Apparently it has been an assumption for a long time in some circles that early sex by teenagers results in their later delinquency. Two recent papers demonstrate just how muddled this theory is (along with most theories generalizing about human behavior), because they differ in their conclusions based on how the data were analyzed. The first paper's ( Armour, S. and D.L. Haynie, 2007. Adolescent sexual debut and later delinquency. Journal of Youth Adolescence 36:141-152) purpose was to use data to support the theory, which it does. The second paper (Harden, K.P., J. Mendle, J. E. Hill, E. Turkheimer and R.E. Emery, 2008. Rethinking timing of first sex and delinquency. Journal of Youth Adolescence, in press) uses the same dataset to reach the opposite conclusion, that earlier sex reduces future delinquency.

The second group of authors of course claim that their analysis is the better one, and in this case it is true. These papers, in fact, are a good demonstration of one of the major problems of large-dataset human studies, which is that they only control for factors (in this case, survey responses about race, income, parent's education, GPA, drug use, etc.) that the researchers imagine could affect the data, and not all the other hundreds of factors that also could but are ignored out of practicality or researcher bias. The authors' hope is that their use of a giant dataset will obscure the fact that important information is lacking.

(Once again, we will put aside the first major problem of such studies, the use of self-reporting data. Of course since both groups of authors rely on them, neither mentions how unreliable they are, especially, one might assume, with regard to sexual experience. And one might also imagine that the group of people who are most likely to lie about sexual experience is teenagers.)

The reason the second study is the better analysis is because the authors recognize that pooling all the data loses important information. Meaningless averages are calculated by pooling teenagers from all cultures and walks of life. To a repeat a very nice analogy used by the authors of the second paper: if you wish to correlate meat consumption with life expectancy, and you compare two countries, one primarily meat-eating and another not, you find a positive relationship - higher meat-eating correlates with higher life expectancy. But a third ignored variable also correlates positively with meat-eating, and that is level of industrialization. So to truly understand the relationship between meat-eating and life expectancy, you must control for industrialization. When the analysis is rerun within one country, the correlation between meat-eating and life expectancy is negative.

In addition, what is found in both papers is simply correlation, not causation (a trap that first-year undergraduates are taught to avoid, and yet catches so many human-behavior researchers). That is, the only information one has after the meat study is that meat-eating is associated with lower life expectancy. The study has not shown that meat-eating causes lower life-expectancy.

These were the two main problems with the first paper. The authors pool individuals across a wide range of cultural norms, which gives them a spurious result, and then conclude that early teen sex causes delinquency when the two are only correlated. Even though they use a crude control for cultural influence (average reported age of first sex for a given teenager's high school) they ignore any potential unstudied factor that could cause both (just as industrialization causes both higher life expectancy, and more meat-eating), obscuring the results for individuals.

The second paper solves that problem by analyzing only the identical twins in the dataset (which was large enough for them to have data for 289 twin pairs), and therefore controlling for both genetics (which the twins share exactly) and environment (which twins living in the same household largely share). This is an appropriate twin analysis because (for this main point at least) the authors don't care about trying to separate genetics and environment to answer their question. (Twin studies that do confound objective data with subjective assumptions.)

On top of all this, though, is another major flaw in the dataset, which the second group of authors strangely acknowledge despite their analysis. The supposedly "independent" (time of first sex) and "dependent" (delinquency) variables are by definition related from the start, because in much of American society, teen sex itself is considered delinquent behavior. What they are doing is a bit like asking whether or not shoplifting is correlated with delinquency. This certainly confounds the first study.

What does it mean that the second study found that identical twins who have their first sexual experience earlier than their siblings are less likely to engage in delinquent behavior? The authors seem to feel they have no choice but to conclude that there is probably no relationship between these factors at all. Perhaps that is exactly what they would have found statistically if they had used a Bonferroni correction for their dozen or so analyses. Either that, or delinquency is caused by sexual frustration, and the problem of misbehaving teens is now solved.

Labels: behavior, environment, humans, morality, statistics

The coqui frog Eleutherdactylus coqui, a native of Puerto Rico, gets its species name from the shrill call produced by males seeking mates, which is surprisingly loud for a beast the size of a quarter. Anyone from a part of the world with native tree frogs generally appreciates the lovely sound of calling peepers in the spring. Unfortunately, when the coqui was introduced to lands without its native predators to keep its populations in check, the lovely peeping sound in the distance was transformed into an overwhelming, piercing cacophony, which can be heard here at the site for Hawaiian Ecosystems at Risk (HEAR), where there is bountiful information on the hundreds of alien invasive species devastating Hawai`i's ecosystems. Listen to the recording. Then imagine playing it through your surround sound system at full wattage, and you will begin to get the idea of one of the problems caused by this species. After dusk, one literally has to yell to carry on a conversation at one house I have visited in Kurtistown (which lies between Hilo and Volcano on the Big Island).

Here is a youtube video of a single calling male. Well, puppies are cute too, but no one wants to live next to a kennel, do they? Even from a purely anthropocentric perspective, this invasive has much more direct effects on property values than any other. Control efforts are detailed at the University of Hawai`i College of Tropical Agriculture site.

While the attempted control of a tiny frog meets with far less opposition than previous plans to kill destructive feral cats in Volcanoes National Park, some PETA-types of course object. But even if you can tolerate the highly unnatural, deafening noise, anyone who cares about the ecological integrity of the Hawaiian Islands understands that coquis are a destructive pest that is incompatible with efforts to conserve endemic Hawaiian species (many of which are of course are living animals also).

Although predators in its native land clearly make an impact on coqui populations, it is remarkable how difficult it is, for humans at least, to localize a single calling frog. Apparently this is what the recent producers of smoke alarms were trying to emulate when they designed the system in which a dying battery causes the alarm to beep at long intervals. If your spouse, like mine, believes him- or herself to be the household's safety police, then you have about a dozen of these things littering your home, in every room. So, being able to find the one whose battery is dying is no trivial task. These contraptions strive to imitate the behavior of chirping frogs: as one attempts to hone in on the sound, they fall silent, in order to confuse and frustrate you, their predator.

