I tend to be slightly suspicious of evolutionary biology, especially evolutionary psychology. By which I don't mean that I doubt the veracity of the theory of evolution, but rather that I am suspicious of the claims of evolutionary biologists to have found hard and fast rules about human nature based on the inevitable necessities of natural selection. The stories often sound very convincing--but often I could make up an equally-plausible sounding story to prove the opposite. Unsurprisingly, the theories tend to confirm the researchers' prior beliefs about human nature.
For example, the fact that men have lots of sperm and women have few eggs is often advanced as the reason that men want multiple sexual partners, while women crave a stable relationship with one man. Men can be indiscriminate, relying on volume, while women have to husband their resources, choose carefully, and make sure he'll stick around to raise the offspring. This genetic hardwiring is why most female animals don't cheat.
Except, oops, they do. I could theorize that women have an incentive to find lots of fathers for their children, in order to ensure that she and her brood will still be taken care of if one of them dies in the rough Pleistocene lifestyle. There's no a priori reason to believe that this is any less plausible than the "men are genetically destined to prefer more sex than women"--except that we have a deep cultural belief that women don't want to have lots of sex, so therefore we "know" that evolution must have programmed them that way.
And maybe it's true. But I'd rather be a prostitute than eat another human being, and there's little evidence that evolution selects against cannibalism. Disentangling what's natural and what's programmed into us by our shared culture is really, really difficult.
That said, this is a pretty plausible, and certainly interesting, essay on how our attitudes towards various forms of dominance hierarchies may have evolved:
Well-structured societies today, including modern mass democracies, provide adequate outlets for our hunter-gatherer preferences to fit into hierarchies, to achieve relative dominance in them and to possess personal autonomy, all at the same time. The variety of independent spheres of life today opens greater possibilities than the Pleistocene did for individuals to fit in, to lead and to follow in organised groups.
As for hierarchies and elitism, our intrinsic resentment of leaders, our Pleistocene anti-elitism, may partly be explained by the fact that small-scale tribal societies were zero-sum economies. Everything that was owned by one person was something that someone else could not enjoy. Some psychologists argue that the zero-sum nature of the Pleistocene gives us a psychology that has a lot of trouble grasping concepts of borrowing, interest and economic growth.
In the Pleistocene, people had a very poor notion of inheritance because mobile bands could not acquire land or much in the way of possessions to pass on to children. Inheritance became possible only when cities were established, along with systems of kingship and ways for power and property to be passed through dynasties. There were no dynasties in the Pleistocene.
The Pleistocene mentality tends to regard anyone who gets rich as having done so at the expense of someone else. When it comes to the benefits of free trade, for instance, this kind of thinking makes us hard-wired protectionists. Our intuitions favour basic Pleistocene-style exchanges, but modern economies involve much more than that, with processes such as interest and investment that we don't always understand.
It makes intuitive sense to me--this may be why (bad) arguments in favor of protectionism are an easier sell than (good) arguments in favor of free trade. But still, my doubt remains . . .
I thought male promiscuity was a genetic response to evolutionary forces that, tautologically, favored the genes of people who had the most children. Thus, men are driven to impregnate women left and right. But this theory should also suggest an evolutionary predisposition to female promiscuity too. Not clear to me why that didn't work out...
I think it's less complicated than this. In the Pleistocene era, surely there was some degree of tribalism? Fear of "the other" and protection of the home is a pretty basic instinct. Trade inevitably leads to people -- "our" people -- losing jobs to "outsiders."
So I guess in the sense you could say we're predispositioned to a zero-sum mentality, but I don't think there's anything like a "zero-sum mentality gene." Just fear, which after all is a pretty useful instinct in many cases.
John,
If I recall my reading correctly, the infidelity pattern for women is to marry a nice, stable provider who makes a good husband and father for day to day to living; and then to cheat with a hunky attractive fellow who will pass on his hunky attractive genes to her offspring.
Actually, evolutionary psychologists do recognize that women are promiscuous as well. The theory goes that women want to marry the guy who is most likely to raise her children well, but want to have sex with those who are more attractive (where physical beauty is a proxy for genetic fitness). So they get the best of both worlds - good genes for their children, and a good father to raise them up.
Actually, ev-psych does explain female cheating. A female doesn't need the father of her offspring to stick around and provide for them--she needs a male to stick around and provide for them.
The optimal strategy, if you can pull it off, is to cheat with the male who has the best genes, and then trick your mate into providing for the resulting offspring.
"Marrying" the male with the best genes is good, too, but it's not always feasible. When an alpha male can acquire enough resources to support the offspring of many females, you get a harem system. But when that's not possible, a male can only support one or a few mates, and the other females have to cheat if they want both his genes and support.
This was understood at least as early as 1993 (I learned about this from Matt Ridley's The Red Queen), and probably long before that (since it usually takes a while for cutting edge science to filter down to the popular media), so the linked article's assertion that biologists didn't know about female promiscuity prior to 2000 is probably wrong.
Note also that sexual behavior varies widely from species to species based on a number of different factors. As I mentioned before, some species have harems, and others don't. If the males of a species have evolved a way to detect cheating, females are less likely to do so. As in economics, incentives matter, albeit only instinctually.
I must admit that I do find the idea that lefties are locked into a stone-age mentality quite appealing, though.
Megan,
Your description of the evolutionary psychological theory of parental investment is a gross oversimplification, and your idea that it predicts that females won't ever cheat on their mates is simply false. This kind of poor understanding of evolutionary psychology seems to be common among its critics. There is overwhelming evidence that men tend to be more sexually promiscuous than women, and that this difference is substantially determined by the different biological roles men and women play in reproduction. The theory is supported by many independent lines of evidence from anthropology, sociology, zoology, genetics and other fields.
Likewise, your claim that EP theories "tend to confirm the researchers' prior beliefs about human nature" is highly dubious, not least because many leading researchers in the field are women and/or politically liberal.
You also repeat the silly claim that EP explanations of human behavior are mere "stories" (at least you didn't say "just-so stories"). EP is an established and growing field within evolutionary biology, and EP explanations are testable scientific theories supported by empirical evidence and published in prestigious scientific journals.
"But I'd rather be a prostitute than eat another human being, and there's little evidence that evolution selects against cannibalism."
