild-child with a reputation for womanizing.  His contributions to physics are too many to list, and he also made a name for himself as a suspect in the 1950s "Red Scare" despite his work the previous decade on the Manhattan Project.  In 1986 -- two years before his death at the age of 69 -- he was still shaking the world, demonstrating to the inquiry into the Challenger disaster that the whole thing could have happened because of an o-ring that shattered from cold winter temperatures.

James Gleick's Genius: The Life and Science of Richard Feynman gives a deep look at the man and the scientist, neither glossing over his faults nor denying his brilliance.  It's an excellent companion to Feynman's own autobiographical books Surely You're Joking, Mr. Feynman! and What Do You Care What Other People Think?  It's a wonderful retrospective of a fascinating person -- someone who truly lived his own words, "Nobody ever figures out what life is all about, and it doesn't matter.  Explore the world.  Nearly everything is really interesting if you go into it deeply enough."

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