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Tongue-in-cheek relationship advice from evolutionary psychology (via Mindhacks.)
Some Darwinists might say your optimal strategy would be to pair-bond with the older male but surreptitiously allow the younger, sexy male to fertilise you. But be careful, most men consider being cuckolded the greatest of betrayals.
And how about this?
You should have your husband medically assessed. It may be that some form of genetic disorder underlies his erratic behaviour, in which case he will need counselling and support. But you will also need to inform your daughters so that, if they are carriers, they do not themselves mate with men suffering from the same condition.
A simple implication of sexual selection is that there should be a correlation between features that attract us sexually and characteristics that make our offspring more fit. Here is an article that studies the link between physical attraction and success in sport.
The better an American football player, the more attractive he is, concludes a team led by Justin Park at the University of Bristol, UK. Park’s team had women rate the attractiveness of National Football League (NFL) quarterbacks: all were elite players, but the best were rated as more desirable.
Meanwhile, a survey of more than a thousand New Scientist Twitter followers reveals a similar trend for professional men’s tennis players.
Neither Park nor New Scientist argue that good looks promote good play. Rather, the same genetic variations could influence both traits.
“Athletic prowess may be a sexually selected trait that signals genetic quality,” Park says. So the same genetic factors that contribute to a handsome mug may also offer a slight competitive advantage to professional athletes.
Studies like this are prone to endogeneity problems because success also feeds back on physical attraction. At the extreme, we know who Roger Federer is and that gets in the way of judging his attractiveness directly. More subtly, if you show me pictures of two anonymous athletes, the one who is more successful has probably also trained better, eaten better, been raised differently and these are all endogenous characteristics that affect attractiveness directly. Knowing that they correlate with success doesn’t tell us whether “success genes” have physically attractive manifestations.
One way to improve the study would be to look at adopted children. Show subjects pictures of the athletes’ biological parents and ask the subjects to rate the attractiveness of the parents. Then correlate the responses with the performance of the children. If these children were raised by randomly selected parents (obviously that is not exactly the case) then we would be picking up the effect of exogenous sources of physical attractiveness passed on only through the genes of the parents.
And why stop with success in sport. Physical attractiveness should be correlated with intelligence, social mobility, etc.
From an entertaining article in the Financial Times that develops the analogy between the interconnectedness of financial instruments and biological ecosystems.
“From an individual firm’s perspective, these strategies looked like sensible attempts to purge risk through diversification: more eggs are being placed in the basket,” says Mr Haldane. “Viewed across the system as a whole, however, it is clear now that these strategies generated the opposite result: the greater the number of eggs, the greater the fragility of the basket – and the greater the probability of bad eggs.”
That is what a mathematical ecologist would have predicted if he or she had known what was going on in the world of finance. The tropical rainforest, for example, has so many interdependent species that it is more vulnerable to an external shock than the simpler ecological diversity of savannahs and grasslands.
I wonder what prescription naturally arises from this perspective? Total laissez-faire so that the financial system can suffer enough crashes, extinctions, and re-organizations to find a configuration that is stable for the long run? Would we someday see Business schools sending missions out to shuttering financial institutions clamoring for intervention in the name of preserving derivative-diversity. What is the analog of sexual reproduction and random genetic mixing?
Sex is a puzzle for evolutionary biologists. It seems to be a waste of reproductive output. A population of a fixed size which requires two members to produce offspring reproduces, and therefore grows, at half the rate of the same sized asexsual population (which requires only one member to produce one offspring.)
So to explain the prevalence of sexual reproduction in nature we need to find some advantage to offset this so-called two-fold cost of sex. There are two prominent theories. The first is that sexual reproduction allows a species to shed disadvantageous mutations. Sexual reproduction thus ensures that offspring loses any harmful mutation with probability 1/2 (we are assuming that the parents do not have mutations of the same gene, a good approximation when there are many genes.) But with asexual reproduction, these mutations just accumulate.
Another theory is that sexual reproduction, by mixing around genes, ensures genetic diversity which enables a species to survive changes in the environment.
Not Exactly Rocket Science reports on an experiment designed to test these theories.
Like humans, C.elegans has two sexes but unlike us, they are males and hermaphrodites (with males making up just one in every two thousand individuals). Equipped with both sets of genitals, hermaphrodites worms can fertilise themselves without male help – far from being rude, telling C.elegans to go &$&! itself is a feasible lifestyle suggestion. Hermaphrodites could also mate with males, but they do that on less than one in 20 occasions.
