Oh…I was getting you confused with Mosier. Sorry about that.
But in a more general sense, the problems with this paper are the same that I see pervading much of the field: assuming facts not in evidence (e.g., that behavioral trait X is an adaptive response), then concocting experiments which may well illustrate a larger principle, but do not logically permit the more specific conclusion.
I’m not an Adaptationist (don’t yell at me - it’s a school of thought within evolution theory), so I disagree with many of the current methods and conclusions of EP on principle. If they took the added step to demonstrate adaptation (the “how”), then I’d be more inclined to pay attention to their proposed “why”. None of the EP papers that I have read have even acknowledged possibilities such as emergent phenomena, which one would think they’d be all over as a field, if they weren’t so stuck in the Adaptationist way of thinking.
I have read of similar studies with monkeys and their fear of snakes. The conclusion IIRC was that the monkeys could be conditioned to fear lots of strange things but it took a lot less conditioning to make them fear snake-like things.
It’still not proof that its an evolved response of course but I found it pretty compelling…which, FWIW, sums up my attitude to much of EP. It’s pretty compelling but I am not yet completely convinced. I find it more compelling than most of the alternatives that I know about though.
Claiming that the lack of a correlation of single genes with singular behavioural traits disproves EP is about as silly as claiming that the nonexistence of a leg-gene or a colon-gene proves that physiology isn’t due to genetics. Both behaviours and organs are high level characteristics of an organism, behaviours arguably much more so, and to find them encoded in single genes would have to be considered an enormous fluke – not in the least because any mutation on such a gene would likely be immediately devastating for the organism.
In any case, I’ve asked you this before – do you believe that genes don’t affect behaviour at all? If that’s the case, do you think your biochemistry plays a role in determining your behaviour, or not? And do you think that your biochemistry is in turn influenced by your genes?
For instance, dopamine levels appear strongly correlated with religious belief, and I don’t think it’s a stretch to tie dopamine production to genetics; in a hypothetical environment were atheists (or believers, take your pick) were routinely killed by whatever measures, is it that inconceivable that a higher (or lower) dopamine production would be an advantageous trait, and thus be selected for?
Be all that as it may, this serves nicely to highlight the problems with EP as I see them – it’s basic claim, that psychological traits may be or often are adaptations, is almost trivially true; however, to actually figure out the relevant connections in a scientifically meaningful and testable manner (rather than just speculating about more or less plausible evolutionary pathways) may be close to impossible.
For once, I have to agree with Der Trihs: Evolutionary psychology goes against the reigning blank-slate orthodoxy, and All Right-Thinking People are indignant about that.
Well, the main claim is innate spider detection, not innate fear, and they showed that infants react to a spider shape differently from other otherwise comparable stimuli. The hypothetical, but reasonable, explanation of why we should have such a mechanism is that it was adaptive for our ancestors to recognize and avoid spiders. I suppose we might have evolved innate spider detectors for other reasons, maybe because our ancestors liked to eat spiders, but it does not seem very likely, especially in light of the fact that arachnophobia seems to be quite common.
Seriously, how many cultures have spiders as a significant portion of their diet?
They could have looked for signs of innate fanged monster detection as well, but that would have been a different experiment on a different, though related, topic. Are you thinking that they should have been looking for evidence for an innate scary thing detector? I am pretty confident that that would have been a waste of time.
Some of the stuff being talked about isn’t really EP is it? It’s just basic sexual strategy. You can observe this stuff in animals and make nice diagrams. EP comes in with the weird whys. Something like, women have large breasts compared to other mammals because it’s supposed to replicate the posterior like in apes. Or men don’t have a bone in their penis because women want to see how healthy they are. Stuff like that. Good luck proving that either way. Or maybe I’m wrong.
“Basic sexual strategy” is part of EP - if you are willing to admit that sexual strategy has an instinctive component in humans. Quite a few people aren’t; it’s all culture according to them.
Don’t know much about EP myself, but I think this is a big part of why it gets a bum rap in the outside perception of it; a lot of it comes across as just speculating. From the outside it looks like: construct a plausible-sounding (though not necessarily verifiable) back-story for behaviours observed today and you’re set. It can seem hard to distinguish why the nutty-sounding explanations have less evidence for them than the sensible/probably-how-things-really-happened ones, which contributes to this perception of the field as a whole.
One point that hasn’t fully been explored in this thread is the circular nature inherent to EP “research” - a problem faced by historians also.
Based on the current state of human behavior, we can speculate on past evolutionary pressures. The only way we can confirm these speculations (since we can’t look at the past) is to examine current human behavior. The theories about what caused one behavior don’t give us any new knowledge, or even suggest other behaviors to examine.
Not many hunter-gatherers now exist in places where there are also large spiders. I’m pretty confident that where they do, a very large portion eat them - since hunter-gathers rarely pass over a possible food source.
I know for a fact that at least certain ones in the Amazon do.
Looking at it rationally, spiders were simply not significant to people in any way that ought to be detectible from an evolutionary perspective.
