The Scientific Explanation Thread

[lostpunk5545]

Research suggests that ADHD is not so much a disorder but has an evolutionary precedent. Guess it doesn't help frustrated parents much but it's interesting to know.

Did hyperactivity evolve as a survival aid for nomads?

Impulsivity and a short attention span may be the bane of every parent with a hyperactive toddler, but those same traits seem to help Kenyan nomads keep weight on.

A gene mutation tied to attention deficit hyperactive disorder (ADHD) is also associated with increased weight among a chronically undernourished group of nomads called the Ariaal. Notably, the mutation offers no such benefit to a cousin population that gave up the nomadic lifestyle in the 1960s.

The nomads' active and unpredictable life centred on herding might benefit from spontaneity, says Ben Campbell, an evolutionary anthropologist at the University of Wisconsin at Milwaukee, US, who was involved in the new study.

"If you are a nomad then you ought to be little more impulsive than if you are settled," he says. "You should be a little quicker on the trigger."

Different lifestyles

The Ariaal are an isolated group of nomads who wander around northern Kenya, herding cows, camel, sheep and goats. Encouraged by Christian missionaries in the 1960s, some members settled in the same region and started relying on agriculture for some of their food.

The nomads and the settled groups still interact and intermarry, but they live drastically different lifestyles. "The nomads are always doing something. They are always walking to herd their animals," Campbell says, while settled Ariaal tend to be sedentary.

A previous study found that nomadic cultures around the world tend to have the same mutations, which determines the brain's response to a pleasure-delivering chemical called dopamine and is linked to impulsivity and ADHD.

Campbell and his colleague Daniel Eisenberg, of Northwestern University in Evanston, Illinois, US, looked for the mutation in 87 settled and 65 nomadic Ariaal men.

About a fifth of the men from each group had the mutation. However, their physiques differed. Nomads with the mutation, which is in the gene called DRD4, tended to have slightly higher body-mass indexes and more muscles than nomads without the mutation – though both would be considered undernourished by Western standards. No such difference existed in the settled Ariaal.

Lean times

Why the mutation isn't more common is a mystery, says Eisenberg. Another study found the impulsive variation in about 60% of native South Americans, but only 16% of Caucasian Americans. "It might be that there is a niche for a few people with more impulsive behaviour, but when there are too many of them those niches are filled," he says.

Also unexplained is how a gene linked to ADHD promotes greater body weight in nomads, and not village dwellers. Campbell speculates that a short attention span and penchant for risk taking could benefit nomads who don't know where the next meal will come from.

However, the mutation could also make food more gratifying, or it might affect how the body converts calories to kilograms. "We really don't know," Campbell says.

The mutation "predisposes you to be more active, more demanding, and not such a pleasant person," says

Henry Harpending, an anthropologist at the University of Utah in Salt Lake City, also in the US. "You probably do better in a context of aggressive competition." In other words, in lean times, violent men may feast while passive men starve.

http://www.newscientist.com/channel/being-human/human-evolution/dn14100-did-hyperactivity-evolve-as-a-survival-aid-for-nomads.html?feedId=human-evolution_rss20

 

[lostpunk5545]

Religion literally a figment of our imaginations? I like that theory

Religion a figment of human imagination

Humans alone practice religion because they're the only creatures to have evolved imagination.

That's the argument of anthropologist Maurice Bloch of the London School of Economics. Bloch challenges the popular notion that religion evolved and spread because it promoted social bonding, as has been argued by some anthropologists.

Instead, he argues that first, we had to evolve the necessary brain architecture to imagine things and beings that don't physically exist, and the possibility that people somehow live on after they've died.

Once we'd done that, we had access to a form of social interaction unavailable to any other creatures on the planet. Uniquely, humans could use what Bloch calls the "transcendental social" to unify with groups, such as nations and clans, or even with imaginary groups such as the dead. The transcendental social also allows humans to follow the idealised codes of conduct associated with religion.

"What the transcendental social requires is the ability to live very largely in the imagination," Bloch writes.

"One can be a member of a transcendental group, or a nation, even though one never comes in contact with the other members of it," says Bloch. Moreover, the composition of such groups, "whether they are clans or nations, may equally include the living and the dead."

