Dance of life

Dancing is ubiquitous amongst human societies.

Everywhere you go, every culture you look at, there is some form of rhythmic movement, usually to music.  (Sometimes the dancing creates its own music.)  I love to dance; I'm not saying I'm great at it, but starting out the day by putting on some tunes and moving my body just feels good.  And it's much more fun to do daily chores like cooking dinner with my music on, rockin' to the beat while I'm chopping the vegetables.

It's an interesting question why this is.  A shrewd guess is that a lot of it is about social cohesion.  You get a bunch of people together, all moving in the same way to the same rhythm, and it's a strong symbol of unity and common purpose.  

There's some biochemical support for this contention.  A series of studies a few years ago found that dancing releases four of the most important feel-good and bonding hormones -- dopamine, oxytocin, serotonin, and endorphin.

No wonder we feel better after we dance.

[Image licensed under the Creative Commons Ramesh lalwani, Revanta Sarabhai Male Dancer, CC BY-SA 4.0]

For me, one of the most wonderful -- and difficult -- things about dancing is that it requires you to forget about yourself.  To dance fluidly, you need to be immersed in the music and the movement, and overcome the self-consciousness we all seem to carry around with us, to greater or lesser degrees.  I'm plagued with more than my fair share of it, and it's only been fairly recently that I've been willing to dance with other people around.  Which, of course, is missing a good part of the fun of it -- sharing the experience of moving your body in synchrony to the music.

What brings all this up is a fascinating study from the University of Tokyo released last week showing that humans aren't the only ones who feel like shakin' their tails when the music comes on.

Rats do it, too.

Rats were fitted out with tiny helmets containing wireless accelerometers, and then exposed to varying types and speeds of music.  Sure enough -- they began to move their heads in time to the beat.

"Rats displayed innate — that is, without any training or prior exposure to music — beat synchronization most distinctly within 120-140 bpm (beats per minute), to which humans also exhibit the clearest beat synchronization," said Hirokazu Takahashi, of the Graduate School of Information Science and Technology, who co-authored the paper.  "The auditory cortex, the region of our brain that processes sound, was also tuned to 120-140 bpm, which we were able to explain using our mathematical model of brain adaptation...  Music exerts a strong appeal to the brain and has profound effects on emotion and cognition.  To utilize music effectively, we need to reveal the neural mechanism underlying this empirical fact."

I find this absolutely astonishing, given that rats don't have music in their natural environments (well, except for the rats that sometimes end up cohabiting with us).  What possible purpose can this serve?  It's interesting, but it seems to me to raise as many questions as it answers.

Which, of course, is the hallmark of good science.

Whatever the reason, it's pretty cool that this impulse to move to the music has a long evolutionary history.  And there's no doubt that it does a body good.  I'll end with a quote from the wonderful writer Dave Barry: "Nobody cares if you can't dance well.  Get out there on the floor and dance anyway."

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

Choosing the right path

We're all so familiar with our own mental internal state that it's interesting to consider (1) that not everyone has the same sort of thing going on in their brains, and (2) what's really going on in there is not at all obvious.

I was just discussing the first bit last night with a friend.  She told me that she has entire, back-and-forth conversations in her mind, pretty much constantly.  Asking herself things, musing over answers, as if she was on both sides of a discussion over what to do and how to do it.  Me?  I have a crazy, trippy, disjointed monologue, jumping from topic to topic, as if my skull was occupied by Daffy Duck on speed.  And generally there's a soundtrack, too, usually of whichever song I heard on the radio over the past 48 hours was the most annoying.

It's no wonder I have such difficulty focusing.

Some people are highly visual, and rather than words, they think in pictures.  No internal chatter at all, which is hard for me to imagine.  And I guess it's no surprise I don't think in images much, especially not images of people; being face-blind, I can't picture anyone's face, including my own.  Nada.  I know I have blond-ish hair and blue eyes and short facial hair and a big nose, but I can't put it all together into a composite image the way some people (apparently) do with ease.