I dunno, when other mammals exhibit cannibalism it's usually only in specific cases. A male bear will kill the cubs of a female bear so she'll go into heat again. He typically doesn't eat the cubs when this happens. If he kills the mother bear in the process then he'll sometimes eat the remains, but usually very slowly. Chimps only practice cannibalism when they kill others from a rival clan.
The reasoning behind evolutionary biology is that if multiple animals exhibit a behavior then there is likely an evolutionary reason why.
And equally reputable and prestigious scientists have called EP precisely that - "just-so stories." The problem comes in a lack of principled constraints on the range and kind of behavioral traits that EP claims to be able to explain, and a lack of principled constraints on the range and kind of potential evolutionary-historical factors that are viewed as being able to shape behavior in such a way as to impact reproductive fitness. Essentially, the theory of EP is just too powerful, in the technical sense. A theory that can explain everything is a theory that explains essentially nothing (cf. "God did it").
This ignores the problem of specifying the purported Pleistocene environment, and the assumption that behaviorally relevant changes to the human genome have not happened within historical time, despite growing evidence to the contrary. North European tolerance for lactose is just the best known example of the later problem.
Megan made a good point - for almost any EP explanation, one can come up with an equally plausible account of why the opposite should be true. The theory gives you no a priori expectations about what sorts of things should be true about the world, and thus has very little explanatory power. Plenty of people who author articles in those "prestigious scientific journals" have made this observation.
I thought male promiscuity was a genetic response to evolutionary forces that, tautologically, favored the genes of people who had the most children. Thus, men are driven to impregnate women left and right. But this theory should also suggest an evolutionary predisposition to female promiscuity too. Not clear to me why that didn't work out...
It has to do with the minimum investment of each sex in reproduction. Men's minimum investment is a few minutes of sexual activity and a small amount of semen (of which the supply is essentially unlimited). Women's minimum investment is one of a very limited supply of eggs, nine months of pregnancy, and breastfeeding. This means that the optimum reproductive strategy for men emphasizes the number of sexual partners, while the optimum reproductive strategy for women emphasizes quality of sexual partners. Now, there are lots of caveats and qualifications to this. Women do have some incentives to promiscuity, and men do have some incentives to be discriminating. The optimum stategy for particular individuals will also depend significantly on the social and natural environment in which they live. But the basic pattern of male promiscuity and female choosiness is fundamentally determined by the biological investment each sex makes in producing and raising offspring.
So the next time someone comes along proposing economic justice through wealth-leveling redistribution, we get to call them a bunch of cave men. Sounds fair to me.
At any rate, IMO zero-sum has a much simpler explanation at hand:
1. It is easier for a rich man to steal his way to wealth than to create wealth.
2. It is easier for a poor man to envy those riches than to admire the one who acquired them.
Combine prejudice (2) against wealth acretion with reinforcing evidence from cases where the rich man actually did (1), and very soon, any one richer than me can be assumed to have gotten it by taking it from me, which then becomes a convenient justification for finding means of "taking it back".
Thus, zero-sum allows me to minimize any flaws in my own state that prevent me from being richer, and simultaneously minimizing any virtue in the rich man, and then justify remedies that allow me to become richer without doing any actual work for it. This mode of thinking is popular for obvious reasons.
JAR,
The problem comes in a lack of principled constraints on the range and kind of behavioral traits that EP claims to be able to explain, and a lack of principled constraints on the range and kind of potential evolutionary-historical factors that are viewed as being able to shape behavior in such a way as to impact reproductive fitness.
Well, don't keep us in suspense. What unjustified explanations of human behavior do you assert evolutionary psychologists have made, and where have they made them? I'm looking for proper citations to actual EP research, not unsubstantiated assertions.
This ignores the problem of specifying the purported Pleistocene environment, and the assumption that behaviorally relevant changes to the human genome have not happened within historical time, despite growing evidence to the contrary. North European tolerance for lactose is just the best known example of the later problem.
I don't know what "the problem of specifying the purported Pleistocene environment" is supposed to mean. This statement is typical of the kind of vague allusion to alleged problems that I see all the time from critics of EP. Your claim that EP assumes that no behaviorally-relevant genetic changes have occurred in historical time is simply false. Again, this kind of misrepresentation of EP is common among its critics.
Megan made a good point - for almost any EP explanation, one can come up with an equally plausible account of why the opposite should be true.
No, one can't. EP explanations are testable scientific theories supported by observation and experiment. If you really believe they are just "stories" to explain behavior for which there are "equally plausible" alternative stories, perhaps you could give us some concrete examples, with citations to the EP researchers and papers in which these alleged stories have been told.
You're mistaken about the theory about sperm vs. eggs. That isn't the explanation for why men cheat; it is the explanation for why men are *promiscuous*. And it isn't eggs, it is the cost of pregnancy. Biologically speaking, pregnancy costs men nothing and costs women nine months of fertility and a lot of inconvenience. The theory is that this is why women overwhelmingly focus on finding a "good provider", i.e. a man who is wealthier and more successful than they are, while men will pretty much stick it in anything that wiggles.
One other thing:
But I'd rather be a prostitute than eat another human being, and there's little evidence that evolution selects against cannibalism.
That's just an odd thing to say, in my opinion. There's a mountain of evidence that evolution selects against cannibalism. Most animal species avoid cannibalism except in extreme circumstances.
Mixner, I'd say there's a danger of printing our cultural norms onto animals. We don't know how a male bird feels about raising offspring that aren't his. You're essentially telling a very common human story about a bird cheating on her mate to fool him into raising her bastards, when the terms "cheating", "promiscuity", "mate", and "bastards" can't have any meaning for a bird.
Calling it a story is not perjorative; that's what all human interpretation is. A realistic model of the universe is . . . the universe. Anything simpler requires that we sort out what facts are relevant, and turn them into a coherent narrative. The problem is that our prior beliefs strongly influence the facts we pick out to put in our narrative--a theory that is far better documented and tested than any evolutionary psychology theory I've ever seen.
I have great respect for science. But I am also familiar with enough philosophy of science, history of science, and sociology of science to know how many times scientific communities have developed and maintained erroneous beliefs in the face of what now looks like overwhelming evidence to the contrary. It's the human condition.
No, many mammals avoid cannibalism except in extremis. The animal kingdom is mostly insects and fish, who happily chow down on their brethren all the time. And eating your enemies is not only common among chimps, but among human cultures; I would still much, much, much, much, much rather turn a trick than eat Eliot Spitzer.