Modern-day religions still embrace this idea of communities bound with the living and the dead, such as the Christian notion of followers being "one body with Christ", or the Islamic "Ummah" uniting Muslims.

Stuck in the here and now

No animals, not even our nearest relatives the chimpanzees, can do this, argues Bloch. Instead, he says, they're restricted to the mundane and Machiavellian social interactions of everyday life, of sparring every day with contemporaries for status and resources.

And the reason is that they can't imagine beyond this immediate social circle, or backwards and forwards in time, in the same way that humans can.

Bloch believes our ancestors developed the necessary neural architecture to imagine before or around 40-50,000 years ago, at a time called the Upper Palaeological Revolution, the final sub-division of the Stone Age.

At around the same time, tools that had been monotonously primitive since the earliest examples appeared 100,000 years earlier suddenly exploded in sophistication, art began appearing on cave walls, and burials began to include artefacts, suggesting belief in an afterlife, and by implication the "transcendental social".

Once humans had crossed this divide, there was no going back.

"The transcendental network can, with no problem, include the dead, ancestors and gods, as well as living role holders and members of essentialised groups," writes Bloch. "Ancestors and gods are compatible with living elders or members of nations because all are equally mysterious invisible, in other words transcendental."

Nothing special

But Bloch argues that religion is only one manifestation of this unique ability to form bonds with non-existent or distant people or value-systems.

"Religious-like phenomena in general are an inseparable part of a key adaptation unique to modern humans, and this is the capacity to imagine other worlds, an adaptation that I argue is the very foundation of the sociality of modern human society."

"Once we realise this omnipresence of the imaginary in the everyday, nothing special is left to explain concerning religion," he says.

Chris Frith of University College London, a co-organiser of a "Sapient Mind" meeting in Cambridge last September, thinks Bloch is right, but that "theory of mind" – the ability to recognise that other people or creatures exist, and think for themselves – might be as important as evolution of imagination.

"As soon as you have theory of mind, you have the possibility of deceiving others, or being deceived," he says. This, in turn, generates a sense of fairness and unfairness, which could lead to moral codes and the possibility of an unseen "enforcer" - God – who can see and punish all wrong-doers.

"Once you have these additions of the imagination, maybe theories of God are inevitable," he says.

http://www.newscientist.com/channel...imagination.html?feedId=human-evolution_rss20

 

[Rated E]

Random thought that occurred when reading the ADHD article:

Wouldn't it be weird / cool / whatever if at some point we began to evolve towards simplification of mental processes.

It seems like things such as anxiety and depression are a result of our higher order mental functioning. Our tendency to not live in the here and now, but instead reflect on and analysis on the here and now. This reflection and analysis can be rewarding, it can also go too far and cause things like anxiety. For example, anxiety can arise from over thinking a situation, hypothesising and considering so many possible outcomes in any given situation, that fear of failure and what might go wrong inevitable occurs. With the old "just do, don't think about it" sentiment seeming to provide a less stressful approach to the world.

Anyway I just thought it would be interesting if humans began to breed out their higher order functions (anxiety, stress -> lowered sex drives, and most likely less success with mating).

Of course this idea assumes too much a strong correlation between higher order reasoning and anxiety or stress. As, considering possibilities and analysis or reflection need not always, or even most of the time, cause stress. Since positive outcomes might also be considered just as much as potentially negative ones, and reflection might provide insight as to better and more well planned decision making.

 

[lostpunk5545]

The only problem is that I don't think stress and anxiety are traits that are going to stop anyone getting laid. Especially seeing as on a chemical level sex alleviates anxiety and depression and thus is desirable to seek out.

To quote Bad Religion, "People making babies sometimes just to escape."

 

[Rated E]

Yea indeed. It was just a passing tangent.

 

[endlesseulogy]

Random thought that occurred when reading the ADHD article:

Wouldn't it be weird / cool / whatever if at some point we began to evolve towards simplification of mental processes.

It seems like things such as anxiety and depression are a result of our higher order mental functioning. Our tendency to not live in the here and now, but instead reflect on and analysis on the here and now. This reflection and analysis can be rewarding, it can also go too far and cause things like anxiety. For example, anxiety can arise from over thinking a situation, hypothesising and considering so many possible outcomes in any given situation, that fear of failure and what might go wrong inevitable occurs. With the old "just do, don't think about it" sentiment seeming to provide a less stressful approach to the world.

