Archive for March, 2012


As a graduate student, one of the first courses I was required to take was a proseminar on animal behavior, taught by Howard Topoff.  As an undergraduate, I had gotten a smattering of evolution, but probably like many of you, I did not really have a good grasp of what exactly it was.  That was soon to change in Howard’s course.  We spent quite a lot of time discussing reproduction and evolution, and how those came into play in animal behavior.  I recall one lecture where he showed us a species of fish with a giant eye spot near its tail, very similar to this guy here, the foureye butterfly fish.

The front end of this fish (eyes and mouth) are actually on the right side of the picture.  That giant spot you see is near the tail, on the left.  It gives this fish a very disorienting appearance, which is exactly the point.   Imagine being a predator looking for a quick meal, and seeing that big ugly eye flashing at you.  I’d be intimidated, too!

Hopefully, you can see the value in this giant eye spot.  However it arose (as a random mutation, or it served some other purpose, it is hard to say), those fish that had it tended to survive long enough to produce offspring.  In doing so, they passed this trait along.  It stays in the species as a feature whether it continues to be useful or not.  As long as it keeps predators away, it is useful.  If all the predators that used to come after it somehow disappear, the trait stays because there’s nothing selecting against it (i.e. there’s no pressure from the environment to do away with it because fish without it survive longer and produce offspring).

So this was the kind of stuff I was learning in graduate school.  But Howard was quick to caution us against “telling stories,” as he put it.  Hindsight is 20-20, and it is easy to come up with what seems like a plausible explanation for something to fit the adaptationist paradigm without any real evidence.  So, while it is a useful exercise, to consider why particular traits might have been selected, it should be done with a few caveats in mind.

This is the thesis of the scholarly article,  The Spandrels of San Marco and the Panglossian Paradigm:  A Critique of the Adaptationist Programme by Stephen Jay Gould (pictured here) and Richard Lewontin, which my professor had undoubtedly read by the time I took the proseminar in animal behavior from him.   Gould and Lewontin, in this 1979 article which is at least in part a critique of E.O. Wilson’s theory of sociobiology, argue that adaptationists and evolutionary psychologists sometimes go too far in attempting to explain every trait of an organism in terms of function.  According to them, organisms must be regarded as a whole organism, rather than as a conglomeration of individual traits that all evolved to solve a particular function for the organism.  By focusing on traits, Gould and Lewontin say, you lose sight of the whole.

They use an architectural metaphor to make this point.  The feature in question is a small triangle created when arches come together, known as a spandrel, pictured here.  This feature, often found in cathedrals and other large structures with arched ceilings, is usually filled with elaborate decorations.  We would, however, never analyze the spandrel before us, when we stand in such places, and think that they are anything more than a by-product of the arch placement, used to great effect by painters and mosaicists.  They are not the starting point from which the arches then become necessary. We have no trouble seeing the by-products in a non-biological system here, but when it comes to traits in organisms, we often engage in “telling stories” as my professor, and Gould and Lewontin, suggest.  This comes from the perspective that all the traits that make up an organism, from the shape of their limbs to the brain that gives rise to specific behaviors, are the product of and therefore constrained by the mechanisms of natural selection.  There is no place for the biological equivalent of a spandrel in this perspective.

If we stop and think about it, the idea that there could be by-products of natural selection, properties of the nervous system that emerge unexpectedly and unpredictably from a collection of traits, for example, makes a lot of sense.  I have an entire lecture on evolution and its role in behavior, in which I argue that everything that our nervous system does, evolved to help us navigate the world more efficiently and effectively.  I do not think this perspective is wrong, but I did allude to two properties of the nervous system in those introductory lectures, that fit into Gould and Lewontin’s perspective of emergent properties perhaps better.  Those two topics were mirror self-recognition and the appreciation of a beautiful sunset.  I think I could “tell a story” about each of these to show how they’re adaptive (and I think I even did).

But, lets take a step back and look at each of those as an emergent property of the nervous system rather than a trait that represents a particular adaptation to the environment.  So, the appreciation of a beautiful sunset arises in much more of a gestalt sense, from certain features of the nervous system, such as color vision and the experience of emotion.  With these two things in place, our big and powerful brains took these capabilities and used them in a way that went far beyond the sum of their parts, giving us an aesthetic sensibility that other species likely do not possess.  Similarly, the ability to recognize yourself in a reflective surface did not evolve for a specific reason; it is an emergent property of a cognitively and physiologically complex brain.  It is no surprise that species with larger brains tend to show this trait, and it develops in human children right after a substantial increase in the number of neurons and synapses in their brains.

So, a little food for thought. I could not resist the temptation of “telling stories,” because it is a fun exercise to look at a particular behavior and see into the past for a few moments.  But sometimes, it is equally important to take a step back from that and look at a behavior in a much broader context.