As I have stalked around the second floor of the house, frozen for 30 seconds or more at a time, waiting for the next beep, my sympathies fall more into line with my father, who was decidedly not the Safety Monitor of our family. When smoke alarms first became available, my mother, whose very natural fear of house fires was grounded in personal experience, installed a single one in our split-level house. The first time it went off (the usual false alarm, of course, caused by kitchen smoke or whatnot) my father brandished a hatchet at the alarm, threatening over the excruciating whine to chop it to bits. Somehow my mother got the alarm away from him and turned off before he was able to make good.

My patience with the smoke alarms has run thin as well, every time I have to hurl one out the back door because my spouse insists on placing it in the kitchen, in defiance the manufacturer's instructions. "Ever heard of the smoke alarm that cried wolf?!!" I bellow.

But the Chinese-beeping-torture is the worst. I cannot move on with my life until I have ripped the innards from every alarm in the house, looking for the culprit, which is always the sixth or eighth one I've checked. My poor mother though, has seen the karma in her early support of smoke alarms. The Einstein who built the house she moved into several years ago placed a wired-in smoke alarm near the peak on the wall of their two-story living room, with only a narrow stair landing about ten feet below. Wired smoke alarms would seem like a better solution if they too did not have back-up batteries - after all, the power could be out when a fire starts. A note to contractors: even those batteries fail after several years - which my mother and her husband discovered when it started beeping - so, it would be a big help if those alarms were actually ACCESSIBLE! To get to this one required climbing a ladder placed on the landing at an alarmingly steep angle, a task most of us would rather not attempt, given our desire for the smoke alarm actually to save our lives, rather than end it. Thus, the residents had no choice but to wait two days for the services of their local fire department - who sent a fireman to make the climb and deactivate the alarm.

My mother called me shortly after the alarm had been firmly and permanently disconnected, and the haunted tone in her voice made me shudder at her recent trial. "It kept beeping..." she wailed, "Every. Twenty-six. Seconds." Though driven nearly to their wits end, their German short-hair pointer was clearly the most damaged of the three by the experience. Shortly after the beeping began he found the deepest recess of the downstairs guest room and burrowed within it, refusing to come out for anything but the quickest dash outside to relieve himself, after which he returned to his spot, trying, trying but (being a dog of very little brain) not succeeding in escaping the beeping torture. I witnessed his post-traumatic stress disorder on my next visit, when an inadvertent breaker pull caused one stray beep, and the terrified beast nearly knocked me over skidding to his designated burrow. Despite the fact that no more beeps were heard that night, the dog had to be crowbarred out of the corner of the room when I was ready to go to bed.

Really one of the stranger aspects of the low-periodicity beep torture is that it is not recognized as such by all vertebrates alike. Some friends, a family of four, invited us over for dinner once, and I noticed immediately upon crossing their threshold that they had a smoke alarm on the blink. I politely pointed it out to them, and astonishingly, the response I got was, "We know, it's been doing that for weeks now." Agog, I enquired with the grin frozen on my face, how they could stand it, and they just shrugged and said they didn't notice it after awhile. I tried to bear up under the strain, but by halfway through dinner I just couldn't keep myself from blurting out conversationally, "Wow, it's really amazing that the smoke alarm doesn't bother you." Being astute students of the subtleties of human communication, they finally got the hint, and one of them laughed as he went immediately to extract the offending battery.

I suppose that answers my question about why smoke alarms are programmed with predator-avoidance response. Those of us driven crazy by one are as likely to take a hatchet to it as a new battery (until we sigh to ourselves that maybe, just maybe it will save our lives one day), while the rest of everyone out there just can't be bothered to hunt them down (and may be selected out by unalarmed house fires). I just hope the people of Hawai`i have more success with accepting the grating chirp of the coqui than I have had with the grating chirp of a smoke alarm, because they will likely be there forever.

Labels: behavior, environment, humans, invasive species

At the risk of sounding heartless, the death of Alex the Talking Parrot last week leaves some of us, who have worked in the same department with Dr. Irene Pepperberg, a bit relieved. It was certainly bordering on irritating when those of us studying animal behavior using less glamorous species were putting in the long weekends to raise our sample sizes in order to make our work acceptable to the reviewers of actual science journals, while Dr. Pepperberg cranked out dozens of papers in such publications as the Journal of Comparative Psychology and Language Sciences, and was recruited to various appointments in science and psychology departments at the University of Arizona, MIT and Harvard using data from a single, often disagreeable, bird.

Certainly Dr. Pepperberg played the media like a fiddle, making her attractive as a "researcher" because of all the publicity she drew to that one bird. She laments Alex's passing in many respects, surely, but partly because after over 25 years of training, Alex still had not had the chance to show the world what a genius he was:

Alex could pull together a few simple concepts. Show him a group of objects and he could tell you, "What color is wood and four-corner?" or, "What shape is paper and purple?" Dr. Pepperberg was hoping to train Alex to spin his own recursions, informing her that the nut was "in the blue cup that’s on the tray" or "in the yellow box on the chair."

"I wish we had gotten further," Dr. Pepperberg wrote in an e-mail message. "We were just beginning to get him to designate things like 'in' and 'on.' "

Fortunately, though, he did last long enough to have a human's entire career built around him. Perhaps the two other parrots Pepperberg is training will achieve greater heights of language skill than Alex did. Still, one cannot help but wonder why Dr. Pepperberg never seemed to last more than a few years at a given institution. Perhaps it was her uninterest in interacting with her colleagues, which seemed to indicate that she had nothing of value to learn from such an interaction. Perhaps when the novelty of her research wore off at a given institution, the realization finally dawned that her career's work has added little of value to our body of scientific knowledge.

Sample size is a critical issue in science. Data from one individual (or even three individuals) are marginally useful at best because there is so much variation among individuals. What if an alien came to earth and collected data about the linguistic abilities of humans based on conversations with only Franklin Roosevelt? What if its data were based on conversations with a high school drop out with an IQ of 60? (or President Bush? Sorry, couldn't help that one.) Its conclusions would be quite different in the two cases.