Megan,
Mixner, I'd say there's a danger of printing our cultural norms onto animals. We don't know how a male bird feels about raising offspring that aren't his. You're essentially telling a very common human story about a bird cheating on her mate to fool him into raising her bastards, when the terms "cheating", "promiscuity", "mate", and "bastards" can't have any meaning for a bird.
We don't have to know "how a male bird feels about raising offspring that aren't his." Parental investment theory is testable in the same way as any other scientific theory, through observation and experiment. The theory that the less-investing sex will more promiscuous, and the more-investing sex will be more discriminating, has been confirmed through observations of thousands of animal species, including the rare species in which males invest more than females and their patterns of sexual behavior are likewise reversed, as the theory predicts. As I said, we also have evidence from genetics, anatomy, anthropology and other disciplines.
By the way, Robert Trivers, the biologist who devised much of the foundational theory of EP in the 1960s and 1970s (parental investment, reciprocal altruism, parent-offspring conflict, and others) was awarded the Crafoord Prize last year for his work. The Crafoord is the equivalent of the Nobel Prize for the biosciences.
It would be difficult to make a case that women have been historically promiscuous (at any kind of rate approximating male behavior). The reasoning behind it? The same reason that women didn't hold jobs (or any job they wanted) outside the home. The same reason that women were not off sailing ships to new worlds or slaying Incas. The same reason they were not leading Mongol hordes or holding up swords saying, "I am Spartacus" while in the tub with Tony Curtis.
MEN WOULD NOT LET THEM. So in theory a woman may have wanted to screw around, but wanting to, and doing it, are two different things. A woman would likely have gotten stoned or beaten. Or put out of the camp. Or set on fire. Or cast aside and forced into poverty (and often involuntary prostitution).
We can assume, looking at the evolution of law and women's rights, that women are progressively freer now than before. Generally, despite whatever was going on in the brain, they were not quite so free to explore the libido or alternate partners as they can now. Hard to do so from inside the hut of your spouse's family.
The biological difference then, male physical strength (inspired by testosterone), was far more a factor in life because technology (among other things) had not yet raised its powerful voice.
If we evolve the world backwards, the cost for promiscuity was too high, and the opportunity was harder to obtain.
Only with the advent of technology (combined with moral/ethical/legal arguments and a few other factors) have women truly been able to offset the restrictions of male dominance.
I think the outward evidence of women being promiscuous historically is scant, and wishful thinking, and the inward level is an unknowable factor, the path not allowed to be taken.
The question then becomes, "Free of contraints, are women inclinded to be promiscuous at the same rate as men, on average?" If you can calculate modern rates for the sexes, one can hardly work backwards in time toward higher rates than are now evident.
Women like the theory of the sexually liberated woman, and despite all historical written evidence that men back then were more likely to beat the daylights out of you for drifting, some are nevertheless suggesting that the threat of force (and biology) played no factor.
Is the desire for promiscuity that you head in your head for thousands of human years, largely unexpressed, a stand in for actually being promiscuous? Or maybe men back then were far less possessive, watching their women drift off to screw some philistine or neanderthal? Sex in the Prehistoric City? Yea I'm sure.
In reality, men saught sex because they could get away with it, and women did not seek the sex because they could not get away with it, and biology was the control agent. And the external biological factor eventually becomes internalized.
Apart of course, Mixner, from the actual Nobel Prize for Neuroscience, which I usually reckon to be a bioscience, though that may be professional pride talking.
For an off-the-cuff example of an expansion of EP that is particularly problematic, I could cite the handicap principle of Zahavi and Zahavi, which if you are familiar with the literature, you will be aware of. The basic idea is plausible enough, and no doubt, in some particular cases, true - one signals greater genetic fitness by an outwardly unhelpful or even harmful behavior/trait/whatever. This is problematic simply from the perspective of the lack of constraints on the hypothesis space that I discussed earlier - what, precisely, keeps me from taking any unproductive or apparently harmful behavior and accomodating it by reference to the handicap principle?
Understand that my objection to EP is rooted mostly in the philosophy of science/conceptual level, rather than the empirical one. EP is simply not an explanatory theory in the same way that, say, mechanical physics is an explanatory theory. The integration of insights from something resembling game theory into the detailed natural history that has always made up the bulk of evolutionary biology is commendable. But that's really as far as I see its contribution going.
As for papers, a good one to start with is this galley proof from Jerry Fodor. Once again, if you are even vaguely familiar with the actual cognitive neuroscience/psychology/philosophy of mind literature, he is a name you SHOULD know. The paper can be found here: http://ruccs.rutgers.edu/faculty/Fodor/Fodor_Against_Darwinism.pdf
Note that he in no way rejects the basic Darwinian notions of the common origin of species or natural selection; his point (and mine) is much more sophisticated than that.
As a final note, I'm not sure that you really want to cite the winning of prizes as proof of the veracity or utility of a particular theory. Let us remember that the man who pioneered the frontal lobotomy won a Nobel Prize.
Megan,
The problem with people's perception of evolutionary biology and evopsych is that people (including you occasionally) think that the discipline is structured such that it should produce hard and fast rules. Living things are incredibly stochastic but we can use models to predict central tendencies. A lot of sperm vs few eggs is an input for relatively pursuasive models that then as a result suggest that men, on average, will prefer more partners.
Much of the time it boils down to relatively simple games and their nash equilibria. Of which you've demonstrated a clear understanding in the past. I'm not sure why these equilibria would be all that unintuitive for someone with your background.
Finn,
Males tend to be bigger and stronger than females because they want more sexual partners. Intense competition between males for sexual access to females creates an arms race between males. Bigger and stronger males tend to outcompete smaller and weaker ones for access to females, and thereby leave more offspring. Human culture institutionalized the social effects of this sexual dimorphism in patriarchal societies, but the biology came first, not the culture.
I realize I overlooked one of your questions that was fairly specific, Mixner, so I'll try and address it. What I mean by the problem of "specifying the Pleistocene environment" is really precisely that - having a particular good notion that is -independent of evolutionary psychology- of what the environmental and social challenges facing our ancestors might have looked like. Given how often people like Tooby and Cosmides return to this environment as an explanation in their work, I do not think this is a mischaracterization of the stance of an awful lot of EP folks.
