Monday, May 3, 2010

School's Out! (But is my joy based in biology?)

It’s the last day of the semester. Students are submitting their final exams to me today and it’s only fitting that I submit my final thoughts to them (and to you) about what I learned this semester about the Biology of Behavior (Anthropology 261).

First of all, it’s mind boggling that after spending an entire semester studying the subject there are students on one hand…

Here’s me with arms outstretched to the sides, palms up.

… who believe that behavior is mostly determined by genes and that one day we’ll be able to explain it all with genetics, and then there are students on the other hand who are super critical of science and also think that behavior is entirely learned.

You’re wondering what this “behavior” is that I’m talking about.

Me too.

Here’s me wincing vulnerably with blushing cheeks.

That’s problem number one. What is behavior? It’s not really clear. Not after a course like this. Maybe my students will illuminate this for me in their final essay in which they categorize human behaviors according to their own taxonomies. But I haven’t read their essays yet.

Here’s me feeling fight-or-flight grading anxiety with tingly palms and armpits.

Problem number two. Everybody, even the most extreme, was on board with Nature PLUS Nurture (as opposed to Nature VERSUS Nurture). So, many of the class discussions boiled down to popular debates, as opposed to more nuanced debates that would have been more productive. But because we couldn’t become experts at this introductory level, it was difficult to get to the nitty-gritty. What we concluded was that the debate about human behavior in the popular media is full of false dichotomies, irrational fears of improbable/impossible future science, and irrelevant debates as a result of both.

Problem number three has to do with normal versus abnormal behavior. People seem to think that because a behavioral disorder can be traced back to genes, then therefore variation in that behavior at the normal level in unaffected people can also be explained by genes.

Here’s me making a wrong answer buzzer sound. Errrrrrr!

So did we figure out why humans do what they do? Well, considering the two choices [(A) It’s instinct. It evolved by natural selection or (B) We learned it. It’s a product of our environment.] The question of why becomes obscured by the possibility that we may not have a choice.

The former choice, A, implies that we can’t help our behavior…We have excuses for behaving badly and we can’t take moral credit for behaving nicely either.

The latter, B, puts the emphasis on culture and its importance…either at the individual level or beyond. Our bad behavior is our own fault or due to our parents, friends, environment, circumstances. Our good behavior is our own doing or it is shaped by parents, friends, environment, circumstances, and by government laws and religion.

So no matter what the answer is, it’s probably going to offend somebody.

Then there are all the behaviors that are neither “bad” nor “good.” The ones that are just what folks do or do not do at various times of their lives, in various circumstances, under various conditions, according to various individual biologies and histories.

Here’s me shrugging my shoulders and throwing my hands up in the air.

The bottom line that everyone agreed on (I hope) is that all behavior is biological even if it’s learned because we are biological beings. Everything we do, learn, say, feel, think is a biological process. Our genes don’t have to determine it for it to be biological. And, it’s all biological unless you invoke supernatural explanations. Human behavior is biological and this goes for whether or not we intend to do what we do.

So what are the determinants of human behavior that all somehow derive from biological processes?

We made a flow chart over the course of the semester and this is the result. Because there are no arrows pointing to any behaviors, this is not a chart of the determinants of human behavior. Instead it is the “Determinants of the determinants of human behavior.” Smart alecs will notice that there are no quantum variables on here and that’s because we didn’t get that small/big this semester.

Hey, at least it’s better than the flow chart for the American strategy in Afghanistan.

Now could you say that explaining human behavior is easier than explaining the American strategy in Afghanistan? That's a good question! But this flow chart may have caused you to wonder, what’s the point of trying to explain human behavior if it’s at least this complex?

Well, there are behavioral disorders we can hope to treat or cure. And there are evolutionary puzzles that we want to solve!

So how’s the treatment of disorders going? One recent example is the search for the genes for stuttering. That the genes linked to stuttering are involved in metabolism is, first of all, surprising to most until they think about how metabolic processes are linked to neurological development. Okay. So what’s the gene? There are three genes where stutterers in the study population had mutations: GNPTAB, GNPTG , NAGPA. So they found the genes for stuttering? Not exactly. Only 6% of stutterers in the sample had these mutations. Only 6%! The other 94% of stutterers are stuttering with perfectly normal versions of these genes. Plus, there are some people in the sample of non-stutterers (albeit a very few, <0.5%). style="">At least for the 6% who do have known mutations, they could see drug treatments soon.

Now, about those evolutionary riddles we’re all dying to solve…

That’s where maternal effects come into play. This is when mom’s genotype or phenotype influences her offspring’s phenotype and maternal effects are known for things like body size, immune function, predator resistant morphology (like spikes or wings). Known triggers are things like resources, density of conspecifics, temperature, parasites, and predators. And these are adaptive! Relatively little is known about maternal effects on behavior, however, it has been reported recently that mother crickets, just by their being around wolf spiders, influence how their offspring react to predators.

Here’s me crouching down and imitating a cricket immobilizing itself as predator-defense.

Mothers who have been exposed to predators have offspring that are better at surviving in the presence of predators than offspring of mothers who have not been exposed to predators.

Here’s me spit-taking my morning coffee because this is just so incredibly mind-blowing.

So if Nature VERSUS Nurture is so passé. And if it all does boil down to biological underpinnings and genes even if the genes don’t dictate things. Then why the rage and the frustration over explaining human behavior? Why the fears that we’re going down the horrific eugenics path by continuing to search for genes for behavior when we probably can’t find genes that determine variation in any of the behaviors that we find especially interesting in normal people?

I think that what offends people most about biological studies of behavior is the simple fear that it might be explained. Learning about human nature and coming up with the explanations for ourselves, by ourselves, is one of the thrills of being a human. It’s something that we want to experience over our lifetimes, not learn from someone else’s simple rules. It’s the idiosyncrasies and the surprises along the way that can be so beautiful and meaningful and those moments are threatened if a scientist tells us how to size up a person with an equation.

What I learned this semester is that people are defensive about science explaining our personalities, our selves. But what I also learned is that no matter how hard it tries, science cannot explain even the average Joe’s behavior or personality with genes or otherwise.

So what’s the big deal? Relax. You’ll always be somewhat of an enigma. And so will I.

Here’s me lifting my arms behind my head, leaning back, grinning, and sighing contently.

School’s Out!


Anne Buchanan said...

Nice post, Holly! Sounds like it was a good class -- you certainly got down to the complexity of the issue!

I especially like this part:

"Problem number three has to do with normal versus abnormal behavior. People seem to think that because a behavioral disorder can be traced back to genes, then therefore variation in that behavior at the normal level in unaffected people can also be explained by genes."

True of many complex traits.

Holly Dunsworth said...

I don't know how I got through that whole post without using the word "complex."

Anne Buchanan said...

Classic example of "show, don't tell".

Holly Dunsworth said...

Also, HTML hates me this morning. Under the stuttering topic it should say: "Plus, there are some people in the sample of non-stutterers (albeit a very few, <0.5%) who have the alleles that stutterers do."

Ken Weiss said...

Great post! Complexity becomes more complex every day, whatever word one uses for it!

Holly Dunsworth said...

I want to thank my students for such a fun, funny, inspiring and illuminating semester!