Another problem with teaching animals English in order to draw conclusions about how their brain works is that we are testing them in a context that has no evolutionary relevance for their species. Ecologists and evolutionary biologists were interested in Alex's data, given more study about African grey parrots social structure in their natural habitat - because "language" is all about communication with others of one's same species. Unfortunately, although Dr. Pepperberg gave lip service to exploring such research directions in the future when that is what her colleagues wanted to hear, she never seemed much interested in actually pursuing that avenue (and a glance through her long reference list does not indicate any publications devoted to the parrots in the wild).

So people can argue forever about Alex's true abilities, parsing his every word and knowing glance, but what biologist can really muster any interest in the conclusion of that discussion? It will tell us nothing about Comparative Psychology, because all we have is an inadequate sample size about an animal living in a cage in a lab, interacting mostly with humans. But perhaps the Language Scientists love all the hullabaloo for inspiring passionate discussions about whether and how any species other than humans can use language. Perhaps training Alex had some purpose after all, but it was not science.

Labels: behavior, brain, statistics

A recent article about research supporting a neurological (= biological) basis for altruism panders to the alarmist view that behavior with an identifiable biological basis precludes personal responsibility, and could throw our criminal justice system into an uproar.

The first statement that shows an ignorance of sociobiology and evolution:

The results -- many of them published just in recent months -- are showing, unexpectedly, that many aspects of morality appear to be hard-wired in the brain, most likely the result of evolutionary processes that began in other species.

Why is this unexpected? In social animals, such a biological basis for morality would absolutely be expected. This is because morality governs social interactions, so animals who have evolved in the context of sociality have a biological need for it. Altruism is related to empathy, without which we cannot interact socially because we need a mechanism for assessing what another person is thinking or feeling. Those without empathy, such as autistics, are lost in the maze of unspoken rules that govern interpersonal interactions. Altruism is a way of acting on empathic information.

...some wonder whether the very idea of morality is somehow degraded if it turns out to be just another evolutionary tool that nature uses to help species survive and propagate.

The idea that "morality is somehow degraded" because it has a biological basis really has no logic to it, but it is typical of those who confuse morality with religion. Perhaps the idea is analogous to someone we like doing something nice versus someone we do not like doing it. In the latter case we assume insidious motives because we do not believe the person is truly being altruistic. But the mistake there is that there is no such thing as pure altruism, as research shows. Either altruistic acts cause us to receive tangible benefits, such as increased standing in a community, or if anonymous, provide us with pleasure (Moll et al., 2006).

Of course morality and altruism are complex neurologically because human social interactions are complex. But a biological explanation for moral behavior does not indicate a lack of need of philosophers or even religious thinkers who study moral behavior such as altruism. Humans are faced with ethical decisions nearly every day, and it is not always clear what is the altruistic way to respond, even if that is our goal. That is why religious advisors, analysts, and advice columnists are not automatically out of a job just because automatic brain function reveals our options. Our brains often do not make obvious the decisive course of action, that is, the course of action having the most positive or least negative social consequences, in the balance. Social consequences are a real biological phenomenon, because decisions affecting an individual's social standing often affect that of an entire family, which shares genes.

For example, there is the potential problem of revealing or not revealing a friend's indiscretions, such as an extramarital affair. In the short term, revealing the truth might be bad for the social group, as bonds are broken. But in the long term, the earlier such a truth is revealed, the quicker wounds may heal and the social group rebuilt. Such a decision is necessarily affected by social norms of the community, which are of course extremely variable among societies.

The article points out that "a number of experiments such as the one by Grafman have shown that emotions are central to moral thinking." Of course this is true. Grafman and his colleagues (Moll et al., 2005) make it clear that moral reasoning is a complex process that uses both reasoning and emotional centers of the brain - there is no one specific brain structure that dictates morality, but rather a series of structures that must interact in a complex way to produce a moral decision. The role of emotion is understandable because a major purpose of emotion is social navigation; for example, laughter is a way of making a social connection with another person. Solitary-living animals have no need for emotions such as love, anger, envy, pride, etc., because feeling these or acting on these invariably involves the establishment, maintenance, or alteration of a social relationship.

While several brain structures interact to produce moral reasoning, those involved can be identified specifically because specific brain damage has predictive effects on moral behavior (Moll et al., 2005). For example, damage to the prefrontal cortex at an early age prevents normal development of moral reasoning. Such people often have short-term, self-centered responses to moral dilemmas, because they have no sense of the social consequences of their actions. A different region of the cortex, the superior temporal sulcus, is required as well because it is a center of social perception, i.e. empathy, which is also required for normal moral reasoning. The limbic system, a center of basic emotional drives, also affects morality because behavior such as aggression is controlled by this area, and can become uninhibited when parts of the limbic system become damaged. Functional MRI studies also have indicated activity in the orbitofrontal cortex (behind the eyes), the anterior temporal lobes, the insula, and the anterior cingulate cortex in people processing moral dilemmas posed to them.

The claim that these discoveries mean that "society has to rethink how it judges immoral people" (according to Adrian Raine, a USC neuroscientist) is absurd. There is a minimum standard of behavior that is acceptable in a society, and this minimum exists whether or not you are psychopathic (= brain damaged in a way that impairs interpersonal interactions due to lack of empathy). If some people are physically unable to make correct social decisions, it does not mean we must treat them as equals. Serial killers are psychopaths, and whether their brain damage is physical or developmental, they cannot be allowed to move freely in society because they have no internal constraints against killing. We lock them up so that they cannot damage society further. Most people would agree that a similar situation holds for pedophiles - there seems to be increasing evidence that most are incapable of being "rehabilitated," which is not surprising; their psychopathy is likely due to brain damage - which again can be physical or developmental - that cannot be repaired. Damaged people must be isolated from society because the structure of society must be protected for the sake of the non-damaged majority.