The biologists manipulated the genetics of a population of these worms so that half would always mate with themselves and the others would always mate sexually. Next, they exposed the worms to a chemical that raised their rate of mutations. As the theory predicts, the sexually reproducing worms were more successful.
Next, they exposed the worms to a deadly bacterium. Consistent with the second theory, the sexually reproducing worms also fared better in this experiment.
Now the big puzzle. If sexual reproduction is beneficial, why do all sexually reproducing species in nature do it in pairs? This paper by economists Motty Perry, Phil Reny, and Arthur Robson proves that, at least with respect to the harmful mutation theory, a particular form of tri-parental sex dominates bi-parental sex. In the Perry-Reny-Robson world, reproduction requires two males and one female. The offspring receives genes with half-probability from the mother and 1/4-probability from each of the fathers.
(With this particular menagerie, in every reproductive cycle each female gets two partners per encounter but each male gets two encounters. Not only does this ensure that the “cost of sex” is again two-fold and not three-fold, but it also maintains equity in the gettin’ busy department. Only fair.)
The Boston Globe has an interesting article about the unique playout of the creationist/Darwinist debate in the Islamic world.
Unlike in the West, creationist beliefs are not associated in the Muslim world with religious fundamentalism, but instead are often espoused by members of the mainstream intellectual elite – liberals, by their own lights, who see the expansive, scientific-sounding claims of creationism as tracing a middle way between the guidance of religion and the promise of modern science. Critics of the movement fear that this makes it more likely that creationism will find its way into policies there, especially when the theory of evolution is portrayed among Muslim thinkers, as it often is, as an instrument of Western intellectual hegemony.
That seems to be the thesis of this paper by neurobiologist Jerome Siegel:
Sleep can be seen as an adaptive state that benefits animals by increasing the efficiency of their activity. It does this by suppressing activity at times that have maximal predator risk and minimal opportunity for efficiently meeting vital needs, and by permitting activity at times of maximal food and prey availability and minimal predator risk.
I read this as arguing that if an animal is not sleeping it will do things that are not in its interest. So sleep stops it from doing those things. Of course natural selection could instead have simply taught the animal not to do what’s against its self interest but instead, under this theory, sleep acts like a commitment device to blunt a self-control problem.
Via neuroskeptic.
Let’s say you read a big book about recycling because you want to make an informed decision about whether it really makes sense to recycle. The book is loaded with facts: some pro, some con. You read it all, weigh the pluses and minuses and come away strongly convinced that recycling is a good thing.
But you are human and you can only remember so many facts. You are also a good manager so you optimally allow yourself to forget all of the facts and just remember the bottom line that you were quite convinced that you should recycle.
This is a stylized version of how we set personal policies. We have experiences, collect data, engage in debate and then come to conclusions. We remember the conclusions but not always the reasons. In most cases this is perfectly rational. The details matter only insofar as they lead us to the conclusions so as long as we remember the conclusions, we can forget about the reasons.
It has consequences however. How do you incorporate new arguments? When your spouse presents arguments against recycling, the only response you have available is “yes, that’s true but still I know recycling is the right thing to do.” And you are not just being stubborn. You are optimally responding to your limited memory of the reasons you considered carefully in the past.
In fact, we are probably built with a heuristic that hard-wires this optimal memory management. Call it cognitive-dissonance, confirmatory-bias, whatever. It is an optimal response to memory constraints to set policies and then stubbornly stick to them.
Its easy to make up just-so stories to explain differences across siblings as being caused by birth-order. This article casts doubt on the significance of birth order.
But we can ask the question of whether birth order should matter and in what ways. Should natural selection imply systematic differences between older and younger siblings? Here is one argument that it should. Siblings “share genes” and as a consequence siblings have an evolutionary incentive to help each other. Birth order creates an asymmetry in the ways that different siblings can help each other. In particular, oldest siblings learn things first. They are the first to experiment with different survival strategies. The results of these experiments benefit all of the younger siblings. (Am I a good hunter? If so, my siblings are likely to be good hunters too.) Younger siblings have less to offer their older siblings on this dimension.
As a result we should expect older siblings to be more experimental than their younger siblings and more experimental than only children.