Of course, in most ways I get by just fine.  I was asked one time, "If you can't picture your own face at all, how do you know it's you when you look into the bathroom mirror in the morning?"  I stared at the person for a moment, and said, "Because I know there's no one else in the bathroom but me."

I mean, I may be face-blind, but fer cryin' in the sink, I'm not stupid.

But I digress.

Anyway, there seems to be a huge variety of internal experience, which I suppose is what we should expect given the huge variety of outward expressions of that experience.  But that brings us to the second question: what's happening inside our skulls that creates that internal experience in the first place?

Neuroscientists are just beginning to piece together an answer to that question.  We have a pretty good idea of where in the brain certain activity occurs; higher-order processing in the prefrontal cortex, motor coordination in the motor cortex and cerebellum, spatial navigation in the hippocampus, speech production in the Wernicke's and Broca's areas of the cerebrum, and so on.  Even my own particular difficulty, which goes by the medical name prosopagnosia, has been localized to a place called the fusiform gyrus, which in the face-blind simply doesn't respond when confronted with an image of a face.  So we can see it just fine, but we don't recognize who it is.  (It manifests in me as everyone looking vaguely familiar -- so when someone starts talking to me, I can usually slip right into acting like I know who I'm talking to, when in fact I very rarely do until I recognize the voice or pick up context clues.  But I'm good at faking recognition, at least until I get fed up fishing around and say, "I'm sorry, but I have no idea who you are.")

But other than the general locations in the brain where certain functions occur, we're still largely in the dark.  Think about something really simple that isn't in your mind before the question was asked -- for example, what did you have for dinner last night?

Now, where was that information before I asked the question?  How was it encoded?  How did you retrieve it?  Even weirder are those moments when you know you know a piece of information, and it's in there, but you can't get at it -- the "tip of the tongue" phenomenon.  And why, when you stop worrying at it and start thinking about other things, does the answer spontaneously pop out?  (In the days before Google, when finding out factual information usually required a trip to the library, I was driving myself nuts trying to remember the names of the Three Musketeers.  Athos, Porthos, and...?  It was a full two days later, while I was out for a run and completely thinking about other things, that suddenly my brain went "... Aramis!")

What about when we're trying to make a decision between two alternatives?  For me, I'll bat back and forth between them, then -- quite suddenly -- I settle down into one or the other.  And just last month a paper in Cell has suggested that what's going on in the brain might be exactly what it feels like, only much, much faster.

In "Constant Sub-second Cycling between Representations of Possible Futures in the Hippocampus," a team led by neuroscientist Kenneth Kay of Columbia University found that rats confronted with a choice in maze-running shuttle back and forth quickly (about eight times per second) between patterns of neural firing representing the two choices -- as if they were thinking, "Let's see, I wonder what's down the right-hand path?  Hmm, how about the left-hand path?"

The authors write:

Cognitive faculties such as imagination, planning, and decision-making entail the ability to represent hypothetical experience.  Crucially, animal behavior in natural settings implies that the brain can represent hypothetical future experience not only quickly but also constantly over time, as external events continually unfold.  To determine how this is possible, we recorded neural activity in the hippocampus of rats navigating a maze with multiple spatial paths.  We found neural activity encoding two possible future scenarios (two upcoming maze paths) in constant alternation at 8 Hz: one scenario per ∼125-ms cycle...  Notably, cycling occurred across moving behaviors, including during running.  These findings identify a general dynamic process capable of quickly and continually representing hypothetical experience, including that of multiple possible futures.

There are a couple of interesting things about this.  First, there's the role of the hippocampus; higher-order decision-making is traditionally thought to be the provenance of the prefrontal cortex, although the fact that this decision has to do with spatial navigation is probably why it occurs where it does.  Second, why is the cycling so fast -- each flip lasting, on average, an eighth of a second -- when it feels very much like we're considering each possibility slowly and deliberately?  (Of course, that's assuming that our neurology and experience are both comparable to what's happening in rats, which may be a poor assumption.)