J. Grafman says, "Some of the questions that are important are not just of intellectual interest, but challenging and frightening to the ways we ground our lives. We need to step very carefully." Not at all. This information is simple and reasonable when understood in terms of maintaining a functional society.

An interesting moral phenomenon in humans involves the altruism of helping someone near and dear to you versus helping people in distant countries that you will never visit. The neuroscientist/philosopher Joshua Greene, interviewed in the article, gets the implications of this wrong:

"We evolved in a world where people in trouble right in front of you existed, so our emotions were tuned to them, whereas we didn't face the other kind of situation," Greene said. "It is comforting to think your moral intuitions are reliable and you can trust them. But if my analysis is right, your intuitions are not trustworthy. Once you realize why you have the intuitions you have, it puts a burden on you" to think about morality differently.

Yes, we evolved in a non-global world, and our knowledge of the plights of people around the world sets humans apart from other social animals. But that is not the point. What matters is that any type of altruism affects one's standing either in society, or to oneself. Our higher reasoning ability convinces us that faraway starving children are as important as the starving children next door - even as our emotions tell us otherwise - but this does not make our intuitions untrustworthy, it just adds potential complexity to the moral decisions we make. If one is a member of a church, for example, where such generous behavior is valued, it increases or maintains one's social standing to give to the needy in faraway places, it makes sense to do it. For many people, "charity begins at home" is an acceptable societal standard, and thus there is no burden to think about morality differently. Undamaged brains can still rely on their moral intuitions, and navigate their social world successfully.

Of course the different details of morality across cultures require us to be flexible in their moral reasoning. The social brain must adapt to local social conditions to successfully reproduce. This creates difficulties in a globalized world in which we not only are aware of the different moral values in different societies, but people from those different societies interact daily, not only in person, but probably more important these days, over the internet. To use an extreme example, people from societies that support individual rights for women have worked hard to stop what to us are sickening cultural practices such as female genital mutilation. Any Western woman is horrified by the practice with good reason - it not only is such an extreme example of oppression of women by men, which goes against our stated values (values that were hard won and still being fought for even in our "enlightened" society), but the long term health consequences are often dire. Yet efforts to eliminate the practice are often derailed by the women of those cultures themselves, because if they do not accept the ritual mutilation, they will be rejected by their society (and will not reproduce successfully there). It is nearly impossible to end such traditions by force. The values rejecting them must be inculcated in enough of the local population to the point where it becomes socially acceptable not to undergo the mutilation.

A similar example closer to home is the explanation of why most battered wives return to their husbands over and over again, contrary, it seems, to all reason. But in the cultures (and subcultures) in which wife-beating is common, breaking the cycle is so difficult because if a woman leaves her husband she often must give up her entire social group as well (and she often cannot fathom that it would be possible to become part of another social group, simple as that may seem in the abstract). Going it alone under such circumstances is contrary to our very nature as social beings.

It is completely natural for everyone to believe that their society's cultural norms are superior to everyone else's, because they know from experience that following those cultural norms make them successful. Of course though, if the same behavior is transferred to a society with different cultural norms, the result can be disaster. It is this naive sense of superiority (also held by most religious groups) that creates solutionless predicaments such as the current one in Iraq.

References

Moll, J., Krueger, F., Zahn, R., Pardini, M., de Oliveira-Souzat, R. & Grafman, J. (2006) Human fronto-mesolimbic networks guide decisions about charitable donation. Proceedings of the National Academy of Sciences of the United States of America, 103, 15623-15628.

Moll, J., Zahn, R., de Oliveira-Souza, R., Krueger, F. & Grafman, J. (2005) The neural basis of human moral cognition. Nature Reviews Neuroscience, 6, 799-809.

Labels: behavior, brain, empathy, humans, morality, sociality

Either the media or the public (seems to be a bit of a chicken and egg question) seems to want every problem to be defined in black and white terms. If you are Josephine Public, this makes sense because we all would love easy answers to the vexing problems that confront society, even as we know deep down that there usually aren't any. The media aggravates this problem with their desperation to oversimplify stories for fro yo-easy consumption, and yet to create controversy at the same time. It accomplishes both to declare emphatically that if you have a nagging weight problem, it is not your fault, it is all in the genes, while other media outlets exhort us to eat less and exercise more, so we can enjoy thin, fulfilling lives.

There are a few reasons why the genetics of obesity are newsworthy. First, many people believe the obese among us have suffered enough, both from their condition, and from the finger wagging of the thin, and all the chastising is not helping people regain a healthier weight. Second, plenty of research papers do show unequivocally that there is indeed a strong genetic component to weight set point in people. This is nothing new, it has been documented in research journals since the 1980's at least (e.g. Stunkard et al., 1986, in which body mass indices (BMI) of adopted children were compared to those of biological vs. adoptive parents; and Stunkard et al., 1990, in which BMI of identical and fraternal twin sets reared together vs. apart were measured). Third, we live in a time of increasingly rapid advances in biological knowledge, especially in genetics, which has led the media to promote the romantic notion that all problems can be traced to genetics solved by genetic tinkering. With the massive failures in gene therapy of the 1990s all but forgotten, one of the biggest political footballs has become the assumed silver bullet of stem cell research.

There is no reason not to conduct any sort of genetic research; it will always provide information. However, geneticists are reductionists and, because of what they do, overly enamored of the "nature" side of the nature/nurture debate. Our recent breakthroughs in genetics, coupled with the politically rightward trajectory of the western world, has recently given "nature" hugely disproportionate emphasis. These cultural and political swings occur back and forth over time. But just as the political moderates are drowned out by the extremists on both sides, so are those of us pointing out that nearly all traits observed in biological organisms, including humans, are a result of the interaction of genetics with environment - the nature/nurture dichotomy is a myth.

The message is so at odds with the popular conception of weight loss — the mantra that all a person has to do is eat less and exercise more — that Dr. Jeffrey Friedman, an obesity researcher at the Rockefeller University, tried to come up with an analogy that would convey what science has found about the powerful biological controls over body weight...Those who doubt the power of basic drives... might note that although one can hold one’s breath, this conscious act is soon overcome by the compulsion to breathe...

