WARNING: This post is jargontastic.  I’ve included lots of Wikipedia links, but it still may be difficult for readers unfamiliar with certain concepts or unaccustomed to my blather.  If this is a greater challenge than you find enjoyable, then do skip it.  I hope to return to these concepts in a more cumulative fashion, one day, when I explore cognitive science in its proper time period.

So … I watched part 2 of Becoming Human.  It’s been a while since I watched it, and to be honest, I haven’t retained many of the details.  But what I do remember is that it got me thinking about human intelligence.  So here are some of my musings…

Individual organisms frequently use specific behaviors to benefit themselves and sometimes their families / communities / etc….  These behaviors can range from very simple to vastly complex.  At what point do we start calling the behaviors “intelligent” and at what point does the intelligence become uniquely human (if ever)?  I’ll start by trying to break down advantageous behaviors into levels of complexity.  If I’m lucky, that may also suggest an evolutionary progression.

Starting with the simplest, we have unconditional behaviors.  Consider the beating of a heart.  This is an oversimplification, of course, because the beating of a heart is often modulated in fairly sophisticated ways, but it’s basically set up to keep on beating.  The behavior is unconditional.  It’s easy to imagine how natural selection could result in the prevalence of many such behaviors.

Now consider the euglena – a type of single-celled organism with a flagellum it uses for locomotion.  It also has an eyespot that it uses to see how much sunlight it’s getting.  If it’s getting plenty of sunlight for photosynthesis, it doesn’t bother wagging its flagellum.  Why waste energy and risk propelling itself into shadow?  But if it’s dark, what has it got to lose?  It will die without a source of energy.  I’ll call this a sensory-dependent behavior.  The behavior always depends on what the organism is sensing right now.  Lights go out: flagellum goes to town.  It doesn’t have to be that simple, though.  The behavior can be determined by many sensory inputs.  In this way, sensory-dependent behavior is analogous to combinational logic circuitry in digital electronics.

To extend the electronics analogy to sequential logic, we progress to what I’m calling sensory-state behavior.  This type of behavior depends on the current sensory input as well as some “remembered” internal state which can be altered by changes in the sensory input, by the passage of time, and sometimes by a stochastic (i.e. unpredictable or “random”) component.  The “randomness” is likely to be actively utilized only where predictable behavior is disadvantageous.  Suppose our euglena friends live in any environment in which sunlight is often blocked transiently by passing objects overhead.  It may be that most periods of darkness are so short that actuating the flagellum immediately costs more energy than it yields.  Perhaps, then, a calculated delay would help.  If it gets dark, you wait a certain amount of time before you seek sunnier pastures – that way, you don’t waste energy on all those brief periods of darkness.

The sensory-state paradigm can also be much more sophisticated.  To make our example slightly more robust, what if the euglena also remembers (in its internal state) the recent frequency and average duration of the periods of darkness?  Now it can optimize its delay to suit the characteristics of a dynamic environment.

If adaptability to changing environments is what an organism needs, then it might make sense to move on to my next “level of complexity”: sensory-state-learning behavior.  This employs some set of feedback signals that reinforce behaviors leading to to primally positive outcomes (e.g. food!  yum!  good!) and discourage behaviors leading to primally negative outcomes (e.g. hunger!  starvation!  BAD!).  The feedback is used to “reprogram” the behavior to adapt to environments that change rapidly in unpredictable ways.  The feedback signals can be equated with the basic sensations of pleasure and pain.

Computational theory buffs will be quick to point out that sensory-state behavior is capable of doing anything that sensory-state-learning behavior can do.  And they’re right!  From a theory of computation standpoint, anyway.  Sensory-state behavior is Turing complete – it can emulate sensory-state-learning behavior.  The distinction between the two levels of complexity assumes that the implementation substrate requires more energy and attains less stability in maintaining its internal state than its underlying behavioral programming.  For behavior implemented using neurons, as in the human brain, that seems to be the difference between memory using neural feedback (analogous to flip-flops in digital logic or RAM in a computer) and long-term potentiation (more analogous to non-volitile memory, such as a hard drive).  It may be too energy-expensive to implement adaptive learning through sensory-state behavior, but if the underlying circuitry can be changed instead, it becomes worth it.