I also wonder what's happening with the consideration of imaginary scenarios.  Being a fiction author, I do that a lot, and I know I spend a great deal of time testing out various ideas and plot twists before settling on the one that I want.  It's quite remarkable when you think about it; we're capable of dreaming up highly detailed and completely counterfactual scenes, and interact with them as if they were real -- deciding which path to take, which of the two magical doors to open.

As author and journalist Kathryn Schulz put it, in her phenomenal TED talk "On Being Wrong," "The most wonderful thing about the human mind is not that we can see the world as it is, but that we can see the world as it isn't."

But this is just the first step of solving that most fundamental of questions in neuroscience, which is how we emulate our experience in our brains.  This is one small piece of the puzzle of human consciousness, the origins of creativity, imagination, and memory, the last-mentioned of which hopefully will solve how I can set a tool down and literally thirty seconds later can't remember where I put it.

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

One of my favorite people is the indefatigable British science historian James Burke.  First gaining fame from his immensely entertaining book and television series Connections, in which he showed the links between various historical events that (seen as a whole) play out like a centuries-long game of telephone, he went on to wow his fans with The Day the Universe Changed and a terrifyingly prescient analysis of where global climate change was headed, filmed in 1989, called After the Warming.

One of my favorites of his is the brilliant book The Pinball Effect.  It's dedicated to the role of chaos in scientific discovery, and shows the interconnections between twenty different threads of inquiry.  He's posted page-number links at various points in his book that you can jump to, where the different threads cross -- so if you like, you can read this as a scientific Choose Your Own Adventure, leaping from one point in the web to another, in the process truly gaining a sense of how interconnected and complex the history of science has been.

However you choose to approach it -- in a straight line, or following a pinball course through the book -- it's a fantastic read.  So pick up a copy of this week's Skeptophilia book of the week.  You won't be able to put it down.

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

Mice, rats, and sunk costs

One of the most difficult-to-fight biases in human nature is the sunk-cost fallacy.

The idea is the more time, effort, and/or money we've put into a decision, the less likely we are to abandon it -- even after it has been proven a bad choice.  It's what makes people stick with cars that are lemons, investments that are financial disasters, marriages that are horrible, and politicians who have proven themselves to be unethical and self-serving, long after cut-and-run would, all things considered, be the most logical course of action.

The tendency is so ubiquitous that it's often taken for granted.  You even see it in far less logical scenarios than the ones I mentioned above, where there could be at least some rational reason for sticking with the original choice.  A good example is games of pure chance, where gamblers will keep on wasting money because they are certain that a losing streak is bound to end.  "I'm already a thousand dollars in the hole," they'll say.  "I can risk five hundred more."  Here, sunk-cost makes no sense whatsoever; the lost thousand is not an investment that could pay off in any sense of the word, and losing streaks in games of pure chance are not bound to do anything.

That's why they're called "games of pure chance."

So the ubiquity of the sunk-cost fallacy is undeniable, but what's less obvious is why we do it.  Sticking with a bad choice is rarely ever advantageous.  But despite its dubious benefits to survival, what seems certain is that it's a very old behavior, evolutionarily speaking.  Because researchers at the University of Minnesota have just shown that sunk-cost decision making not only occurs in humans, but in...

... mice and rats.