Such dramatic statements certainly make for good copy. But what the story's author, and perhaps interviewees failed to mention is the recent increase in average weight and obesity in both western and developing countries that has been well documented (as reported by the multinational Organisation for Economic Cooperation and Development):

...obesity rates have increased in recent decades in all OECD countries for which trend data is available. There remain however notable differences in obesity rates across countries. In the United States, the obesity rate among adults (30.6% in 2002) is the highest in OECD countries, followed by Mexico (24.2% in 2000) and the United Kingdom (23% in 2003). Obesity rates in Continental European countries are lower, but are also rising.

Are those with a genetic disposition for getting fat reproducing at a higher rate around the world than those who are thin? It is unlikely. And why are there lower obesity rates in other western nations and developing countries? There are several major correlates of obesity rates over time and space: fast food, television, and cars (Cheng, 2005), which tend to go together. But it is possible that car ownership alone is enough to cause the weight effect (Bell et al., 2002, from their abstract):

Our main outcome measure was current obesity status and the odds of becoming obese over an 8-year period. In 1997, 84% of adults did not own motorized transportation. However, the odds of being obese were 80% higher (p<0.05) for men and women in households who owned a motorized vehicle compared with those who did not own a vehicle. Fourteen percent of households acquired a motorized vehicle between 1989 and 1997. Compared with those whose vehicle ownership did not change, men who acquired a vehicle experienced a 1.8-kg greater weight gain (p<0.05) and had 2 to 1 odds of becoming obese.

Meanwhile, in European countries, not only do fewer people own cars than in the U.S., but people generally have a different relationship with food there too, tending much more to buy locally, non-mass produced food. The U.S.'s penchant for pursuing the efficiency of mass production may be brilliant in many contexts, but the industrialization of farms and food production is a disaster for human health. Forgetting the reliance on low-nutrition packaged food (no matter how much the label screams "healthy!" at you), we also have a system that, thanks to the U.S.D.A.'s grading system, which ignores nutrition and taste in favor of appearance, makes even "fresh" food unpalatable. It is no wonder that most Americans prefer Big Macs to string beans.

The genes/environment interaction is well known for many species of organisms, and can be referred to as "phenotypic plasticity." For example, there is a species of caterpillar whose appearance depends on when it is born, either spring or summer. All caterpillars feed on oak trees, but in the spring they looks like oak flowers, while in the summer they resemble oak twigs. The difference is striking. There are no genetic differences between the two types - their form depends completely on diet, i.e. whether it consists of flowers or leaves (Greene, 1996). Similarly, there could be two people who both have the genetic disposition to be fat. One that lives a "western" lifestyle revolving around fast food, television, and automobiles, is likely to be fat. The other, living as a subsistence farmer in a town with no electricity and only bicycles and feet for transportation, is not as likely to be fat. Those without the genetic disposition for putting on fat would be thin under either condition.

The obsessive focus by some scientists and journalists on genetics, and by others on environment, is blinding us to the importance of the interaction of the two. Those in the media emphasizing exercise are well-intentioned, but misguided. Human bodies predisposed to putting on a lot of weight are probably not going to be much affected by an hour of "cardio" three or four times a week. We have to take a step back and imagine what it is our bodies are designed to do. In a non-technological world, our bodies are designed to walk - a lot. Some mammals are selected for lying around most of the time, with short bursts of speed and strength occurring at occasional intervals (e.g. lions and other large predators). Other migratory mammals, such as grazers, can keep up a moderate pace for a long time, but must spend a lot of their time eating because they eat a low-energy food.

What humans appear to be designed for is walking and running over long times and distances. There are legends of American Indian lacrosse games on miles-long fields lasting for days, and there was a time when native Mexicans were known for their extraordinary running ability (Dyreson, 2004). Some African hunters follow their game long distances for days. More examples can be found. But because humans are designed for locomotion by foot, "exercise" needs to be better defined. Getting your heart rate up once in awhile, with the great majority of the time being spent at rest, is simply not what humans are designed to do, and thus our bodies will not be in the proper balance of nutrient use vs. storage. Obesity research makes it clear that it doesn't necessarily matter how many calories you burn while you are exercising. Weight is much more complex than "calories in, calories out." A common big difference between those who are thin and those who are fat is that for the thin people, walking is incorporated to a much larger degree into their daily life.

What can someone living a western lifestyle do? I am not a dietitian or a doctor, but the research suggests that if you are someone who has a tendency to be overweight, whose diets work for a while but never for good, who has tried working out at the gym to no avail, the only way to lose weight over the long term is to make sweeping lifestyle changes, that include a lot of walking every day, in addition to periodically more strenuous exercise. I am not someone who is naturally thin. A post-pregnancy regimen that got me back into shape quickly was at least 4-5 miles of walking per day, usually weight(=baby)-bearing, plus more strenuous workouts 4-5 days a week (if I reduced that to just 3 days a week, it kept me in a holding pattern, but I didn't make any progress on my conditioning).

Maybe you can't walk to work from your house, but maybe you could find a place to park two miles away. But maybe your commute's too long already, though, to add an hour and a half to it. Maybe you are spending so much time away from home, or it takes so much extra effort to find real food, that it seems unthinkable to prepare anything but pre-packaged foods. Unfortunately we have developed our way into a lifestyle corner that is not amenable to staying within the normal parameters for being human.

The media, government, and non-governmental organizations can talk about genes and diet and exercise until they are blue in the face. As long as we continue to build exurban communities with zoning that requires complete dependency on cars to do the briefest errand, often to the fast-food place which is much closer and more accessible than a local farmer's market, a lot of people will continue to be fat. But despite the realities of modern U.S. life, if we do not find a way to change the policies that lead to these destructive lifestyles, we are dooming many of ourselves, and our children, to a lifetime struggle with health. Instead of living our lives, many more of us will be dealing with constant health problems, which all of us will pay for, one way or another. Fortunately in the U.S., it is truly possible to effect substantive change at the lowest local level. If we do not, Dr. Friedman, we only have ourselves to blame, genes be damned.