Here is evidence that older siblings have more years of education than younger siblings and more years of education than only children.
When animals move, forage or generally go about their lives, they provide inadvertent cues that can signal information to other individuals. If that creates a conflict of interest, natural selection will favour individuals that can suppress or tweak that information, be it through stealth, camouflage, jamming or flat-out lies. As in the robot experiment, these processes could help to explain the huge variety of deceptive strategies in the natural world.
The article at Not Exactly Rocket Science, describes an experiment in which robots competed for food at a hidden location and controlled a visible signal that could be used to reveal their location. The robots adapted their signaling strategy by a process that simulates natural selection. Eventually, the robots learned not to pay attention to others’ signals and the signals become essentially uninformative.
The financial markets are deregulated, banks are “too big to fail”, interest rates were kept low by Alan Greenspan etc…are these the only issues that caused the financial crisis?
Malcolm Gladwell has a very interesting article suggesting overconfidence played a role in causing the bubble that eventually burst. The main protagonist in the story is Jimmy Cayne, former C.E.O. of Bear Stearns. The man was sometimes confident and perhaps over confident:
The high-water mark for Bear Stearns was 2003. The dollar was falling. A wave of scandals had just swept through the financial industry. The stock market was in a swoon. But Bear Stearns was an exception. In the first quarter of that year, its earnings jumped fifty-five per cent. Its return on equity was the highest on Wall Street. The firm’s mortgage business was booming. Since Bear Stearns’s founding, in 1923, it had always been a kind of also-ran to its more blue-chip counterparts, like Goldman Sachs and Morgan Stanley. But that year Fortune named it the best financial company to work for. “We are hitting on all 99 cylinders,’’ Jimmy Cayne told a reporter for the Times, in the spring of that year, “so you have to ask yourself, What can we do better? And I just can’t decide what that might be.’’ He went on, “Everyone says that when the markets turn around, we will suffer. But let me tell you, we are going to surprise some people this time around. Bear Stearns is a great place to be.’’
Gladwell connects overconfidence to success at some games people play in nature and refers to work by biological anthropologists. This all seems quite interesting and I can see chasing it up for fun. But he then goes on to try to connect Cayne’s overconfidence to his success at bridge – appreantly he is an excellent player and it helped him get his job at Bear Stearns. This is a disconnect. Bridge is a zero-sum game. Behavioral biases such as overconfidence lead people to make mistakes and hence lose out more than people who judge hands correctly. If Cayne is good at bridge, he must judge probabilities accurately rather than exaggerating his odds of success. This then implies that he is less likely to be overconfident than others working in finance who are perhaps bad at bridge and poker as they are overaggressive.
So, while Gladwell may have a point to make, he does not do it convincingly as his main example concerns a protagonist who is less likely to be overconfident as he is good at zero-sum games.
Evolutionary Psychology and, increasingly, behavioral economics spin a lot of intriguing stories explaining foibles and otherwise mysterious behaviors as the byproduct of various tricks nature utilizes to get us to do her bidding. I am on record in this blog as being a fan of this methodology. But I also maintain a healthy skepticism and not just at the tendency to concoct “just-so” stories that often ask us to reformulate our theories of huge chunks of evolutionary history just to explain some nano-economic peculiarity.
Instead, when evaluating some theory of how emotions have evolved to induce us to behave in certain ways, skepticism should be aimed squarely at the basic premise. The theory must come with a convincing explanation why nature would rely on a blunt instrument like emotions as opposed to all of the other tools at her disposal. These questions seemed especially pressing when I read the following article about depression as a tool to blunt ambitions:
Dr Nesse’s hypothesis is that, as pain stops you doing damaging physical things, so low mood stops you doing damaging mental ones—in particular, pursuing unreachable goals. Pursuing such goals is a waste of energy and resources. Therefore, he argues, there is likely to be an evolved mechanism that identifies certain goals as unattainable and inhibits their pursuit—and he believes that low mood is at least part of that mechanism.
Why not a simpler mechanism: just have us figure out that the goal is unattainable and (happily) go do something else? Don’t answer by saying that this emotional incentive mechanism evolved before our brains were advanced enough to do the calculation because the existence of an emotional response indicating the right course of action presupposes that this calculation is being made somewhere in the system.