Next week, I will be posting about an article on ketamine, glutamate, and anti-depressants.

References:

Gould, S.J. and Lewontin, R.C. (1979). The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme. Proceedings of the Royal Society of London, Series B. 205(1161), 581-598

Reiss, D., and Marino, L. (2001). Mirror Self-Recognition in the Bottlenose Dolphin: A Case of Cognitive Convergence. Proceedings of the National Academy of Science, 98(10), 5937-5942. 10.1073/pnas.101086398

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The first time I taught a course like this, I convinced myself that the best approach would be bottom-up, to start small and work my way up to the larger brain systems.  Dutifully, I started the course with a detailed lecture on the structure of the neuron, before moving on to action potentials and the activity of neurotransmitters.  This isn’t a bad way to begin the course, and makes a kind of intuitive sense.  But from a student perspective, it probably comes across as very abstract and disconnected from behavior.  It really isn’t, since without action potentials there probably wouldn’t be much behavior, but for students new to the material, or with only a bit of it under their belt from Introduction to Psychology, I can see how jumping into biological psychology this way can be disorienting.

To try to “cushion the blow” so to speak, I decided to open the course with much broader themes, and begin with a discussion of consciousness*.  In the lecture I talk about animism , a belief that animate and inanimate objects have some kind of animating spirit that accounts for movement.  Tides, rocks, and even living creatures had some animating force inside them that compelled them to move.  And, while a belief that rocks and trees and fish are inhabited by some intangible spirit is not quite as popular as it once was, certain aspects of this belief system persist.  While our consciousness is a definitive part of ourselves, I think many people also have the sense that our consciousness is a separate entity as well.  Certainly, the religious concept of the soul stems from this idea.  Like the animating spirits some of our ancestors believed in, many people believe there is a part of us that will continue on once our physical self has died, and that this non-corporeal, intangible animating spirit makes up the bulk of our identity.

From that discussion, I then go on to talk about consciousness as a property of our nervous system.  This perspective comes from another philosophical school of thought, called materialism, which holds that the universe is composed of matter, and that all things in the universe, including consciousness, result from interactions between matter.  I was immediately drawn in by how two such seemingly disparate perspectives on the universe could meld together.  And disparate they are, I think.  Inherent in the philosophy of materialism as it relates to consciousness is the understanding that when our corporeal form ceases to exist, so does our consciousness.  There is no animating spirit that will live on past our physical life, because the mechanism that produced the spark of life in us has gone.  Not everyone who studies consciousness believes this is the case, but I think the idea is certainly a rational conclusion.

And yet, the notion that our consciousness is somehow separate from our physical being is unshakable for many.

So the course opens with a discussion about consciousness as a property of the brain and nervous system, and I think that works very well to create interest, if not necessarily agreement.  We all know that our nervous system drives the bus, so to speak, but I think few of us really consider what that means.  Complex, abstract behavior, such as creativity, curiosity, and imagination are all properties of our nervous systems, as is consciousness.  In fact, consciousness is the umbrella sitting over not only these complex, abstract behaviors, but our everyday mundane behaviors like walking, eating, and so forth, though to a lesser extent most of the time.  (When was the last time you really had to think about walking as you did it?  Still, a part of us is conscious that we are, indeed, walking as we do it.)

After consciousness and a few other broader topics, we then delve into the electrochemistry of the nervous system, because that stuff is important.  More importantly, it’s fascinating–we see our ancient ancestry from the sea in the salt water that not only bathes our nervous system, but provides the electrochemical basis for action potentials, neurotransmitter release, and ultimately behavior.

*This is a recent article in Time about consciousness and some of the research being conducted to understand it.  Well worth taking a few moments to read.

I’ve spent the morning organizing the course material in preparation for uploading it.  The biggest change the course will receive is cosmetic–I’m re-rendering all the video content into Flash video.  The RealPlayer format worked all right for the first few iterations of the course, but I would like the video to be of better quality.  I tested out the use of flash in my hybrid statistics course, and there seemed to be fewer problems accessing the material.

I also want to make a few edits to some of the video, which seems logical since I’m re-rendering them.  Now that the course has been run in an online format for a few semesters it’s time to polish it a little.  I know a lot more about preparing online content than I did when I started this adventure, and I’d like to put that knowledge to good use.

The biggest addition to the course will, of course, be this blog as well as your blogs.  I’ll be posting more information about this assignment in the days to come.  I believe you will find the experience enjoyable–it represents a way for you to organize your thoughts on the material, and synthesize some of the information in a creative medium.  That this will be shared with and commented on by your fellow students is an exciting bonus.  Peer feedback is especially valuable in writing, and I think you will find the experience challenging, but beneficial.