It's certainly the case that the work in the general EP framework done by biologists as such ends up being substantially more rigorous than the EP work done by actual psychologists, but then, biologists are generally concerned with problems that are simpler, in the sense of being more easily defined. I actually believe that story re: differences in promiscuity between males and females, but there is a whole wide world of psychological phenomena out there beyond basic sexual behavior.
Give me a rigorous EP explanation of say, upward masking, or the A-not-B error, or, god forbid, recursive syntax, and I will eat one or more of my hats. There have been EP theories advanced of these sorts of things, and they are largely what has made me so very twitchy about evolutionary psychology.
The problem with people's perception of evolutionary biology and evopsych is that people (including you occasionally) think that the discipline is structured such that it should produce hard and fast rules. Living things are incredibly stochastic
If the goal is to have a philosophical discussion, then sure. But when confronted with the possibility that the stochastic nature of the subject raises legitimate questions regarding some of the cherrished foundations of the discipline, the practitioners are quite adamant that they are practicing science and dealing in facts.
"I would still much, much, much, much, much rather turn a trick than eat Eliot Spitzer"
Doesn't one imply the other?
JAR,
For an off-the-cuff example of an expansion of EP that is particularly problematic, I could cite the handicap principle of Zahavi and Zahavi, which if you are familiar with the literature, you will be aware of. The basic idea is plausible enough, and no doubt, in some particular cases, true - one signals greater genetic fitness by an outwardly unhelpful or even harmful behavior/trait/whatever. This is problematic simply from the perspective of the lack of constraints on the hypothesis space that I discussed earlier - what, precisely, keeps me from taking any unproductive or apparently harmful behavior and accomodating it by reference to the handicap principle?
The constraints of the scientific method. But the handicap principle isn't generally considered to be part of evolutionary psychology, anyway. It's a broader evolutionary idea that encompasses physical as well as psychological traits, so I don't understand why you raise it as a supposed problem of EP, let alone as an example of these alleged EP "just so stories."
Understand that my objection to EP is rooted mostly in the philosophy of science/conceptual level, rather than the empirical one. EP is simply not an explanatory theory in the same way that, say, mechanical physics is an explanatory theory. The integration of insights from something resembling game theory into the detailed natural history that has always made up the bulk of evolutionary biology is commendable. But that's really as far as I see its contribution going.
Again, it's hard to know what this is supposed to mean. Your criticisms of EP seem to be so vague and vacuous it's hard to give any clear sense to them. In what way is EP not an "explanatory theory?" Parental investment theory, for example, explains a variety of human and animal behaviors relating to sex, reproduction and the raising of offspring. It has generated numerous testable predictions that have been confirmed by observation and experiment of both human and animal species. I don't understand what you mean by saying it lacks "explanatory power."
What is it exactly that you are contesting? The basic principle that human and animal behavioral traits are shaped by evolutionary processes? Or just specific theories of EP? If the latter, what are those specific theories, and what specific aspects of them do you dispute, exactly?
Megan,
I'll join the chorus saying by saying model you're objecting to is vastly oversimplified and wouldn't be taken seriously as evolutionary psych anyway, so it's kind of moot.
I find EP interesting, but difficult to draw firm conclusions from, since the fossil record doesn't capture behavior as well as it does anatomy (also, not everybody working in it is doing a great job). The reasoning being applied to explain behavioral traits isn't fundamentally than how anatomical traits are approached; the "just-so story" critique can be applied to theories for the emergence of anatomical traits as well - the explaination that predators tend to have both eyes on the front of their heads because depth preception is more important to them is a just-so story as well. I disagree with JAR that EP is "too powerful" to be useful. EP doesn't excude as much as we'd like since it's often hard to empirically falsify or validate, but it still does require that there be a mechanism by which the observed behavior is adaptive which is consistent with observation.
Re: A female doesn't need the father of her offspring to stick around and provide for them--she needs a male to stick around and provide for them.
Why? We humans did not evolve in nuclear familes. We evolved in small, tight-knit bands of closely related individuals. Females did not need a single male at all: they had the resources and protection of the entire band, most of whom were their relatives.
Re: North European tolerance for lactose is just the best known example of the later problem.
Is this genetic or is it cultural/acquired? I have read that anyone who quits drinking milk and eating dairy products in adolescence will become lactose intolerant later in life, since the body quits making the enzyme (lactase?) if it's not needed. Cultures that kept dairy animals (mainly in Eurasia, but eventually in parts of Africa) may have kept their lactose-digestion abilities simply by virtue of the fact they continued to consume milk and its by-products in adulthood.
Re: This means that the optimum reproductive strategy for men emphasizes the number of sexual partners, while the optimum reproductive strategy for women emphasizes quality of sexual partners.
Female cats have fewer eggs than male cats have sperm, yet few creatures are more promsicuous than a female cat in heat. Her kittens in the same litter may often have different fathers.
Re: The animal kingdom is mostly insects and fish, who happily chow down on their brethren all the time.
Because these creatures repruduce with such abandon the main danger of cannibalism (consumming deadly species-specific parasites) is less an issue for them. Note that human tribes which practice cannibalism may pay a severe price: this is how kuru (related to "mad cow disease") is mainly spread in New Guinea, for example.
Re: Males tend to be bigger and stronger than females because they want more sexual partners. Intense competition between males for sexual access to females creates an arms race between males
Except that this is not how primitive human cultures operate. Males generally do not fight or even compete against each other for mates. Rather, mating is very often arranged by tribal elders (a pattern that persists even in fairly complex societies like India today). Open in-group competition between males would have been destructive to the social cohesion that humans needed (and still do need) to survive. It was avoided as much as possible, and societies today still strive mightily to damp down male violence. To be sure, males could (and still do) engage in violent behavior toeward males in other groups, and male strength came in handy when hunting large animals. But human evolution was never about the survival of individuals: it was about the survival of the group, without which the individual human would have been too weak to survive at all.
You're absolutely right about the just-so criticism applying to more than just EP, Matt. The paper I linked to makes this point far more eloquently than I could, since I am not one of the 20th century's preeminent American philosophers. Like you, I found EP accounts to be fascinating, but you've hit the nail on the head - evolutionary biology at its best can tell us what sort of traits -got selected-, without being able (at present even in principle), to tell us what traits -got selected for-. This idea of intentionality is a problem many biologists are loath to face, and that no amount of interesting correlational work can really overcome.