Anyway I just thought it would be interesting if humans began to breed out their higher order functions (anxiety, stress -> lowered sex drives, and most likely less success with mating).

Of course this idea assumes too much a strong correlation between higher order reasoning and anxiety or stress. As, considering possibilities and analysis or reflection need not always, or even most of the time, cause stress. Since positive outcomes might also be considered just as much as potentially negative ones, and reflection might provide insight as to better and more well planned decision making.

Good post. Hominids (from anatomically modern humans, homo erectus and to our yet to be discovered ancestors since our last common ancestor with the great apes) have been susceptible to a high degree of analytical behavior and number crunching. Higher order functions are what separates us from amoeba. The size of our neocortex means we are morphologically structured to perform complex tasks. I don't think its possible, (while maintaining the current mass of our neocortex) to root out these capabilities while still maintaining a high degree of intelligence. However, this does not mean, sometime in the future, humans won't be able to somehow control this erratic thinking - causing anxiety; by switching it off. Hypothetically, a mental mehanism may be selected for in the futuristic gene pool that may make it possible for us to cope with stress by merely thinking it away. One must always put this issue in a little bit of chronological perspective. It's early times in the evolution of anxiety and complex behaviors. Human beings have been egalitarian hunter gatherers for 99% of our existence on this planet. We are simply not used to dealing with such complexity in our environment and social circles. Our cerebral "wet-ware" hasn't developed coping mechanisms as yet to deal with such a complex world. However, clearly it's only a matter of time before this happens. It's my firm belief that anxiety and stress have a small part to do with sex. I also believe that sex causes anxiety, not the other way round. Sexual jealousy and thought statements such as: "do I look ok for the opposite sex", "is my work interfering with my sex life", "will he be ok with me talking to this other guy", "is my relationship healthy"; play a large part as the root cause of many of our anxieties. Sex to relieve anxiety can merely be seen as a distraction from the root cause, not a cure. Additionally, the natural calculation and fantasy over a number of sexual taboos that are culturally determined play over conflict in our heads. Conflict with our sometimes natural tendency as a primate species to be monogamous, polygynous, homosexual and bisexual (noting that most homosexuals also exhibit anxiety symptoms (Jorden 1998)). The other causes of anxiety deal with day to day mundane complexities of living with a brain that is hardwired to find yams and water in a parched desert, but functions in an environment full of buttons, choices, money (a very new concept for our species) and everything else from the mundane to the not so mundane. I am also of the belief that the neurochemical basis of anxiety that most researchers are basing their opinions of these days (while keeping the pharmacutical companies fat and rich) is a proximate causation rather then an ultimate one. Therefore in taking psychotropic substances we are merely dulling down receptors that connect with certain feelings. The feelings are still there, we just loose our ability to associate with them. So then maybe anxiety is a predetermined possibility through our genes, played out through the environment we live in.

Ref: http://www.haworthpress.com/store/E-Text/View_EText.asp?a=4&fn=J082v35n02_03&i=2&s=J082&v=35

 

[m4dd0g]

Why would you want to remove it?

A disciplined mind can use it to motivate, create and expand mental/emotional horizons. Genetically its there for a purpose and removing it to create a mental 'Nirvana' would probably neuter the race and turn us all into a bunch of mushrooms

If its a severe chemical imbalance then thats a different story.

I'd rather embrace pain than be waiting to die

 

[endlesseulogy]

^^ Good point. I guess the answer to that question would be dependent on how much "complexity" effects you're life. But I think it would be beneficial to have the ability to 'switch' between states without any effort apart from thinking about it. For example. The separation of work from leisure. It would be a great thing to be able to drown out anxiety surrounding you're career when you go home at the end of the day, instead of ruminating about it. Excessive stress and anxiety in my opinion, has the tendency to break down family bonds, which, when broken would be a more expedient way of "neutering the race".

 

[m4dd0g]

Being able to switch it on/off at will would have advantages and disadvantages.