[Image licensed under the Creative Commons Rasbak, Apodemus sylvaticus bosmuis, CC BY-SA 3.0]

In a paper entitled "Sensitivity to 'Sunk Costs' in Mice, Rats, and Humans" that appeared last week in the journal Science, neuropsychologists Brian M. Sweis, Samantha V. Abram, Brandy J. Schmidt, Kelsey D. Seeland, Angus W. MacDonald III, Mark J. Thomas, and A. David Redish showed that even our very distant relatives engage in sunk-cost errors.  The authors write:

Sunk costs are irrecoverable investments that should not influence decisions, because decisions should be made on the basis of expected future consequences.  Both human and nonhuman animals can show sensitivity to sunk costs, but reports from across species are inconsistent.  In a temporal context, a sensitivity to sunk costs arises when an individual resists ending an activity, even if it seems unproductive, because of the time already invested.  In two parallel foraging tasks that we designed, we found that mice, rats, and humans show similar sensitivities to sunk costs in their decision-making.  Unexpectedly, sensitivity to time invested accrued only after an initial decision had been made.  These findings suggest that sensitivity to temporal sunk costs lies in a vulnerability distinct from deliberation processes and that this distinction is present across species.

In both the experiments with humans and rodents, the setup was the same -- the subject navigates a maze looking for rewards (a food pellet for the mice, and hilariously, a video of kittens playing for the humans, showing that cat videos really are an incentive for us) which are scattered randomly through the maze.  Each time a reward is encountered, the subject is told how long it will take for the reward to be delivered (a tone the mice and rats are trained to associate with wait time, and a countdown timer for the humans).  Because the rewards are plentiful and some of the waits are long, what would make logical sense is to abandon a reward if the wait time is too long, so more time could be spent searching for rewards with short wait times.

But that's not what happened.  Both the rodents and the humans would often stick with rewards with very long wait times -- and the ones who said, "Screw it, this is too long to sit here twiddling my thumbs" all gave up early on.  The longer the test subject stuck with the wait, the more likely they were to hang on to the very end, even at the cost of a considerable amount of time that could have been spent foraging more productively.

"Obviously, the best thing is as quick as possible to get into the wait zone," said David Redish, who co-authored the study.  "But nobody does that.  Somehow, all three species know that if you get into the wait zone, you’re going to pay this sunk cost, and they actually spend extra time deliberating in the offer zone so that they don’t end up getting stuck."

What this research doesn't indicate though, its why we all do this.  Behaviors that are common throughout groups of related species -- what are called evolutionarily-conserved behaviors -- are thought to have some kind of significant survival advantage.  (Just as evolutionarily-conserved genes are thought to be essential, even if we don't know for certain what they do.)  "Evolution by natural selection would not promote any behavior unless it had some — perhaps obscure — net overall benefit," said Alex Kacelnik, a professor of behavioral ecology at Oxford, who was not part of the study, but praised its design and rigor.  "If everybody does it, the reasoning goes, there must be a reason."

But what that reason is remains unclear.  We have to leave it at "we're not as logical as we like to think, and our motivation for decision-making not as based in solid fact as you might expect," however unsatisfying that might be.

But it is something to consider next time we're weighing the benefits of sticking with a decision we already made -- whether it's the wait time for downloading a kitten video, or continuing our support for a politician.

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

This week's Skeptophilia book recommendation is a must-read for anyone concerned about the current state of the world's environment.  The Sixth Extinction, by Elizabeth Kolbert, is a retrospective of the five great extinction events the Earth has experienced -- the largest of which, the Permian-Triassic extinction of 252 million years ago, wiped out 95% of the species on Earth.  Kolbert makes a persuasive, if devastating, argument; that we are currently in the middle of a sixth mass extinction -- this one caused exclusively by the activities of humans.  It's a fascinating, alarming, and absolutely essential read.

Diseased cannibal rat ship

In the last few days we have a new story circulating in the media, and this has led to considerable buzz on Facebook and Twitter.  Comments I've seen have included, "Yuk," "This is horrible," "Terrifying!," and "The government better do something about this, soon!"

Not once have I seen anyone post my immediate reaction, which was, "Okay, really?"

The story has appeared on various woo-woo websites, but has also made it onto Fox News and The Independent.  Here are excerpts from the version that appeared on Stranger Dimensions, entitled, "Is a Russian Ship Filled With Diseased Cannibal Rats Heading Toward the UK?"