So even if a given behavior seems to have a large hereditary component, and even if one -can- conjure up a game theoretic explanation of why that behavior might have been advantageous and conducive to increased reproductive fitness once upon a time, you have still not demonstrated that the advantage to fitness -qua the advantage to fitness- afforded by the behavior is actually why it exists in the current generation of the species. It could simply be an inevitable consequence of the neural implementation of some other, otherwise unrelated behavioral trait, or could be the trivial consequence of an anatomical adaptation.
It's true that one requires a mechanism, but if you look at some of the wilder speculations about mechanisms that exist in the literature (like some of Massimo Piatelli-Palmarini's recent work), this is not a particularly strong constraint on theorizing.
I realize I overlooked one of your questions that was fairly specific, Mixner, so I'll try and address it. What I mean by the problem of "specifying the Pleistocene environment" is really precisely that - having a particular good notion that is -independent of evolutionary psychology- of what the environmental and social challenges facing our ancestors might have looked like.
Again, I think this just shows a fundamental misunderstanding of EP on your part. While we don't have detailed, comprehensive knowledge of our ancestral evolutionary environment, we certainly know enough about it to formulate basic theories regarding the influence of evolutionary processes on a variety of important human psychological traits. There were no towns or cities; humans lived in relatively small groups. There was little or no agriculture; almost all food was obtained by hunting and foraging. There was no modern medicine, no vaccines, no antibiotics; disease was common and infant mortality was high. There was no reliable contraception, and no infant formula; all babies were breastfed. That sort of thing. Our ancestors faced a variety of challenges relating to the acquisition of food, choice of mates, resolution of conflicts, avoidance of predators, and other problems that exerted significant selection pressures. We have abundant evidence for these basic premises about our ancestral environment, and EP researchers incorporate that knowledge into their theories. It's fundamentally the same process all evolutionary biologists use to formulate theories that depend on premises about ancestral environments.
"Mixner, I'd say there's a danger of printing our cultural norms onto animals."
I think you meant to say "onto other animals." Or did you just accidently disclose your real problem with EP?
Like you, I found EP accounts to be fascinating, but you've hit the nail on the head - evolutionary biology at its best can tell us what sort of traits -got selected-, without being able (at present even in principle), to tell us what traits -got selected for-.
I don't see where Matt said that at all. He said that your "just-so stories" assertion could be made about physical as well as psychological traits, and that while EP theories may be harder to test than theories regarding the evolution of physical traits, they are subject to the same kind of empirical and theoretical tests. Is the trait adaptive? Is the theory consistent with the results of observation and experiment? Is it consistent with existing established theory? That kind of thing.
I don't even really understand what your latest attempt to explain your supposedly substantive objection to EP is supposed to mean. If I understand your statement correctly, the objection is something like "EP can tell us what traits got selected, but not what they got selected for." Psychological traits are selected for the same purpose as physical ones: to enhance reproductive fitness. They're selected because they are adaptive. The psychological trait in males of a desire for many sexual partners was selected because males who possess that trait tend to leave more surviving offspring than males who lack it. I don't think this is exactly hard to understand.
Some of those basic premises are based on anthropological work on hunter-gatherer groups that have existed in recent history, and that work, while interesting, has a tendency towards sporadic radical revision (remember when it was thought that the !Kung were basically pacifists?) Furthermore, details matter - were the social groups of early humans quite egalitarian, as some such groups are, or did they have formal status hierarchies, or some mix of the two? What sorts of animals were the actual predators of early hominids? This matters for what sorts of predator-avoidance mechanisms you'd like to posit - if you are mostly afraid of snakes, it makes sense, like some squirrels, to be able to shunt lots of blood very quickly to your extremities, to mislead the snake as to where your center of mass is. If you are predated by raptors or cats, however, this will not have much impact on your reproductive fitness.
Some of thsoe basic premises are obviously true of the Way Things Used To Be; but the details end up mattering a great deal, and while I understand that you feel there is really a very strong consensus on said details, I think a quick look through the literature of the fields that most directly examine neural and cognitive processes will reveal that there is not a strong mapping between any putative set of these details and the concerns of those fields.
Hunting and foraging, therefore coincidence detectors for interaural time difference calculation at a threshold of 3 microseconds is not an inference I'm comfortable with.
Some of those basic premises are based on anthropological work on hunter-gatherer groups that have existed in recent history, and that work, while interesting, has a tendency towards sporadic radical revision (remember when it was thought that the !Kung were basically pacifists?) Furthermore, details matter - were the social groups of early humans quite egalitarian, as some such groups are, or did they have formal status hierarchies, or some mix of the two? What sorts of animals were the actual predators of early hominids? This matters for what sorts of predator-avoidance mechanisms you'd like to posit - if you are mostly afraid of snakes, it makes sense, like some squirrels, to be able to shunt lots of blood very quickly to your extremities, to mislead the snake as to where your center of mass is. If you are predated by raptors or cats, however, this will not have much impact on your reproductive fitness.
Some of those basic premises are obviously true of the Way Things Used To Be; but the details end up mattering a great deal, and while I understand that you feel there is really a very strong consensus on said details, I think a quick look through the literature of the fields that most directly examine neural and cognitive processes will reveal that there is not a strong mapping between any putative set of these details and the concerns of those fields.
Hunting and foraging, therefore coincidence detectors for interaural time difference calculation at a threshold of 3 microseconds is not an inference I'm comfortable with.
Why is a trait selected for?
Because it's adaptive.
How is it adaptive?
Because it enhances reproductive fitness.
How do we know it enhances reproductive fitness?
Because it was selected for.
If you don't see the problem in this sort of reasoning, Mixner, then I think this is my last contribution to this thread.
1 Why is a trait selected for?
2 Because it's adaptive.
3 How is it adaptive?
4 Because it enhances reproductive fitness.
5 How do we know it enhances reproductive fitness?
6 Because it was selected for.
You lost me at 5. I'm not an expert on EP,(my exposure is from second hand pop science sources like Ridley, Ridley, Diamond, Dawkins, and such) but isn't this a bit of a strawman?