Some people eat 'em, most people fear 'em, but they were neither a significant food source nor a particular menace to humans. Sure, some species (very few, relatively) are and were poisionous, but actual deaths or injuries from spider-bite are, and almost certainly were, a statistically trivial source of human injury or mortality.
In terms of evolutionary encoded behaviour, fear of spiders simply doesn’t make any great sense. The fact that it is wide-spread is simply puzzling. Arguing that it must have an evolutionary basis because it is wide-spread smacks of cirrcular reasoning (and in any event, merely being wide-spread isn’t enough - for it to have an evolutionary basis, it would have to be universal, since Amazonian hunter-gatherers did not evolve from a different species).
In summary, a spider phobia is a strange behaviour to attribute to evolution, since possessing one would, rationally, confer little to no evolutionary advantage and since evidence suggests that individuals brought up in at least some different cultures do not possess it.
That’s another fallacy that a lot of people fall for. They think that explaining why something happens is the same thing as justifying or excusing it. We saw that after 9/11- a lot of people seemed to think that trying to figure out why terrorists attacked us was somehow saying that the terrorists were right to do so.
Of course, it can be a bad feeling to look at an evil thing that someone has done and understand why they did it. You might have to think “in some circumstances, I might have done something like that”. Not a comfortable thought. It feels better to think that people who do evil things do them for no reason that could ever be comprehensible to a non-evil person.
I agree with most of the rest of your post, but this bit doesn’t seem quite right – there are lots of traits that have an evolutionary basis and nevertheless aren’t universal, as part of the normal genetic variation within a species; think melanin production/skin colour, for one. It would be perfectly plausible for one population of humans that share their environment with lots of deadly, aggressive spiders to evolve an anti-spider sense if there were a significant reproduction advantage to be gained from this, while such a thing never develops in other populations; indeed, if a population were to split off from the spider-fearing one and migrated into a different environment without spiders, it’d be perfectly possible for them to lose their spider fear through normal genetic drift.
However, I agree that spiders probably never were enough of a factor in early human reproductive success to influence genome viability, so this is more of a nitpick really.
Heh, I suppose so. Though if there were any evolutionary basis for spider-hatred, any your correction was accurate, one would expect it would be strongest where poisionous spiders were more common. For example,spider-phobia appears quite strong among those of european ancestry, where (as far as I know) poisionous spiders are pretty rare. Of course, the ancestors of europeans may have evolved in places where such spiders were common, I suppose. But such a deep history would point to a behaviour much more ancient, and thus more universal, than variations such as skin colour.
Again, we agree that poisionous spiders probably weren’t a big evolutionary factor no matter what.
With respect, I think you may be making a common mistake here - assuming that evolution selects for the “most fit” outcome - that is, for changes that confer outright benefits. That isn’t so. It’s more accurate to state the evolution selects for the “least unfit” outcome - features which don’t confer any particular benefit are perfectly capable of persisting indefinitely when they aren’t actively harmful. A moderate instinctive fear of spiders wouldn’t be particularly beneficial - as you correctly note, spiders just aren’t that dangerous - but nor is it particularly harmful (spiders aren’t that useful). I’m not saying that fear of spiders is an instinctive, genetic behavior - the Amazon example seems to suggest otherwise, though I note people can overcome instinctive behavior - but it’s possible that it occurred as a fluke, and persisted because it’s a neutral adaptive trait. It neither helps nor harms us.
It’s also possible that an instinctive fear of spiders might be part of a more generalized instinct that does confer a survival benefit. For example, an aversion to unfamiliar animals could easily confer a significant survival benefit. Humans in groups can take down just about any animal with simple tools - but an individual human is vulnerable, and tasty with ketchup. A fear of animals that you lack sufficient familiarity with to know that they’re harmless could keep a migratory animal like homo sapiens alive when entering a new environment.
It is possible I suppose, but it strikes me that a theory that proposes behaviours have a “genetic” basis where the behaviour neither harms nor helps much, seemingly isn’t present in everyone, could occur as a “fluke” or be part of a “more generalized instinct”, etc. is a theory exceedingly hard to test.
This is, in a nutshell, the problem with the discipline. Sure, everyone (okay, everyone who isn’t anti-science) is well aware that humans, like any other animals, have evolved. It thus sounds plausible that anything humans do must be part of behaviour which has also evolved. Problem is that human behaviour is so malliable and variable that pointing to any particular aspect of human behaviour and claiming it is an example runs into serious trouble. It is difficult to isolate any one thing that humans do and say “we evolved to do it this particular way” without a lot of social anthropologists pointing out that, in fact, some humans do it differently. Of course people can go against their evolved instincts so that doesn’t falsify it … problem is, I can’t immediately think of anything that would.
To my mind, what has “evolved” are some pretty basic drives; how these are expressed in actual human behaviour is complex and context-specific. Thus, the insights gained from evolutionary psychology may not be very universal, predictive or useful. I cannot say that they are not correct because they may be unfalsifiable.