You would be able to think about things more objectively.
You would also weaken life's 'weight' - who cares? just switch it off

Its probably fine for the unwashed masses but it would destroy the output of our high achievers. They are usually tortured individuals and with an off switch available, they'd take it

 

[Rated E]

Great post endlesseulogy. You brought up some good points, in that sex may actually be a major cause of anxiety. Though that anxiety can still be preventative of success or even desire with and of sex.

Also the point about humans not being fully adapted to the complex world that we have created. I think it's fascinating to think that our species could become more and more adapt to the ever complex world that it inhabits.

Why would you want to remove it?

It was not about a want or preference to remove the capability. But rather musing as to whether the process of natural selection would move away from it rather than ever more towards it.

A disciplined mind can use it to motivate, create and expand mental/emotional horizons. Genetically its there for a purpose and removing it to create a mental 'Nirvana' would probably neuter the race and turn us all into a bunch of mushrooms

Sure. It's like endlesseulogy was saying. Perhaps the anxiety, depression, whatever, is a result of the species not being fully adapt to the complex society that we live in. Perhaps the ones with more complex thinking abilities that also have more "disciplined minds" will fare better in procreation and we will become more adept while maintaining ever increasing complexity of cognitive ability.

If its a severe chemical imbalance then thats a different story.

The idea that mental disorders such as anxiety or depression are caused by chemical imbalances is not really a fact. It is not known whether it is anxiety and depression that causes the imbalance or whether the imbalance causes the anxiety and depression.

 

[endlesseulogy]

^^ Infact if you want to go down the road of evolutionary speculation, i personally think that people more equipped with abilities to clear the mind will have better survival chances in a complex world. I also think now that the gender roles are becoming more transparent, individuals that have a greater capacity to discard social norms and rigidity placed on sex and sexual indentity will fare better at passing on their genes, as is the case for me; the expectations of women for what makes a good mate are no longer just symmetrical faces and the ability to provide resources. Because, as the world becomes complex, people's needs and desires will take on new forms.

But getting back to the point. As the world becomes more complex, those who are able to deal with complexity will be the winners, not those who aspire to it. That being said, those who are too complacent and with to withdraw from a complex world will also loose out. I think essentially it's about your ability to adapt

 

[m4dd0g]

Idealistically i agree.

But a guys ability to stick his dick in a girl and for her to get pregnant (and want to keep it) have almost nothing to do with either parents ability to cope successfully with the world

In my experience the majority of breeders are lost, confused and hide from the world behind their partners inane assurances

 

[Pop Popavich]

I have nothing productive to add this early in the morning, but needed to share this:

 

[Busty St Clare]

Science is not for pussies indeed.....

 

[vanth]

Heheh, hilarious Pop_Poppavich, This is what science was like before those pesky ethics committees were invented

 

[endlesseulogy]

A recent article on "Epigenetics". It's possible that environmental stress that happens during an individual's lifetime can be passed on through DNA and mRNA to future generations.

How your behaviour can change your children’s DNA
New research into inheritance shows we can alter family traits for better or for worse. Jonathan Leake reports

For Beatrix Zwart being young means having fun. She works hard, and out of hours she plays hard — including plenty of nights on the town with her friends.

“I lead a similar lifestyle to a lot of young professionals in Britain and I don’t intend to have any children until I’m well into my thirties,” said Zwart, a 25-year-old Belgian who lives in London.

“I’ve never really thought my lifestyle now could have any effect on my future children or grandchildren.”

Until recently that would also have been the opinion of most scientists. Genes, it was thought, were highly resilient. Even if people did wreck their own DNA through bad diet, smoking and getting fat, that damage was unlikely to be passed to future generations.

Now, however, those assumptions are being re-examined. At the heart of this revolution is a simple but controversial idea: that DNA can be modified or imprinted with the experiences of your parents and grandparents.

According to this new science, known as epigenetics, your ancestors’ diet, smoking habits, exposure to pollutants and levels of obesity could be affecting you today. In turn, your lifestyle could affect your children and grandchildren. For Zwart and millions of others choosing to delay parenthood this raises new moral questions. What effect, for example, will nights spent in wine bars have on their descendants? Will cigarettes smoked today compromise the health of grandchildren? If they become obese is that their right, or does it impose a burden of ill-health on generations yet unborn?