This is great for avoiding that thing that burns you and not pushing your limbs outside their safe ranges of motion.  It works to teach you the way home that has fewer scary run-ins with predators.  It could even help you refine any beneficial tool use you stumble into.  But it doesn’t explain where abstract thinking comes from – it doesn’t tell us why humans can create mental models of their world that allow them to predict which courses of action will likely yield the most favorable results.  For that, I suspect, you need sensory-state-learning-self-training behavior.  I’ve created a Hyphen-Monster.  The added ingredient is that the feedback signals that train the behavioral circuitry can come not only from the senses, but also from the outputs of the behavioral circuitry themselves.  Feedback sensations like “pleasure” and “pain” take on internal analogs not directly linked to the senses.  Thus, for instance, humans could experience either “physical pain” or “emotional pain”.

These internal feedback signals would allow an organism to learn not only behaviors, but also new ways of learning behaviors and ways of systematically modifying behaviors.  These “meta-behaviors”, I believe, could be the basis for rational thought, complex emotion, and even language.

I am not an expert in biology, psychology, cognitive science, or neuroscience.  But many of my friends are!  I hope they, and others, will comment on this post to let me know how this fits with ideas in those scientific communities and with their own ideas.

Thank you very much for reading!

I can see why the foil tape would work so well.  When I unwrapped it there were indentations on it from the imperfections in the shrink wrap and new ones as soon as I touched it with a fingernail.  I’ll probably have to discard several layers of it to get a smooth recording surface.

And of course, wood and sheet metal…

The whole thing was notably expensive, but I keep reminding myself that I’ll get a lot of use out of some the items.  I’m especially excited about the power drill / driver set.

Thanks for reading!

Things I’ll need that I already have:

• Tuna can for sound chamber
• Hard plastic for diaphragm (I’ll try a CD case as suggested in the addendum.)
• Cardboard (It is a special thrill whenever a use for cardboard presents itself.)
• Thumb tacks (I’m going to try using one of these as the needle.)
• Heavy aluminum foil (Although I’m going to try to use the aluminum foil duct tape recommended in the addendum.)
• Duct tape

Things I think I can get from other people:

• Manila file folder (I think I can get an old one at work.)
• Wire hanger (I believe my roommate is looking to get rid of some.)

Things I can get at hardware store(s):

• Plywood and pine
• Screws, nuts, & washers (I may very well have what I need, but I have it randomly distributed in plastic bags hidden in dark recesses of boxes I’ve moved with several times without opening.  Let this be a lesson to me!)
• Sheet metal
• Drawer knobs
• Wood glue & epoxy
• Aluminum foil duct tape

Things I can get at a craft store:

• Felt

Things I probably have to order:

• 1/4″ pre-threaded stock shaft

Tools I’ll need that I already have:

• Screw driver(s)
• Can opener (for the tuna)
• Scissors (for the cardboard, felt, & foil/tape)

Tools I want to buy:

• Drill (I can probably borrow use of a drill press, but given the things I plan to do, it’s worth owning one.)
• Hand saw (Once again, I can borrow use of something fancy, but I should have one handy too.)

Gerald Fabris, Curator of the Edison Historical Site in West Orange, NJ, gave a demonstration of wax cylinder recording and playback at the Boston Public Library on Tuesday.  It was a fascinating presentation.  It turns out the phonograph was preceded by a device called a phonautograph.  This worked similarly to a traditional seismograph: a moving stylus draws a waveform on a long, scrolling sheet of paper.  In this case, the stylus is attached to a diaphragm which vibrates with the compression and rarefaction of the air.  So the stylus is drawing sound waves.  The inventor of the phonautograph, Édouard-Léon Scott de Martinville, had no way to play back his recordings, but quite recently the documents were scanned into computers and turned back into sounds for the first time.  The sounds were played during the presentation.  It was very muddled, but it definitely sounds like a human voice!