I don’t see it as reasonable at all, really. What do we have to fear from spiders, exactly, that would warrant an evolutionary need to recognize them at 5 months of age? It’s not like early man had to contend daily with man-eating spiders. Or even man-biting spiders, in all probability. That, and the whole point of the exercise was, as the authors state, “Has evolution provided humans with a means to identify these animals so that a fear response for them can be quickly acquired?” They are attempting to derive an evolutionary explanation for “fear of spiders” without having established that such even exists.
And how do we know that the spiders/spider-like images are recognized at all? The authors interpret the extended period of “look time” as “recognition”, when it could very well be the opposite: the infant is taking longer to examine the image because it’s trying to work out just what the heck that is. Or maybe it’s just an interesting image… Neither of these possibilities were considered in the study.
I am saying that I am dubious that infants possess an innate, spider-specific recognition ability, and may instead possess a more general “weird-looking thing” recognition ability. The authors only tested spiders and flowers, while leaving out a whole host of other possibilities which would be necessary to conclude anything at all about their actual claim.
On the contrary, I believe you are making the common mistake of assuming that natural selection only serves to weed out the negative. Natural selection is the primary constructive force in evolution; individuals who possess beneficial variations are preferentially selected for, while those possessing detrimental variations are preferentially selected against. Were it otherwise, beneficial traits would not lead to adaptations, as they would be no better than “average” traits.
Which is one of my points with reference to the spider study: showing that infants allegedly recognize spiders says nothing about whether this is a general or specific recognition, and the authors did not expand their experiment to determine whether that might be the case. It is flawed because the authors had a predetermined outcome in mind, and only tested with respect to that outcome. This is a problem that seems to be endemic to the field, really.
I believe it is because starting about 25,000 years ago, some psychologists showed an ability to see accurately into the past. These reverse soothsayers ended up more successful than their more empirical minded counterparts because women love a man who can remember what she said. Popular science (non)fiction became the driving force behind evolution. These pregnosticators were the most fit to survive in the world of water cooler scientific literature, much to the chagrin of ivory tower lab-based academics. So here we are today.
Nevertheless, we have found genes that are relevant to the construction of organs. Even if there were ten or twenty or a hundred genes that participated in shaping a behavior module, there would still be a correlation between certain genes and the resulting behaviors. The correlation might be small, but it’s possible to sniff out a small correlation by doing a large study. That’s exactly the approach taken by Robert Plomin’s study attempting to find the genes that govern intelligence. The study involved thousands of children, yet it still failed to find a single gene with a strong correlation to intelligence. (It found a few genes with weak correlations, none strong enough to be certain of statistical significance.)
“Behavior” is a category so broad that I can’t really answer this question. Obviously some things we do are innate; breathing comes to find. Other things that we do are entirely subject to our will, such as deciding what to post on the Straight Dope Message Board. Somewhere between the two there’s a fuzzy, gray area containing behaviors that are somewhat influenced by our innate make-up but which can also be subjected to the will. It seems likely to me that there is some innate mechanism which causes us to experience sexual attraction. On the other hand, the evolutionary psychologists who insist that our genes force us to desire a certain number of mates, or to prefer certain hair colors in our mates, or to prefer certain heights in our mates, or to desire mating at a certain time of days, or so forth, are obviously wrong. One need only observe how much human mating preferences vary from one place to the next, from one time to the next, from one individual to the next, and even within one individual, to see that these things are not guided by our genes.
And that’s a classic demonstration of why evolutionary psychology gets such a bum rap. The majority of men (in Britain at least) do not think that it makes sense to cheat on their wives or girlfriends. Therefore any theory that sets out to explain why men do cheat is already off on the wrong foot. In reality, of course, most men believe in monogamy because that what we’re taught in our society. In societies where polygyny gets taught, most men believe in polygyny. Lastly, even when men do cheat, how many of them are cheating because they want to “promote” their genes? Most male cheaters would want to avoid a pregnancy with their extra-marital partners.
The claim that women “wait for the best possible set of genes” is equally easy to tear down. There’s no agreement among women about which man is most desirable as a husband; instead, each women chooses a different husband. Therefore there’s obviously not a single best set of genes, from the female perspective. Rather, it seems that the highly individual process of falling in love is the driving force here. Once again, just ask how many people you know who actually choose partners or choose to have sex based on the chances of propagating their genes.
But let’s grant for the sake of argument that people do make these choices based only on the desire to propagate their genes, and that there’s some possible mechanism by which genes could influence people’s sexual decisions. Even with that granted, the classic evo psych answer still doesn’t make sense. Suppose a man did have a genome which forced him to prefer sleeping around with as many women as possible. If he did so, most of the time it wouldn’t help his genes one bit. First of all, women only ovulate during four days out of every thirty, so most sexual encounters don’t even result in conception. Second, when conception occurs, two thirds of all zygotes never actually reach birth. Third, in primitive societies about half of all babies died in infancy. So a bit of basic math tells us that only 2% or so of sexual encounters actually lead to viable offspring. The ‘spread your seed’ approach to reproduction would not actually help a man to propagate his genes much.