References

Bell, A.C., Ge, K., Popkin, B.M. (2002). The road to obesity or the path to prevention: motorized transportation and obesity in China. Obesity Research 10, 277–283.

Cheng, T.O. (2005) Fast food, automobiles, television and obesity epidemic in Chinese children. International Journal of Cardiology, 98, 173-174.

Dyreson, M. (2004) The foot runners conquer Mexico and Texas: Endurance racing, indigenismo, and nationalism. Journal of Sport History, 31, 1-31.

Greene, E. (1996) Effect of light quality and larval diet on morph induction in the polymorphic caterpillar Nemoria arizonaria (Lepidoptera: Geometridae). Biological Journal of the Linnean Society, 58, 277-285.

Stunkard, A.J., Harris, J.R., Pedersen, N.L. & McClearn, G.E. (1990) The body-mass index of twins who have been reared apart. New England Journal of Medicine, 322, 1483-1487.

Stunkard, A.J., Sorensen, T.I.A., Hanis, C., Teasdale, T.W., Chakraborty, R., Schull, W.J. & Schulsinger, F. (1986) An adoption study of human obesity. New England Journal of Medicine, 314, 193-198.

Labels: behavior, health, humans

Trap-jaw ants are the venus fly traps of ants, in the tropical/subtropical genus Odontomachus. They are some of the most incredible animals on earth, because of the speed at which they can snap their jaws together to snatch their prey. The species at left, O. clarus, is one I encountered in Arizona. Like many desert animals, these ants like to hunt at night, and it was common to see them milling about on the University of Arizona campus in the glow of the street lights. The workers are striking to see because they walk about with their huge jaws in the open position. In the picture you can barely see tiny trigger hairs, which are similar to trigger hairs in venus fly traps. Because this is an animal, though, there are large jaw muscles which contract like coiled springs to hold the jaws open. When there is pressure on a trigger hair, the effect is like unhooking a latch (think of a mousetrap), and the jaws explosively close on their prey, at a nearly unimaginable speed:

"Biologists clocked the speed at which the trap-jaw ant, Odontomachus bauri [at right], closes its mandibles at 35 to 64 meters per second, or 78 to 145 miles per hour - an action they say is the fastest self-powered predatory strike in the animal kingdom. The average duration of a strike was a mere 0.13 milliseconds, or 2,300 times faster than the blink of an eye."

To record the entire motion requires filming the ants at 50,000 frames per second, rather than the usual 24.

In their paper published last August (Patek, S.N., J.E. Baio, B.L. Fisher, and A.V. Suarez, 2006. Multifunctionality and mechanical origins: Ballistic jaw propulsion in trap-jaw ants. Proceedings of the National Academy of Sciences 103: 12787-12792), researchers added to this incredible story by discovering an additional purpose of the trap jaws. They first calculated the force of the mandibles: "...a single mandible could potentially generate a force that is 371-504 times the ant's body weight." Then they documented a previously unknown use for this force in O. bauri: self-propulsion.

You must watch these videos to fully appreciate this behavior. But, to summarize, by snapping their jaws against a hard surface, O. bauri achieves "heights up to 8.3 centimeters and horizontal distances up to 39.6 centimeters. That roughly translates, for a 5-foot-6-inch tall human, into a height of 44 feet and a horizontal distance of 132 feet." Of course, whenever comparisons are made between insects and humans, the former come out looking like Schwarzeneggers to the hundredth power. This is because such comparisons do not take into account the effects of scaling. The insect world, with the same gravity and atmosphere as we have, but with exoskeletons and light weight, is a very different place (which is a topic for a later time). Everyone knows you can drop an insect from great height and it will emerge unscathed. This is very useful if your escape route is flying eight times your body length straight up into the air.

To see some amazing biodiversity in action, watch the videos.


More incredible ant pictures are posted at myrmecos.net!

Labels: ants, behavior, biodiversity, cool bugs, ecology, insects

A Science Times story about the condition known as "dissociative amnesia" today jarred a memory I have of one chapter of a friend's extremely colorful life. My friend is in her 80's and was married four times; only the final marriage lasted for a significant time, and only it could be described as fairly normal. Her first marriage story can only be described as astounding.

My friend "Annie" got married for the first time near the start of the U.S. involvement in WWII. Her husband became a soldier, but never made it overseas - he was involved in a train accident in the U.S. and suffered brain damage and a long recovery. How Annie coped during this period with no money and a couple of small children is a story itself (it never occurred to her that she could get some assistance from Uncle Sam), but eventually her husband recovered enough to work for the U.S. mint as an engraver after the war. Life went on for a few years but Annie wasn't entirely happy because her husband was starting to show, in her mind, undue aggression toward her oldest son. She was concerned that sometime he might go too far and hurt her son, but didn't know what to do about it.

The problem ended up solving itself, because one day Annie's husband never came home from work. No one had a clue where he was. She tried for awhile to locate him but the effort was a bit halfhearted because in truth, she was relieved for her kids' sake. She still found it quite odd, though, that he would leave for good without even a word to her. She eventually obtained a divorce due to her abandonment, but his disappearance remained a mystery - no friends or family members knew where he went.

Something like 20 years or more passed before the mystery was solved. The ex-husband's sister was walking along in Seattle one day, and was shocked to see him on the street. She grabbed him and started talking, and it was only at that point that he himself remembered anything of his life 20 years before. The day he disappeared, he had simply forgotten everything about his life at the time, to the point of not even knowing where he was or how to get home. I know no details of how he dealt with his situation at the time, but at the time he was rediscovered, he had built an entirely new life with a wife and kids without remembering a thing about his original life until the day he saw his sister, when it came back to him.