Thomas Edison’s phonograph worked the same way, with a diaphragm vibrating with the sound waves, but instead of drawing back and forth on paper the stylus pushed in and out against a rapidly spinning, slowly advancing, tinfoil covered cylinder.  In this way, the stylus digs a helical grove into the tinfoil with varying depth.  The pattern of changing depth, of course, encodes the sound wave.  The process is reversed for playback.  A more blunt “needle” presses against the groove as the cylinder spins.  The needle, in turn, pushes a diaphragm.  As the needle is pushed in and out by the varying depth of the groove, so is the diaphragm – and the recorded sound is reproduced.

Through the years the material of the recording surface and many other details of implementation were altered and refined.  I’m not going to attempt to replicate any particular historical phonograph.  I’ll pick what I see as the most practical way to prove the concept.  I’ve found several guides on the internet for how to build a simple phonograph.  I’m going to see how well this one works for me: http://www.creative-science.org.uk/RS2phono.html.

I’ll try to interleave my work on this with the throwing spear discussion.  For the paleolithic era, I plan to make my throwing spear, finish watching Becoming Human, and possibly visit a museum or two.  Then I’ll move on until the weather gets warmer.  Then I’ll go back and finish some of the outdoor paleolithic activities such as fire-making and shelters.

Thank you for reading!

Here are some photos for you…

Pascale sent me this image of the tongue before cooking to provide a sense of scale.

Frozen.

Ready to eat! It came with lentils and Pascale said it would taste best with mustard.

And here’s the recipe that Pascale used: http://www.wasabibratwurst.com/pickled-tongue/

It was delicious!  I admit I was a little freaked out about eating tongue, but it wasn’t all that different from any other meat.  It had a distinctive texture and flavor, but at least in this preparation, it was surprisingly tender.  Thank you Pascale!

And, of course, thank you for reading.

In any case, check out the group and see if you find any events that interest you.  You probably will and maybe I’ll see you there!

Thanks for reading!

I don’t mark up the prices at all.  It’s just for fun and to promote the blog.

Thanks for reading!

The main question that “First Steps” attempts to answer is that of what evolutionary forces led the ancestors of modern humans to walk upright and then to become more intelligent and to create tools.  The documentary focusses on relatively recent hypotheses.  Namely, in the case of bipedalism, that it is simply more energy-efficient to walk on two feet.  The energy savings might not seem like a big deal, but this idea makes a lot of sense to me because of my own personal experience.  I have a permanent foot injury that prevents me from putting a lot of pressure on my right heel.  Although many people don’t notice it until they’ve been around me for a while, I always walk with at least a slight limp.  When walking at a comfortable pace, this doesn’t make much difference.  But when I start running or jumping rope it becomes obvious that I’m not doing it the way it’s normally done.  I’m quite fortunate that I’ve been able to adapt and that I can still walk, run, and jump when I need to, but I don’t do it as efficiently as I would without the injury.  When I’m walking and tired I know I really miss heel strike and I imagine it would matter even more if I were struggling to get enough food.

“First Steps” cites a change in our ancestors’ natural habitat as the driving factor for that change: they needed to walk farther each day to stay alive.  The changing environment is also cited as the catalyst for our increased brain size and intelligence.  Geological evidence shows that at the time when homo habilis (the first tool-making ancestor of modern humans) emerged, the climate was frequently and drastically shifting.  Ordinarily, when the environment changes, natural selection would produce creatures whose physical traits and hardwired behaviors were well suited to the new environment.  But that takes many generations to occur.  If the climate is changing dramatically every few generations, then biological evolution can’t keep up.  What it can do is allow a new kind of evolution to emerge – one that can adapt much faster.  To put it in the terms of my earlier post, they needed software which can be upgraded faster than hardware.

I look forward to watching the next part of this trilogy.  Part one was very informative.

Thank you for reading.

