Wikipedia:Reference desk/Archives/Science/2013 August 29

= August 29 =

Can't remember the name of a medical condition
An elderly acquaintance was recently diagnosed with a medical condition, and I can't remember its name. All I know is that it's causing severe pain in her back, and the condition's name begins with "arach", but the condition apparently doesn't have anything to do with spiders. Any clue what I could be thinking of? Nyttend (talk) 01:36, 29 August 2013 (UTC)


 * It isn't Sciatica is it? -- Jayron  32  01:38, 29 August 2013 (UTC)
 * Arachnoiditis Hot Stop talk-contribs 01:46, 29 August 2013 (UTC)


 * The name "arachnoiditis" sounds right, and the description in the article sounds a lot like the symptoms that she's experiencing. Thanks!  Nyttend (talk) 02:15, 29 August 2013 (UTC)


 * Helpful advice: next time try typing in the words you know first for sure, "back pain", to google, and then start typing a...r...a...c...h... and it will fill in the answer for you. μηδείς (talk) 02:53, 29 August 2013 (UTC)


 * You just gave away my secret. Hot Stop talk-contribs 03:50, 29 August 2013 (UTC)


 * Didn't even think of that...Nyttend (talk) 03:54, 29 August 2013 (UTC)


 * That's why I get paid so much. μηδείς (talk) 05:34, 29 August 2013 (UTC)


 * And you are worth every cent we pay you, maybe even twice as much. StuRat (talk) 06:12, 29 August 2013 (UTC)


 * I can never seem to remember the name for the medical condition, aphasia. :-) StuRat (talk) 06:12, 29 August 2013 (UTC)
 * I'm sure I know it, but I usually just can't quite conjure up the name for presque vu. DMacks (talk) 06:17, 29 August 2013 (UTC)
 * Just read schizophrenia – great article, made me think twice. - ¡Ouch! (hurt me / more pain) 08:02, 29 August 2013 (UTC)
 * What are you telling us about our question, Ouch? Nyttend (talk)  Nyttend (talk) 11:11, 29 August 2013 (UTC)


 * The condition's connection with spiders is only in the name, as "arachnoid" means "cobweb-like". ←Baseball Bugs What's up, Doc? carrots→ 11:40, 29 August 2013 (UTC)


 * The reference is to the arachnoid mater, a thin and spiderweb-like layer of tissue that encloses the brain and spinal cord, between the dura mater and pia mater. Looie496 (talk) 22:09, 29 August 2013 (UTC)

Elysium – "open to space" space station?
In the recent movie “Elysium”, Elysium is a rotating space station orbiting Earth, designed as a luxurious gated suburb for the world’s wealthiest. These types of space stations mimic gravity by rotating giant rings in which people can reside (as made famous in the movie 2001). It appears that they could indeed work very much as depicted in that film. But in the movie Elysium, the station has a feature I have never seen depicted before, and I very much doubt could work. The rings of the space station are al fresco, that is, they have no covering at all. The idea is that the rotational velocity that provides the “gravity”, also keeps the air from expanding. (The depth of Elysium’s atmosphere appears to be no more than half a mile or so, at the most.) I suppose the designers would have considered:

"'Earth is a rotating space station with gravity, and no hard covering between it and the vacuum of space, and Elysium is a rotating space station which mimics gravity, so why should it have a hard cover either?'"

link

I wrote in an IMDB msg board that air pressure would immediately make the air boil away on Elysium, and that on Earth it takes miles of atmosphere to get the pressure we have at ground level. This blooper is not recognised as such in the “blooper list” of the movie, and I can only think that most people are not aware of how wrong it is. Unless, of course it is I who am wrong....Could that be possible? Myles325a (talk) 07:12, 29 August 2013 (UTC)


 * Air pressure on Earth is about 100,000 Pa, and that would be needed on the space station as well. One cubic meter of air weighs in at just above 1kg, so 500m of air would weigh 500kg per square, which is 5000N at 1.0g. So we have 5000 Pa, not 100,000 Pa. The factor of twenty means that the air would be gone quite fast, even by that ballpark estimate. - ¡Ouch! (hurt me / more pain) 07:50, 29 August 2013 (UTC)