Experts believe a derelict cruise ship that’s been missing for a year may be en route to the U.K. The problem? It’s filled with disease-ridden cannibal rats.

Built in Yugoslavia in 1976, the Lyubov Orlova was a cruise liner that had for many years transported passengers to destinations around the world. Unfortunately, in 2010, the ship was impounded in Newfoundland, Canada and deserted by her crew. Two years later, while being towed to the Dominican Republic to be scrapped, a heavy storm caused the tow-line to break, sending the Lyubov Orlova out to aimlessly wander the North Atlantic Ocean...

Now, a year later, new concerns are being raised that the ship is heading for the U.K.

It’s completely empty, save for the potentially hundreds of diseased rats aboard the ship that have most likely been forced to eat one another to survive.

Diseased cannibal rats!  By the millions!  Waiting for their chance to get onto land, and rush around swarming over and eating innocent British citizens, like a scene from the movie Willard!

[image courtesy of the Wikimedia Commons]

But then we hear what data these "experts" are currently going on:

Over the following months, the Lyubov Orlova was spotted at various locations in the North Atlantic. In one instance last year, satellites found an object near Scotland that may have been the ship, but subsequent searches in the area found nothing...

Discerning readers may point out that the ship’s emergency position-indicating radio beacon had activated off the Kerry coast on March 1, 2013 after presumably being submerged in water, implying that the ship had, indeed, sunk. However, authorities say some of the life-boat emergency signals have yet to activate, and the ship may still be out there, diseased cannibal rats and all.

The ship’s current position is unknown, but due to recent high winds, experts fear the ghost ship may be on a crash course for the British coastline. If they’re right, the Lyubov Orlova is likely to wind up on the west coast of Ireland, Scotland, or southern England. What happens if/when it gets there? I don’t know, but…diseased rats. Can’t be good.  

That's right; there was a beacon signal detected in March of 2013, and it was "maybe" spotted by a satellite later that year -- and no one has had a glimpse of it since then.  The ship's current position is unknown.

Remember a couple of days ago, our discussion of what the word "unknown" means?

But then what went through my mind was: even considering that the ship may be out there, how do they know about the rats?  Were they detected on the satellite, baring their decay-ridden fangs defiantly at the sky?  Okay, presupposing that any ship is gonna have rats, still... how would anyone know that they're diseased cannibal rats?  When the beacon went off, did the people who picked it up hear, in the background, the sound of hoarse, coughing squeaks, as if a diseased rat were being savagely dismembered and eaten by its pack mates?

I know that the whole thing was written for no other reason than to get people stirred up, but what bugs me is that hardly anyone seems to be questioning how the writer of the article knows all of this stuff.

Oh, but to hell with the facts; the diseased cannibal rat ship may still be out there.  And if it may still be out there, then it might be headed for England.

Even the Wikipedia article on the Lyubov Orlova has been contaminated by this silliness; the last paragraph of the article is, "Certain independent researchers and amateur salvage hunters have also stated that a population of rats are on board the vessel, and that in the absence of edible food, the rat population have turned cannibalistic.  The opportunity to study the cannibalistic rats has been welcomed by researchers."  (Although I will say that at least someone appended "citation needed" after this paragraph.)

Well, I think we can do better than this, can't we?  Let's see... back in 1950, a ship called the Phoenix went missing off the coast of Australia.  It was last seen near Darwin, but no word of it was heard from thereafter.  But it could still be out there.  Carrying a load of... cannibalistic kangaroos and feral wombats.  Experts can't be certain that this is wrong.  And maybe by now, it's drifted across the Pacific, and is on a collision course with San Francisco.  What would happen if it ran aground near the Embarcadero, depositing its cargo of hopping, waddling death into the waterfront cafés and shops filled with unsuspecting tourists?

I don't know, but it can't be good.