JAR,
Some of those basic premises are based on anthropological work on hunter-gatherer groups that have existed in recent history,
Which ones? Your posts are full of these vague allusions to alleged problems that you fail to articulate in any clear way. None of the premises I listed depend on observations of hunter-gatherer groups in recent history. They are all amply supported by evidence from paleontology, paleoanthropology, genetics, and other fields. Evolutionary psychologists are well aware that, for a variety of reasons, modern hunter-gatherer cultures are most likely highly unrepresentative of ancestral hunter-gatherer cultures in many important respects.
Furthermore, details matter - were the social groups of early humans quite egalitarian, as some such groups are, or did they have formal status hierarchies, or some mix of the two? What sorts of animals were the actual predators of early hominids? This matters for what sorts of predator-avoidance mechanisms you'd like to posit
No, those details don't matter either to EP in general or to any of the particular EP theories that have been mentioned here (parental investment, reciprocal altruism, etc). Again, if you have a clear argument to make against a particular EP theory, or against EP in general, on the basis of what you claim to be our ignorance of a relevant aspect of our ancestral environment, then make it. Simply saying "We don't know what actual predators they faced" is not an argument.
If you don't see the problem in this sort of reasoning, ...
I do see a problem with it, but since I haven't invoked anything like "that sort of reasoning," I can only assume this is yet another entry in your apparently endless parade of irrelevancies and digressions. No one has said that we know male promiscuity enhances reproductive fitness "because it was selected for." It was selected for because it enhances fitness, and we know it enhances fitness from well-understood biological mechanisms having to do with the relationship between sex and pregnancy.
JAR,
I think you have a point there, but I also think there are a lot of cases where it's pretty easy to infer why or how a given trait enhances reproductive fitness even in cases where we can't directly observe it. The ability to digest milk would be a good example. We can't say for certain that it provides a reproductive advantage, but it's easy to understand why it would.
I think EP can still make some pretty strong cases in instances like those.
I also need to deal with this loose end:
JAR,
As a final note, I'm not sure that you really want to cite the winning of prizes as proof of the veracity or utility of a particular theory. Let us remember that the man who pioneered the frontal lobotomy won a Nobel Prize.
I consider the awarding of the Nobel Prize (and its equivalent, the Crafoord Prize) to be a very good indicator of the likely quality of scientific work. Trivers was awarded the Crafoord Prize specifically for his work in evolutionary psychology, which is a powerful testament to the quality of that work.
I don't know who you're referring to in the statement above (yet another one of your vague allusions), or if he was awarded his Nobel for "pioneering frontal lobotomy" rather than for some other work he did, or what the quality of the work for which he received the prize was (you seem to be expecting us to assume that "pioneering frontal lobotomy" could not involve scientific work worthy of a Nobel), but in any case, the mere fact that a Nobel Prize winner has been involved in other scientific work of dubious value does not at all detract from the quality of the work for which he was recognized. William Shockley was involved in some very dubious theories regarding race and intelligence, but his work on electronics and the development of the transistor, for which he was awarded the 1956 Nobel Prize in Physics, is generally regarded as stellar.
The animal kingdom is mostly insects and fish, who happily chow down on their brethren all the time.
True, many insects do that. Fish species usually don't, though (they do if you cram them into a fish tank together, but that's an extreme circumstance). But like you said, mammals avoid it, and we're mammals. It can't be social conditioning because non-social mammals don't do it either. If it isn't social it has to be hereditary, and that means that it is almost certainly the result of evolutionary pressures.
Well there are certain people who have indeed become rich, through free trade, at the expense of someone else. Of course, there are certain people how have become rich without the use of free trade at the expense of someone else.
That doesn't mean go protectionist tho...
And yes, there are people who have become not at the expense of someone else.
You lost me at 5. I'm not an expert on EP,(my exposure is from second hand pop science sources like Ridley, Ridley, Diamond, Dawkins, and such) but isn't this a bit of a strawman?
Why is it a strawman? In practice, a tautology is about as far as this kind of logic can go when pushed to the wall. That's why EvoPsy and certain strains of EvoBio are distrusted in some quarters: the explanations have neither a testable hypothesis nor a clear historical accounting to draw from, so the theorizings are unavoidably conjectural and circular, and might just as well have come from eight beers and an Ouija Board.
The person I was referring to is Antonio Egas Moniz. He even has his own Wikipedia article, if you care to read it.
That's why EvoPsy and certain strains of EvoBio are distrusted in some quarters: the explanations have neither a testable hypothesis nor a clear historical accounting to draw from
Evolutionary psychology theories are difficult, but not necessarily impossible, to test. Obviously we can't prove that trait X exists because of evolutionary factor Y, but that's true for every aspect of evolution.
There are a lot of aspects to human psychology that are definitely biological in origin. That means that we evolved those traits. Evolutionary psychology attempts to explain why, and how. The opposition comes mostly from "neck-down" evolutionary biologists (e.g. Gould) who disagree with the notion that there ARE inherent biological aspects to human psychology.
With regard to the specific claim that females are genetically predisposed to form pair-bonds with "reliable" males, but mate surreptitiously with "attractive" males, so that their offspring will be "attractive" and reproduce successfully:
How is this an advance on the more general assertion that a female with a choice would rather have sex with the more "attractive" of two potential partners? And how tautologous is that statement, given that the definition of "more attractive" is "preferred as a sexual partner"? (And how are females different from males in this regard?)
In theory, I guess one could test the validity of the thesis as applied to humans* as follows: Monitor a cohort of women with non-sexy husbands and sexy boyfriends, and find out whether they are less likely to use contraception with the boyfriends. But given that most such women want to keep the boyfriends a secret, how do you recruit an unbiased sample?
* I suspect that there would be much less interest in this topic if people weren't thinking about humans when they are discussing it. Not that many people are fascinated by the reproductive habits of reed warblers.
I can definitely understand why you're skeptical regarding explanations based on evolutionary psychology. Because this post and many of the comments display a dismayingly simplistic and inaccurate understanding of those explanations.*
For instance, the theory about male promiscuity and female reticence is based largely on the huge investments women must make in children (read: gene propogators) compared to men--starting with a very high risk of death in childbirth (resulting from large brains hence heads and small birth canals resulting from upright-posture hip architecture), and continuing through at least many months and probably many years of requisite caregiving. That's just for starters.
The "economics" of that situation are not ambiguous, and are completely different from those for dung flies. You know where God is...
You can't run clinical trials on this stuff, but you can base judgments on a comprehensive and comparative understanding of different species' biological and ecological situations.