Even granting that nature finds it convenient to do the calculation sub-(or un-)consciously and then communicate only the results to us, why using emotions? Plants respond to incentives in the environment and they don’t need emotions to do it, presumably they are just programmed to change their “behavior” when conditions dictate. Why would nature bother with such a messy, noisy, and indirect system of incentives rather than just give us neutral impulses?
Finally, you could try answering with the argument that evolution does not find optimal solutions, just solutions that work. But that argument by itself can be made into a defense of everything and we are back to just-so stories.
De Waal’s own experiments suggest that capuchin monkeys are sensitive to fairness. If another monkey gets a tasty grape, they will not cooperate with an experimenter who offers a piece of cucumber (Nature, vol 425, p 297). A similar aversion has been spotted in dogs (New Scientist, 13 December 2008, p 12), and even rabbits seem affected by inequality, leading de Waal to believe that an ability to detect and react to injustice is common to all social animals. “Getting taken advantage of by others is a major concern in any cooperative system,” he says.
This article mostly just regurtitates some tired and fragile “evolutionary” explanations for fairness and revenge, but there are a few interesting tidbits, like some experiments with monkeys and this joke:
A genie appears to a man and says: “You can have anything you want. The only catch is that I’ll give your neighbour double.” The man says: “Take out one of my eyes.”
- The music of H1N1
- Justice Souter retiring?
- Hobbits.
- DOJ investigating Google Books settlement.
Female orgasm eludes evolutionary explanation. Most candidate explanations have a hard time reconciling the observation that a large fraction of women do not have orgasm during intercourse and among those that do it is not a consistent occurrence. Here is a fun paper surveying a variety of just-so stories that “explain” female orgasm. The authors dispense with
- Its a non-adaptive vestige of male orgasm.
- It encourages females to have more sex. (then why not always?)
- It encourages females to have sex with multiple partners (thus the asymmetry in “arrival times” between males and females.)
- It improves chances of fertilization. (empirically false)
and they leave us with an intriguing, relatively new one, the Evaluation Hypothesis.
When Barash was a graduate student more than ten years earlier, he observed that when subordinate male grizzly bears copulate, their heads are constantly swiveling about on the lookout for a dominant male, who, should he encounter a couple in flagrante, will likely dislodge his lesser rival and take its place. Not surprisingly, subordinate males ejaculate very quickly, whereas dominants take their time. If female grizzly bears were to experience orgasm, with which partner would you expect it to be more likely? And is it surprising that premature ejaculation is a common problem of young, inexperienced men lacking in status and self-confidence? Moreover, is it surprising that women paired with such men are unlikely to be orgasmic?
So it doesn’t encourage more sex uniformly, it encourages more sex with the right mate. And it is inconsistent and slow to arrive, not by accident, as in the vestigal hypothesis, but by design. And the sorting of men according to, let’s call it patience, seems to be a stable equilibrium as it requires either an exogenous characteristic correlated with “good genes” as in the case of dominant grizzlies, or perhaps in its social incarnation where it requires
sufficient access to resources to orchestrate interactions that are private, safe, and gratifying—in a word, romantic—and thus appealing to women’s evolved evaluation mechanisms.
From the book How Women Got Their Curves and Other Just-So Stories: Evolutionary Enigmas by David Barash and Judith Lipton. (Cloche Click: Bookslut.)
I collect examples of Kludges. Luis Rayo has sent me a very nice one.
In mammals, for instance, the recurrent laryngeal nerve does not go directly from the cranium to the larynx, the way any competent engineer would have arranged it. Instead, it extends down the neck to the chest, loops around a lung ligament and then runs back up the neck to the larynx. In a giraffe, that means a 20-foot length of nerve where 1 foot would have done. If this is evidence of design, it would seem to be of the unintelligent variety.
Apparently, some evolutionary biologists take this to be evidence of our fish ancestry.
“The circuitous path of the left recurrent laryngeal nerve in humans is evidence for their evolution from a fishlike ancestor… because the nerve remained behind this arch but still connected to a structure on the neck, it was forced to evolve a pathway that travels down to the chest, loops around the aorta and the remnants of the sixth aortic arch, and then travels back up to the larynx. The indirect path does not reflect intelligent design but can be understood only as the product of our evolution from ancestors having very different bodies.”
The latter quote is from “Why Evolution is True” by Jerry A. Coyne.
For the game theorists in the room, the difference must boil down to whether we have random matching across populations (case 1) or within a single population (case 2.)