Some of the answers may be emerging. There is, for example, evidence that the recent surge in diseases such as diabetes, obesity and heart disease is partly linked to the lifestyles of past generations.

Last week academics at Baylor College of Medicine in Houston, Texas, published research showing that overweight mothers produce offspring who become even heavier, resulting in the spread of obesity across the generations. “There is a worldwide obesity epidemic,” said Robert Waterland, a professor of paediatrics who led the study. “Why is everyone getting heavier and heavier? One hypothesis is that maternal obesity before and during pregnancy causes epigenetic changes in the ways genes are expressed.”

Waterland’s research was done in mice for ethical reasons but population studies have suggested similar effects in humans.

Marcus Pembrey of the Institute of Child Health at University College London identified 166 fathers who admitted smoking before they were aged 11, and whose sons had a sharply elevated risk of obesity. The implication was that smoking had altered the way their genes worked without actually changing the genes.

In another study Pembrey and colleagues analysed records of an isolated Swedish community to find that men whose grandfathers had experienced childhood food shortages tended to live longer. They too appeared to have inherited a change in the way their DNA worked — this time a beneficial one.

Researchers had long suspected that DNA may not be the only means of inheritance. They knew that diseases

such as cancer, heart disease and diabetes ran in families, but in complex patterns that seemed to defy traditional genetics. What they lacked were the instruments to peer into cells and see what was happening.

What’s more, other scientists saw such ideas as heretical, amounting to an attack on the evolutionary theories of Charles Darwin and the laws of genetic inheritance outlined by Gregor Mendel, two of the cornerstones of modern biology.

The next year will witness a rash of celebrations for the bicentennial of Darwin’s birth. It will also see publication of a number of academic papers on novel forms of inheritance.

Steve Jones, professor of genetics at University College London, said: “The evidence is increasingly that environmental factors like diet or stress can affect organisms in ways that are transmitted to offspring without any changes to DNA.”

Such apparent conflicts can be resolved but only by finding out what is happening at the level of DNA molecules — the basic building blocks of life — and scientists have never had that power until now.

“The technologies for epigenetics arose from the human genome project and have only become widely available within the last few years,” said Stephan Beck, professor of medical genomics at the Cancer Institute, University College London. “That is what makes it so exciting.”

A key finding is that although DNA molecules control almost everything that happens in a cell, each molecule contains far more information than any single cell needs.

A liver cell, for example, has no need for the genes that govern sperm production, while a brain cell that started generating, say, hair or nails could be positively dangerous.

This means that in every cell some genes are turned on but many more are “trussed up” and neutralised by a host of smaller molecules. The change, then, is not to the DNA itself but to the “switches” that turn the genes on or off.

The system that oversees this process, the epigenome, is meant to be flexible enough for such genes to be brought in and out of play as needed. Sometimes, however, it goes wrong.

For example, a research group from Toronto’s Centre for Addiction and Mental Health looked for differences in post-mortem tissue taken from the brains of 35 men suffering from schizophrenia, a disease that runs in families but without any clear pattern. They found epigenetic changes affecting 40 or so key genes involved in brain function.

“The brain is particularly susceptible to epigenetic changes, especially during development,” said Dr Jonathan Mill, a lecturer in psychiatric epigenetics at the Institute of Psychiatry who was involved with the research. “That is why pre- natal exposure to alcohol or other toxins may have such a strong effect.”

For humans perhaps the most important finding of epigenetics is that we are not owners of our genes but their guardian. If we drink heavily, take drugs, get fat or wait too long to reproduce, then epigenetics might start tying up some of the wrong genes and loosening the bonds on others. Sometimes those changes will affect sperm and egg cells.

One of the clearest pieces of evidence for such changes emerged from the work of Avi Reichenberg, also of the Institute of Psychiatry. He found children born to fathers aged 40-plus were almost six times more likely to have autism than those born to fathers under 30 and that the effect appeared to be epigenetic.

In a society where people have children later in life, such effects have huge medical and social implications, suggesting that people putting off parenthood should be looking after their DNA.

Zwart is on the right track: recently she started a twice-a-week exercise regime, something for which any future children and grandchildren may well have cause to thank her.