Meanwhile, the Dutton piece that causes you to nod approvingly is well out there on the speculative fringe.
* Demonstrative of this: there's not a single mention of childbirth on this page.
The arguments above seem to lack an evolutionary focus. eg How did the noted behavior create more biologically related children over the long run. Long runs are the accepted time frame for evolution. Were all the really promiscuous women wiped out by jealousy? Died in childbirth because their sisters wouldn’t help them get the baby out?
It would be difficult to make a case that women have been historically promiscuous (at any kind of rate approximating male behavior).
Finn, there are ~ 1.05 male live births per female live birth. The average human female must therefore have had 1.05 times as many sexual partners as the average male.
Women may have been more interested in the quality of their partners than men, but they cannot on average have had any fewer.
It makes intuitive sense to me--this may be why (bad) arguments in favor of protectionism are an easier sell than (good) arguments in favor of free trade. But still, my doubt remains . . .
Why trust this story more than the ones you doubted? The arguments in favour of free trade require whole sentences and the attention of the listener. The argument for protection is that “we should protect our people at the expense of foreigners”.
To a voter who listens with half an ear to one sentence at the most, the simple argument wins.
Ad, I think you should reexamine your argument about what the 1.05 number implies.
As to the rest: behaviour is is a heritable. The same as any other heritable trait. So it follows that the same principles of random variation and selection for fitness apply, the same as for abilities to digest different types of plants or animal products, or the ability to see color.
Iow, bumblebees don't exhibit the behaviour of stalking and attacking grasshoppers for very good evolutionary reasons.
I deliberately chose an example from the class (or is it order) of insects, because this illustrates why behaviour as a heritable trait tends to differ from other, purely morphological traits: behaviour in the lower animals is very much determined by hard-wiring. Progessing in neurological complexity generally renders this assumption less and less tenable. For example, while stalking play is easily observed in kittens of all sizes, the actual business of stalking, attacking, and killing prey seems to be more of a learned behaviour in the big cats.
And in humans, of course, this assumption becomes extremely problematic, because there are effects of culture, i.e., non-genetically transmitted behaviours that one has to contend with and filter out.
The bottom line is that evolutionary psychology nee psychobiology is a valid field, albeit one more difficult to practice in.
And in humans, of course, this assumption becomes extremely problematic, because there are effects of culture, i.e., non-genetically transmitted behaviours that one has to contend with and filter out.
The effects of culture can be a confounding factor for some evolutionary psychological theories (and also some theories of physical evolution), but do not preclude robust conclusions about the role of adaptation and other evolutionary processes in determining human psychological traits. Psychological traits found in all recorded human cultures are very likely to be strongly determined by biology, even in cases where culture has acted to amplify or elaborate the trait (such as male dominance of politics and government). Similarly, psychological traits found in humans that are also found in other species that share relevant aspects of our biology (such as differences in the minimum investment each sex makes in reproduction) are also very likely to be strongly determined by biology. In some cases, culture acts against the trait, and its prevalence in the face of that influence testifies to the strength of the underlying biological drive. For example, adultery is common despite strong social disapproval and the cultural support for institutionalized monogamy in marriage. Parents are far more likely to abuse their stepchildren (in whom they have no genetic investment) than their biological children despite strong social and legal sanctions against all child abuse.
ScentOfViolets, I apologise:
"there are ~ 1.05 male live births per female live birth. The average human female must therefore have had 1.05 times as many opposite sex sexual partners as the average male."
there are ~ 1.05 male live births per female live birth. The average human female must therefore have had 1.05 times as many opposite sex sexual partners as the average male.
Really dumb argument. Males get themselves killed at a much higher rate than females, so the numbers even out in the end.
There is no logical relationship between the ratio of births by sex and the average number of (opposite sex) sexual partners by sex. In any case, average number of sexual partners is not a very relevant statistic. Men tend to seek or desire more sexual partners than women, whether they are able to actually acquire them or not. Women who seek very large numbers of sexual partners usually do so for money rather than sexual gratification. That is, they are usually prostitutes. Male prostitution, in contrast, is much rarer, and most customers of male prostititutes are gay men, not women.
The weakness of Evolutionary Psychology as a science is precisely the same weakness as Economics as a science. Which is why I'm always surprised when economists complain about evolutionary psychologists.
The controlled experimentation required to really nail down hypotheses runs into some hefty ethical considerations when we try to apply them to humans. We can't breed humans like we do with fruit flies, for instance. So instead we are stuck with making models and hoping that they bear some semblance to reality.
In some cases, culture acts against the trait, and its prevalence in the face of that influence testifies to the strength of the underlying biological drive. For example, adultery is common despite strong social disapproval and the cultural support for institutionalized monogamy in marriage.
I think this is exactly backwards. It is the institution of marriage, as traditionally constituted in many societies including ours, that argues rather strongly for evolutionary biology. All that effort by men to maintain exclusive sexual access to their wives = genetic imperative to make sure your children really do have your genes.
Oh and while we're on the subject of male promiscuity/female chastity: the average (mean) number of sexual partners has to be equal for men and women. (Assuming a closed group of heterosexuals.) But:
1. The distribution can be wildly different. i.e. big bulge at the high end of # of sexual partners for women--read: prostitutes. (Where money and birth control trump evolutionary drives.) Flatter distribution for men, resulting in higher numbers in the center. So the *typical* (median) man has more sexual partners than the typical woman.
2. Homosexuality skews the numbers in various ways.
3. Probably a small effect, but it's not a closed system--there's outsourcing to and immigration from foreign countries.
4. In surveys, because of cultural expectations, men probably lie upwards, and women probably lie downwards. So to speak.
The controlled experimentation required to really nail down hypotheses runs into some hefty ethical considerations when we try to apply them to humans. We can't breed humans like we do with fruit flies, for instance. So instead we are stuck with making models and hoping that they bear some semblance to reality.
Another silly comment. We don't need to breed humans like fruit flies, or take similarly draconian measures, to "really nail down" hypotheses about human nature, either in EP or any of the other social sciences. It's as silly as claiming that we would need to travel back in time and observe physical changes as they were happening in our ancestors in order to "really nail down" hypotheses about the evolution of physical human traits. The fact that ethics or physics or other constraints prevent us from conducting certain types of experiment or observation that might be useful if they were available to us does not preclude us from amassing compelling evidence for a hypothesis through other types of experiment or observation that are available to us.
