One of the hottest debates in evolutionary biology concerns the origin of behavior: is it genetically encoded or do animals and birds copy their parents or other individuals? A classic experiment published in 2000 seemed to provide overwhelming evidence that a particular behavioral choice (whether individuals of a species of swallow breed in a small colony or a large one) is largely genetically determined. Scientists have now re-examined the data and shown that the findings could be explained by random choice.
via The importance of (experimental) design — ScienceDaily.
A shot across the bow for evolutionary psychology? One of the hardest things about behavioral sciences is sussing out genetic behavior from learned behavior. This study apparently just added a new wrinkle to take into account when looking at behavior. It’s about animal behavior, but I suspect there are implications for human studies as well.
It seems like these kinds of studies are getting progressively more expensive. Human studies now need to be cross cultural to avoid WEIRD (western, educated, industrial, rich, democratic) biases. Now they’ll have to look out for these identified fallacies.
13 thoughts on “The importance of (experimental) design — ScienceDaily”
It’d be nice if they could do something about the pattern of stupid news articles on evopsych research. No more Just-So stories!
I think avoiding just-so stories is first on the agenda of most quality evolutionary psychology work. Unfortunately, not everything that makes news is the quality stuff.
It seems, there is a tendency among evolution scientists to believe that every trait of living species exists because it must have some advantages to survival. I don’t understand why. I can see several cases for how new traits may develop:
1. A trait or behavior gives individuals having it advantages for survival over individuals that don’t have this trait or behavior. Such trait may become dominant through natural selection.
2. A trait or behavior has a disadvantage for survival in certain conditions and it may disappear over time because of extinction or it may still be seen, but in a disappearing minority of the population or in an isolated population which is not exposed to these conditions.
3. A trait or behavior does not affect survival whatsoever, neither promoting survival, nor leading to extinction. I believe, the trait may still become dominant through propagation among individuals of the species through either genetic or “memetic” (learning) mechanisms.
This third possibility came to my mind when somebody asked why humans cry (shed tears from the tear glands) as a result of strong emotion. I couldn’t find any advantages for survival in this behavior, but there seems to be no reason why this behavior would lead to extinction. It often seems to me that scientists are looking for a black cat in a dark room when they try to explain animal behavior. A lot of stuff is done “for no particular reason” as Forrest Gump used to say.
Supposedly most changes aren’t selected for – they just show up as random mutations and carry over as long as nothing selects against them in terms of the environment. Biologist PZ Myers has a long piece on it over at one of his blogs. If you scroll down, there’s a helpful, readable chart too.
PZ Myers appears to be capable of generating coherent sentences when he is not using profanity towards religion.
Two interesting observations. Proposition that
is recognized as false.
I think, humans consider themselves to be a “crown” of evolution out of conceit. Humans are not the acme of evolution. Rice has nearly twice as many genes as humans. That seems to make rice more “evolved” and “complex” than humans. Due to the large brain, humans show a huge variety of adaptive behaviors. But human bodies don’t seem to be very adaptive. Any plant adapts to environment in much more sophisticated ways than humans.
Neither are humans best at survival. There are bacteria and insects on Earth that have survived virtually unchanged for millions of years. I bet, these bacteria may still be around after humans wipe themselves out with a nuclear or environmental disaster of some sort. There are individual plants that live longer than humans have been around on Earth. Complexity does not necessarily mean fitness for survival. It often means the opposite. Complex machines break more easily.
Besides, I cannot wrap my mind around how “random choice” fits into the “determinism/free will” worldview. Do swallows “choose” where to live? Or do they just happen to live where they do? Or is their behavior determined by genetics? Then, are the genes determined by something else or do they “happen” to be what they are? Why is this so important to explain and understand?
Can somebody explain to me why humans are so obsessed with explanations?
Explain your desire to understand that 🙂
I think, it’s self-explanatory and does not need an explanation. “God made it that way” or “it happens to be that way” or “humans are obsessed with explanations due to random mutations of their genome” or, simply “I don’t know why and there is no way to know” — there are many ways to convey the same meaning. Does it make me intellectually lazy and incurious?
PZ Myers’s pretended “explanation”
seems to be just another tautology.
I’ve often noticed over the years that I sometimes become interested in something for no reason that I can name, only that I’m interested in it. I have no idea if it arises out of some adaptive urge, a subconscious calculation, or some spandrel instinct. But I’m very aware of the feeling. So I know where you’re coming from.
Yes. I sometimes say “what makes sense does not require an explanation”.
Reblogged this on Lev Janashvili and commented:
My prediction: We will never be able to distinguish between learned and genetically determined behaviors, not with complete accuracy. We now know that genes are not what we once thought they were, just as atoms are not the indivisible solids we once thought they were. These are the ultimate questions in and beyond science. We are looking at an infinite puzzle in which every discovery raises more questions than it answers.
I tend to think we can gain some important insights into genetic vs learned behavior, but I agree that we will probably never as much certainty with it as we’d like.
Agreed on the infinite puzzle. Turtles all the way down.
Ha. Turtles. I like that.