Eventually, he travelled to visit Annie and her (fourth and final) husband, but Annie's oldest son refused to talk to him; Annie could not convince him that his father had abandoned him through no fault of his own. By that time enough years had passed that Annie, happy in her current family, was philosophical and did not feel any emotional baggage in meeting him; she did so mainly out of curiosity, and understood that what had happened was some sort of strange by-product of the train accident. She and her husband continued a friendly correspondence with her ex and his family for a number of years.

I had never heard of this type of amnesia before or since hearing this amazing story from Annie, until reading the above article. I'm sending her a copy! Here is the
Merck manual description of the disorder.

My main reaction is that this must happen more than is recognized, because Annie's ex was able to build a whole new life, and never would have known what happened to him if he hadn't happened to run into his sister - imagine the odds of that! I do not know if he ever told a doctor about his problem or not, but he coped with it rather well. Perhaps it would be harder in today's world where ID numbers are so ubiquitous. But if I ever hear again about someone abandoning their family without a trace, I would have to wonder...

Labels: behavior, brain

Recent concern about apparent die-offs in bees apparently has now led to speculation that cellphone radiation is the cause for bee disappearance. Instapundit has weighed in, questioning with well deserved skepticism the validity of this claim.

Because I am a scientist, I do not try to establish validity of such reports via Google, but via Web of Science, the search engine that encompasses academic literature, both peer-reviewed and not. As far as I am concerned, until data have been published in peer-reviewed literature, any fantastic "scientific" claims are just clamors for attention.

There is no information yet in the scientific literature regarding possible causes of CCD or "colony collapse disorder" as some have tagged the syndrome of the disappearing bees. This is not too surprising, because it appears to be a fairly recent phenomenon, but I guarantee you that because the USDA supports several Bee Research Laboratories in the western U.S., this problem, if genuine, is being addressed by qualified government scientists as I write (if all the bee lab guys I used to know weren't long retired from the lab, I would call one now to get his take on it).

The mere fact that the U.S.D.A. has labs of bee scientists confirms that domesticated honey bees are indeed important to the pollination of crops in the U.S. But as I pointed out in my last post on the topic, they are by no means the only species of pollinator out there. So don't expect any food shortage panics anytime soon.

What of the cell radiation theory then? Cell radiation has been a human health concern for quite some time, and thus the literature on this topic is quite robust. Some studies (but not others) have found increased cell apoptosis (cell death that is orderly - as opposed to sudden and widespread) due to exposure to cell radiation, but even this doesn't mean we should necessarily be alarmed, because all these studies were performed on cell cultures (in vitro), not on real people using cell phones in a usual manner (in vivo). A recent paper (Valberg, P.A., van Deventer, T.E. & Repacholi, M.H. (2007) Workgroup report: Base stations and wireless networks-radiofrequency (RF) exposures and health consequences. Environmental Health Perspectives, 115, 416-424.) examines evidence that radio-frequency radiation (including cell phones) affects actual human health adversely, and concludes that there is no evidence that it does so. In fact, the authors point out (from the abstract):

The possibility of RF health effects has been investigated in epidemiology studies of cellular telephone users and workers in RT occupations, in experiments with animals exposed to cell-phone RF, and via biophysical consideration of cell-phone RF electric-field intensity and the effect of RF modulation schemes. As summarized here, these separate avenues of scientific investigation provide little support for adverse health effects arising from RF exposure at levels below current international standards. Moreover, radio and television broadcast waves have exposed populations to RF for > 50 years with little evidence of deleterious health consequences. Despite unavoidable uncertainty, current scientific data are consistent with the conclusion that public exposures to permissible RF levels from mobile telephony and base stations are not likely to adversely affect human health.

Here is a table from the paper comparing all the sources of RF we are exposed to (sorry about the low resolution):

So my advice is, chat away until further notice - with the caveat that out of caution, avoid giving cell phones to young kids because developing brains are certainly more sensitive to environmental effects than grown ones, models suggest that child heads absorb EM radiation more than adult heads (De Salles, A.A., Bulla, G. & Rodriguez, C.E.F. (2006) Electromagnetic absorption in the head of adults and children due to mobile phone operation close to the head. Electromagnetic Biology And Medicine, 25, 349-360.). Obviously, if anyone had found major health effects yet there would have been a massive response to deal with it by some country.

Back to the bees though. Different species will not necessarily be affected the same way as humans, especially such distantly related groups such as insects, but as of yet I, as an entomologist who does not specialize in bees, doubt that cell radiation is causing CCD. The article quotes some one knowledgeable about cell radiation, not insects, in asserting the likelihood that it does. Most important, bees navigate primarily via polarized light, which is in a completely different part of the EM spectrum from radio waves. How radio waves could possibly impact their use of light for navigation (any more than it does humans' use of light for navigation) is at best nonintuitive, so I would never believe it until I saw the published paper showing me the evidence. I am not holding my breath for that paper to appear.

Other references:

Erogul, O., Oztas, E., Yildirim, I., Kir, T., Aydur, E., Komesli, G., Irkilata, H.C., Irmak, M.K. & Peker, A.F. (2006) Effects of electromagnetic radiation from a cellular phone on human sperm motility: An in vitro study. Archives Of Medical Research, 37, 840-843.

Joubert, V., Leveque, P., Cueille, M., Bourthoumieu, S. & Yardin, C. (2007) No apoptosis is induced in rat cortical neurons exposed to GSM phone fields. Bioelectromagnetics, 28, 115-121.

Remondini, D., Nylund, R., Reivinen, J., de Gannes, F.P., Veyret, B., Lagroye, I., Haro, E., Trillo, M.A., Capri, M., Franceschi, C., Schlatterer, K., Gminski, R., Fitzner, R., Tauber, R., Schuderer, J., Kuster, N., Leszczynski, D., Bersani, F. & Maercker, C. (2006) Gene expression changes in human cells after exposure to mobile phone microwaves. Proteomics, 6, 4745-4754.

Thorlin, T., Rouquette, J.M., Hamnerius, Y., Hansson, E., Persson, M., Bjorklund, U., Rosengren, L., Ronnback, L. & Persson, M. (2006) Exposure of cultured astroglial and microglial brain cells to 900 MHz microwave radiation. Radiation Research, 166, 409-421.