Genetic evolution is a clumsy way to adapt to a changing environment. Our genes were presumably shaped by very different conditions than we face now. Why wouldn’t natural selection favor organisms who can adapt to current conditions and pass on these adaptations to their children? Wouldn’t we be more fit if Lamarck was right and if so, why was he so wrong?
Turns out he wasn’t so wrong after all.
This was the first evidence, now confirmed multiple times, that an experience of the mother (what she eats) can reach into the DNA in her eggs and alter the genes her pups inherit. “There can be a molecular memory of the parent’s experience, in this case diet,” says Emma Whitelaw of Queensland Institute of Medical Research, who did the first of these mouse studies. “It fits with Lamarck because it’s the inheritance of a trait the parent acquired. There is even some evidence that the diet of a pregnant mouse can affect not only her offspring’s coat color, but that of later generations.”
That is from an article in Newsweek on epigenetics. Here is more. And here is a blog about epigenetics.
This raises the theoretical question: if you were to design the system of inheritance, where would it be optimal to draw the line between those characteristics that should be hard-wired in genes and those that can adapt at higher frequencies? And wouldn’t that depend on the environment? So would the line be hard-wired or epigenetic? And which side of the line is that trait on?
And the same for food critics/wine tasters. Also, wine tasters generally drink in moderation whereas chefs and food critics have been known to carry a little extra weight.
In both cases, the choice of profession has revealed a taste for the respective delicacy. Winemakers love the taste of wine, chefs love the taste of food. And, as demonstrated by wine tasters, you can taste without consuming, and you can partake without consuming to excess. The wine tasters manage to achieve this but the chefs do not.
Evolution has given us taste as an incentive to acquire necessary nutrients. Pleasant taste is our reward for consuming. Presumably, sometimes we might prefer to consume less (maybe more) than what Mother Nature would prefer, so she gives us the sense of taste so that we internalize her preference. But we try to find ways to manipulate her incentive scheme and get this taste without consuming a lot, or even at all, viz. the wine taster.
Mother Nature is perfectly content to allow us to taste but not consume wine if we see fit. But when it comes to food, she insists that she knows better than us and she will not let us get away with just a nibble. As with the taste of wine, the taste of food draws us in, and we expect to have just a taste. But once the food is in front of us, the trap is set and she deploys her most powerful weapon: temptation that cannot be overcome.
An evolutionary explanation of time-inconsistency and a preference for commitment, a’la Samuelson and Swinkels.
I remember once thinking what an amazing stroke of luck it was that on the Earth there happen to be so many wonderful gifts for people to enjoy. For example, it seemed close to definitive proof of a benevolent God that tangerines were just hanging there from trees for us to pick and eat. Somebody had to understand us very well and care about us a lot to give us this delicacy for free.
Of course this is a fallacy. It was not the fruit that was designed for our taste buds but the other way around.
We need to be incentivized to consume whatever we need to survive. And there is no need to bring any Designer into the story because this can be taken care of by natural selection.
These points are nicely recounted in this TED lecture by Dan Dennett. However, he stops short of considering the plot twist in which we develop conscious thought and learn how to manipulate nature’s incentive scheme. It starts with nutra-sweet, vasectomies and pornography. That’s when the real game begins.
Most of us are “irrationally” afraid of snakes…but few of us are afraid of mushrooms. Since both can be potentially fatal and both can be good eating, this is puzzling.
Most of us are “irrationally” afraid of snakes…but few of us are afraid of mushrooms. Since both can be potentially fatal and both can be good eating, this is puzzling.That’s from “Information, Evolution and Utility,” a paper by Jeroen Swinkels and Larry Samuelson about why natural selection shaped our preferences the way it did. In their story, Nature accepts that there are things that we can learn that she hasn’t had time to program into us (like which mushrooms are safe to eat.) So instead of giving us a complete set of instructions for how to behave in every situation, she gave us beliefs and the instinct to experiment and learn. Then she lets us choose.
But there are somethings she knows better than us . For example that snakes will likely kill us. So, forseeing that these beliefs she has given us can, and often do, go astray, she builds in backup measures to stop us from acting on them in contexts where she is confident that she knows best. Hence irrational fears.
I think there is wide open arbitrage opportunity in behavioral economics to import ideas from principal-agent theory to explain why Nature (the principal) has given us (the agent) certain preferences (incentives.)
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