Additional reporting: Jasmine Gardner

Inherited theories

Charles Darwin, above, outlined his theory of evolution by random mutation at a lecture 150 years ago this month. The Origin of Species was published in 1859 and rapidly won acceptance.

Among the ideas it displaced were those of Jean-Baptiste Lamarck, who thought characteristics acquired during an organism’s lifetime could be passed to its offspring.

Neither man had any idea of how inheritance actually worked. DNA and its role were unknown and Gregor Mendel, the father of modern genetics, did not publish his famous findings on inheritance in pea plants until 1866. Even then he was largely ignored for nearly 40 years.

Epigenetics does not contradict Darwin or Mendel, but it does suggest there was some truth in Lamarck’s ideas.

 

[lostpunk5545]

Well, I'll be fucked if I ever see this play out in practice, but then again, I do live in an area mostly populated by bogans:

Nerds rejoice: Braininess boosts likelihood of sex

* 15:57 03 October 2008
* NewScientist.com news service
* Ewen Callaway



Lonely men ought to flaunt their copies of New Scientist. Women looking for both one-night stands and long-term relationships go for geniuses over dumb jocks, according to a new study of hundreds of university students.

"Women want the best of both worlds. Not only a physically attractive man, but somebody in the long term who can provide for them," says Mark Prokosch, an evolutionary psychologist at Elon University in North Carolina, who led the study.

To many women, a smart man will appeal because he is likely to be clever enough to keep his family afloat. But he may also pass on "good" genes to his children, say Prokosch and his colleagues at the University of California, Davis.

Rather than ask women to rate qualities they seek in men, as other studies had done, Prokosch's team asked 15 college men to perform a series of tasks on camera.

The volunteers read news reports, explained why they would be a good date, and what would be the ramifications of the discovery of life on Mars. They also threw and caught a Frisbee to parade their physical appeal. Each potential suitor also took a quantitative test of verbal intelligence.

Smart is sexy

More than 200 women watched a series of these videos before rating each man's intelligence, attractiveness, creativity and appeal for a short-term or long-term relationship.

While the difference between short- and long-term mates may amount to a boozy decision students face each weekend, it has some evolutionary significance, Prokosch says. In potential husbands, women look for signs that a man might be a good provider and father. In one-night stands, women are on the prowl for little more than good genes, not to mention a good time.

Women proved to be decent judges of intelligence, with their scores generally matching each man's intelligence test results.

As for picking a bed-mate, the men's actual smartness proved a reliable indicator of their appeal for both brief hook-ups and serious relationships – which came as something of a surprise. Other studies have suggested that, for women anticipating short-term relationships, a man's braininess isn't foremost in their minds.

The disparate results may be due to women's lack of awareness that intelligence also affects the attractiveness of candidates for quick flings – how intelligent women perceived a man to be influenced his desirability as a long-term mate much more than his appeal for a one-night stand.

Bright and beautiful

Martie Haselton, an evolutionary psychologist at the University of California in Los Angeles, also notes that although women were good judges of intelligence, they weren't perfect. In many cases, women rated good hook-ups as dunces, when their intelligence scores indicated otherwise.

"There could be aspects of intelligence that we pick up on when we interact with a person and that affect our assessment of them, even if we wouldn't label it as intelligence," she says.

But some things never change. Looks were still a much more powerful predictor of sex appeal than brains. "Women are still going for the hunk," Prokosch says. "If you had an option to pick from five different people, you would pick the most attractive one."

So in a perfect world, women want a Nobel prize winner with movie-star looks. Creativity also proved to be a sought-after trait, and Prokosch's team is currently working on an objective measure of creativity, similar to the intelligence test they used.

However, in a world of limited resources, not every woman gets what she wants, and some are bound to fall for ugly, unintelligent and uncreative men. "There's always other people out there that find everything attractive," Prokosch says.

 

[ostrich]

stop the presses! a bunch of university students, relatively intelligent people, would like to get with other relatively intelligent people?!

a new study should show that bogans also like other bogans.

 

[vanth]

Intelligence is very important to me when considering a mate. She said creepily.

 

[belarki]

Intelligence is very important to me when considering a mate.

Me too; the more intelligent she is the less likely she is to get with me