Zhao, T.Y., Zou, S.P. & Knapp, P.E. (2007) Exposure to cell phone radiation up-regulates apoptosis genes in primary cultures of neurons and astrocytes. Neuroscience Letters, 412, 34-38.

Labels: bees, behavior, environmental toxins

Apparently the internet age has been around long enough now for psychologists and neurologists to study behavior [subscription req'd] associated with our relatively recent and speedy forms of communication. This is a realm in which the part of our behavior designed to guide us through complex social interactions is being short-circuited - hence, flame wars.

Why? The explanation is at least partly contained in the review paper: J. S. Beer and K. N. Ochsner, 2006. Social cognition: A multi level analysis. BRAIN RESEARCH 1079:98-105.

Successful social interactions depend on a constant flow of information between the people interacting. My interpretation of the thoughts and emotions of a person I am talking to immediately affects not only what I say to that person, but the words I choose to say it, and my body language as well. But it is more complex than that - my interaction with the person is also dependent on a multitude of biases I bring to the conversation, including the memory of past events associated with that person, my opinion of the person based on what others have told me, and expectations based on my internal "golden rule," which basically is saying to me, "this is how I would react to what I am saying, so this person will react that way too."

There are two major reasons that the internet affects this interaction, the first of which is explained in the article. Without getting any feedback from a person about how what we are saying affects them, there is no external mechanism filtering what we say. I think it is safe to say that an average person feels reluctance to hurt another person's feelings, if these people are interacting face-to-face. We don't feel that same reluctance over the wires, because we don't have to see that person react. When we have no direct perception of the impact we make, our 'mirror neurons' are not going to be firing. These neurons connect our interpretation of another person's emotions with our own emotional center; i.e. they give us empathy, which is exactly what allows us to be successful as a social species. (More on empathy is discussed in a previous post, and look for more in future posts - the biology of sociality is one of my big interests, and in humans, empathy plays a huge role.)

The second reason the internet age has accelerated problems in social interaction is that it allows people from cultures all over the world to interact to an unprecedented degree. Interactions between people with different cultural behavioral norms will often cause problems when those interacting fail to acknowledge the conflicting cultural norms involved. Frankly, this happens all the time, I believe because humans naturally identify with a particular culture, so that we can properly navigate within that culture. Our brains seem to be designed to mimic the perceived cultural norms during development. Just watch how your kids imitate you, other adults, and other kids - which these days can be a real headache for parents because of the cultural mixing we have in many places, which is again due to accelerating technology, in this case, ease of transportation. I'm guessing that this same problem has a role in some incidents of road rage and other spontaneous acts of violence between otherwise average citizens. This is also one of many reasons there will never be an end to war, at the same time that most people honestly do seem to get along fine with people they know face-to-face. That is not wussy liberal mumbo-jumbo. It's simply biology.

The situation is not helped by every-day situations that encourage anti-social behavior. For example, most frequent flyers and users of health insurance know that the squeaky wheel gets the grease - the business model in some industries is clearly only to help people that literally scream the loudest, because the alternative would be to help everyone, and that would just be too expensive. And certainly Michelle Malkin knows exactly what she's doing when she writes her over-the-top posts: those that thwart societal norms of polite interaction are identified and vilified publicly by the group they offend, which translates into the well known marketing adage: There is no such thing as bad publicity. (Those that support the Malkins of the world of course are those that either offend to the same degree, or would if they didn't feel so hampered by polite social discourse.)

Of course, as discourse becomes ever more vitriolic (doesn't every generation say that?), you have to be that much more offensive to get attention. Praise Allah that we have the blogosphere to air our increasingly outrageous grievances with others. And people ask why the country (and the world?) has gotten more partisan and petty? Instead of cultural mixing, both physical and virtual, leading to a better understanding of others' points of view, it seems it gives us more opportunities to designate "us" vs. "them," whether one is talking about race, religion, politics, etc. It appears to be human nature to circle the wagons in order to protect the home group from "other" - the consequences of this behavior simply have become more global with time.

When will they ever learn? Never.

Labels: behavior, empathy, humans, sociality

We have two male black and white cats (also known as tuxedo cats, or holsteins), shown here. The older one, Ippy, is well known in the neighborhood for playing with kids in the park a block away, and following people walking by our house to the grocery store across the park, waiting for them outside, and walking with them back to our house. Ippy was almost a year old when he adopted the younger, Tacaribe, without involving us in the decision (Tacaribe had two cameos on Tigerhawk soon after Ippy adopted him).

We had already discussed the interesting behavior of the black-and-white males with our vet, who told us that every single one she had run across had a very playful, mischievous and outgoing personality. She thinks it is much more pronounced in the males than the females. My husband's family had a black-and-white that was very similar to Ippy in his personality. He was people-centered rather than place-centered, which is uncommon in cats (a solitary species). For example, when they traveled and stopped in hotel for the night, they could put him out and he would come back to their room in the morning. We have come to the conclusion that the trait involved with such behavior is probably one that causes neoteny, or retention of juvenile (kitten) behavior in the adult.

This is not a particular breed of cat; Ippy and Taca have very different body types, and really only are similar in their coloring and spunky behavior. Looking in a big cat book at a book store once I noticed that many listed breeds had a black-and-white form, generally distinguished by a mostly black cat with white feet, chest/belly, and often forehead spot. For some reason, this behavior seems to be associated with this particular black-and-white coloring. Although this might seem a strange association, it is not unheard of. In Drosophila, the yellow gene, which is involved with the production of melanin (pigmentation) in the flies, also has neurological effects. Mutant males without the normal yellow gene have lower mating success than normal males, and there are apparently effects on larval foraging as well.

Behavioral neoteny in flies wouldn't really make much sense, because flies undergo complete metamorphosis - there wouldn't really be a way for an adult to act like a larva. But it is intriguing that there seems to be a similar connection between pigmentation and behavior in my cats.

Labels: behavior, cats, flies, genetics