LINK: Part 2

But first, the matter of the name.  There is some confusion out there on the internet about whether they are called “Cartesian divers” or “artesian divers”.  For a while, it had me confused too.  Cartesian divers are named after René Descartes, so the correct name is “Cartesian divers”, but the spread of the confusion is understandable because “artesian“, as it happens, also has a meaning related to fluid mechanics.  There used to be a province in France called Artois where a lot of the water under the ground was under pressure.  If you drill a well in such a place, water will flow up through the well without any pumping.  In Artois many such wells were drilled to take advantage of the effect.  Wells like that came to be known as “artesian”, named after the province.

Next, I’ll explain the way I learned to make a Cartesian Diver when I was little.  It involves two test tubes (one little, one big), a small piece of sheet rubber (e.g. cut from a rubber glove), and something to hold the rubber on the big test tube (recently I used a rubber band and duct tape).  You fill the big test tube with water and put it aside.  Then you filled the little test tube with water leaving just enough air so that it floats when you put it upside down in water.  You either have to flip it really fast, use a tiny test tube so the water stays in due to surface tension, or use a straw to fill it with the right amount of air once it’s in the water.  You put the little test tube upside down into the big test tube, with the air bubble still in the little one so it floats.  Then you attach the rubber sheet seal to off the top of the bigger test tube.

Now, when you press in the rubber with your thumb, the little test tube sinks to the bottom.  When you stop pressing, it floats back up!  How does that work?  By pressing on the rubber, you pressurize the water inside.  Water is an incompressible fluid, so it doesn’t “scrunch together” when you do that.  But air, on the other hand, is very compressible.  So … you’re press on the rubber, the rubber presses on the water, and the water presses on that little air bubble that’s keeping the little test tube afloat.  That compresses (“scrunches up”) the air bubble.  It’s the same amount of air, but in a smaller volume.  That means it gets more dense.  Things that are denser than water sink in water and things that are less dense float.  Remember how we made the air bubble just big enough that the little test tube would float?  Well we just made it a little more dense by compressing it.  So now it sinks!  Release the pressure and it all goes back to normal and it floats back up.

For the kids at Arisia, I tried using balloons instead of bits of rubber glove because I thought they’d be easier to squeeze.  They were easier to squeeze, but they leaked so much that you had to start over again every time you squeezed it!  So after Arisia I searched the internet for the quickest, easiest, and most durable way to make a Cartesian diver I could find.  The easiest method I found was so easy that I felt kind of sheepish for having bothered with test tubes at all!

1. Get an empty, plastic drink bottle.
2. Get a ketchup packet (maybe several different kinds – they don’t all work perfectly).
3. Drop the ketchup packet into the bottle.
4. Fill the bottle with water (all the way to the top).
5. Put the cap tightly onto the bottle.
6. Squeeze the bottle and the packet sinks, release and it floats!

Why does this work?  They don’t fill ketchup packets all the way up with ketchup.  There’s a little bit of air in there.  So… squeezing the bottle pressurizes the water, the water presses on the packet which presses on the ketchup which presses on the air bubble trapped inside.  It turns out that most ketchup packets have just the right amount of that compressible air relative to their weight to make them barely float!  Sound familiar?  Squeezing makes the packet more dense, so it sinks.

It’s unclear who first discovered this method, but here are some websites that describe it: http://littleshop.physics.colostate.edu/Try%20At%20Home/Cart.html, http://scifun.chem.wisc.edu/homeExpts/diver.htm, http://www.wikihow.com/Make-a-Cartesian-Diver-with-a-Ketchup-Packet

Here are some other methods and explanations for how to make Cartesian divers: http://www.lessonplanspage.com/ScienceExCartesianDiver-WhyFallMO68.htm#, http://sealevel.jpl.nasa.gov/education/activities/ts2hiac2.pdf, http://www.dailymotion.com/video/x392vn_cartesian-diver_tech, http://fatlion.com/science/cartesian.html

I know that I had a learning experience at Fast Track this year!  As overwhelming as it was to try to help so many kids at once, I had a great time.  I hope I’ll be able to try again next year with some new activities.

Thank you very much for reading!

That’s right: We’re having a REAL SENATORIAL ELECTION.  This is not a drill!  Go vote.  Polls close at 8PM.  ;-)

Thanks for reading!