I think this is exactly backwards. It is the institution of marriage, as traditionally constituted in many societies including ours, that argues rather strongly for evolutionary biology. All that effort by men to maintain exclusive sexual access to their wives = genetic imperative to make sure your children really do have your genes.
I'm not sure why you think that is "backwards" to what I wrote. The genetic imperative you describe would create an urge for exclusive access, but not for monogamy. I think the prevailing view among cultural anthropologists is that monogamous marriage is a relatively recent invention in human culture and arose primarily as a means of reducing conflict between men for sexual access to women. If each man has only one (exclusive) wife, then every man can have one. If some men have more than one wife (polygamous marriage), then others must go without, which creates conflict.
How is this an advance on the more general assertion that a female with a choice would rather have sex with the more "attractive" of two potential partners? And how tautologous is that statement, given that the definition of "more attractive" is "preferred as a sexual partner"? (And how are females different from males in this regard?)
I don't know what you mean by "how is this an advance." In their choice of sexual partners, women tend to emphasize wealth, social status and maturity, since men with those qualities are more likely to stick with her and help raise and provide for her offspring. Men, in contrast, tend to emphasize youth and other physical characteristics correlated with biological fertility. Female fertility declines with age much more quickly than does male fertility, which is why men tend to value youth in their sexual partners much more highly than women do. Again, there are various caveats and qualifications to this, but that's the basic pattern of difference in male and female sexual preferences, and it has been confirmed through studies of thousands of modern and historical cultures.
Mixner, that's not my understanding of the prevailing wisdom. Actually smacks of group-selection theorizing, which is quite (though not completely) out of favor these days.
Males with multiple wives has been the norm in the bulk of societies, I'm pretty sure. And yes, as a result, some males do without. Alternatively, monogamy with mistresses. Strict monogamy is something that's arisen increasingly with modern culture, but as our gubernatorial instigator reminds us, culture is hard-pressed to enforce it...
Males with multiple wives has been the norm in the bulk of societies, I'm pretty sure.
Right. That's why I said, "I think the prevailing view among cultural anthropologists is that monogamous marriage is a relatively recent invention in human culture." Most historical human cultures have been polygamous. Pinker puts the figure above 80%.
Roac,
This brings up an interesting point. There is such a thing in evolution as a "feedback loop", escpecially in regards to sexual selection, as opposed to pure "natural selection". The power to select sexual partners can in fact create odd situations which actually go against the grain of personal survival. One of the most frequently cited examples is in peacocks. Male peacocks have huge and beautiful tail feathers because female peacocks are attracted to them. Because female peacocks are attracted to males with big, beautiful tail feathers, their male offspring are more likely to have big, beautiful tail feathers. Ad infinitum. What you end up with is a whole class of males whose tail feathers are so big and cumbersome that it actually reduces their ability to hunt, evade prey, etc. And yet, because females continue to choose males with these big tails, the trait not only persists, but intensifies.
THere's many examples like this in the animal kingdom, but the most relevant one may be human intelligence itself. Evolution has a hard time explaining human intelligence by conventional survival and adaptation advantages. To be blunt, humans are way smarter than they need to be to hunt, gather food, protect themselves from predators, etc. Likewise, having big brains is very costly in terms of high-quality meats and other foods, and what it takes to acquire these, and maintain them. It's been calculated that there's no survival need for human beings to be much more intelligent than wolves, say. So why are we so smart. EP theory suggest one explanation: that sexual selection, primarily on the part of females, has driven the evolution of intelligence. That human females, like pean hens, have chosen males who are more intelligent, creative, artistic, and just plain "entertaining", simply because they like those traits. One can certainly imagine how females might choose to mate with the guys who were smart and creative enough to keep them entertained through those long, million-year nights around the campfire. It would also explain why women are always suckers for rock stars, actors, poets, artists, musicians, etc. So the EP theory of sexual selection for intelligence is that this became a kind of runaway train, not driven by actual survival benefits, but by sexual preference. Until, of course, at a certain point intelligence itself began to show real survival advantages in the cultural sense. Smarter men could outcompete stupider men in many important respects. But such competition itself really breaks down to sexual selection in the end, in that being able to outcompete other men ensures more sexual partners, and the survivability of human children into adulthood, past the time of their dependency.
One other general thing to mention about EP is that it doesn't suggest there is only one, single optimal reproductive strategy, but quite the opposite: that oftentimes the optimum reproductive strategy is to go against the norm, to choose counter-strategies that find holes in the dominant strategy, and even to develop counter-coutner strategies. Thus, some women fall into the pattern of loyal, monogamous wives, and some men fall into the pattern of loyal, monogamous husbands. But there are advantages to going against this grain, by being promiscuous, especially if no one else is. The more popular promiscuity is, however, the less of an advantage it becomes. So there is a constant shifting of strategies. Megan should understand this in terms of economic theory, which rewards scarcity and innovation. EP is not really any different in the basics, and I think she would appreciate it better if she actually understood the theory better.
Re: Demonstrative of this: there's not a single mention of childbirth on this page.
When we are talking about humankinds' physical evolution childbirth is a very important matter for the reasons you cite. However it's less clear that it plays a major role in the evolution of the relations between the sexes. What a woman giving birth needs in a primitive society is not a male (who probably knows little or nothing about the process) but rather one or more experienced and older females to assist her. One could derive from that a hypothesis that this limits female prosmicuity so the birthing woman will not have created too much antagonism towards her from her sisters, but that's about as far as I can see taking that.
Re: Males get themselves killed at a much higher rate than females, so the numbers even out in the end.
Not even sure that that's the reason. I've seen studies suggesting that males on the average have slightly weaker immune systems than females, and as such will be more likely to die in childhood.
Re: Males with multiple wives has been the norm in the bulk of societies, I'm pretty sure.
Even in societies which allow it, polygamy is the exception not the norm, limited to high-status males who can afford multiple wives and the large number of children it can produce. Most of humankind is monogamous (officially at least), unless you regard serial monogamy produced by remarriage after divorce and widowhood as a form of polygamy. Also, too much polygamy will create an unstable society due to a large numbers of sexually frustrated young men without mating prospects. No society can survive with too many violent and alienated men in it. The Middle East's troubles are a case in point.