OP myles325a back live. Thanks One.Ouch, but could you and succeeding posters spell out jargon properly? I don't know what a PA is; I gather it is an initialism. Anyway, I'm getting the drift, but a more accessible explanation would be appreciated. Myles325a (talk) 08:22, 29 August 2013 (UTC)
 * I presume Pa = Pascal (unit). I haven't seen the film (or even heard of it until now) but surely another problem is that it would be impossible to maintain a survivable temperature in the "open air". AndrewWTaylor (talk) 08:31, 29 August 2013 (UTC)
 * For Niven's Ringworld, the open architecture is plausible (even if the ringworld itself is not ;-). But then the "walls" of the Ringworld are 1000 miles high, not half a mile. At 1000 miles, the atmosphere is essentially all below you. --Stephan Schulz (talk) 09:12, 29 August 2013 (UTC)
 * Also see Orbitals, Halos and Bishop Rings. But these fictional/hypothetical structures all appear to be much larger than the Elysium space station, and depend on some form of unobtainium (such as Niven's scrith) to keep them in one piece. Gandalf61 (talk) 09:33, 29 August 2013 (UTC)
 * The Halos in your link make extensive use of hyper-dimensional architecture, metamaterials, nanomaterials, and exotic matter (to manipulate space-time), it does not rely on simple Newtonian mechanics to function. Plasmic Physics (talk) 12:26, 29 August 2013 (UTC)
 * Yes, that's the sort of thing I loosely filed under "unobtanium". Gandalf61 (talk) 16:25, 29 August 2013 (UTC)


 * In a thread elsewhere on this page, I linked to a review of the film by Gary Westfahl, in which he touches on this topic. Deor (talk) 13:02, 29 August 2013 (UTC)


 * The basic issue is that the scale height of an atmosphere doesn't permit this. Any atmosphere of Earthlike temperature and composition under Earthlike gravity is going to have a scale height of about 7.5 kilometers, which means that the pressure at the top of a 500-meter wall (1/15 of a scale height) is going to be around 95% of the surface pressure.  If you want a 500-meter wall to retain an atmosphere, you'll need to reduce the scale height, either by using a denser gas (sulfur hexafluoride has a scale height of 1.5 km, still too much), or by increasing gravity (a surface gravity 70 times that of Earth's will drop the scale height to 107 meters, putting the top of the wall above 99% of the atmosphere).  Reducing the temperature isn't an option, because by the time you get it low enough (3.5 kelvin), not even helium is a gas. --Carnildo (talk) 23:57, 29 August 2013 (UTC)


 * I think Carnildo has got it right. Summarising a few points, which might not be obvious to the OP (or which could do with a bit of clarification at any rate), we can say that the earth's gravity is due to its mass, but that on Elysium is due to rotation. If it is due to an artificial gravity machine (I don't think the film actually explained this), then all bets are off. Supposing it is rotation, the atmosphere is only kept in place as long as it lies beneath the walls. If it spills over at all, its angular momentum will carry it off into space. So unless the atmosphere at the top is allowed to boil off, whilst keeping the atmosphere below at some constant density, it will all float upwards, then away. But as Carnildo's link shows, the atmospheric density declines as a function of temperature, density and gravity, and none of these are arbitrary, if we are to create livable conditions. IBE (talk) 08:44, 30 August 2013 (UTC)

How was the moon created?
how was it made — Preceding unsigned comment added by 196.29.167.50 (talk) 08:47, 29 August 2013 (UTC)
 * See Moon and the articles linked from there. Rojomoke (talk) 08:55, 29 August 2013 (UTC)


 * A 2013 hypothesis suggests that the Moon formed from debris ejected from a cataclysmic thermonuclear detonation of the core of proto-Earth. Plasmic Physics (talk) 12:06, 29 August 2013 (UTC)
 * If our own articles aren't enough for you, could you supply a reference for your alternative? Rojomoke (talk) 12:13, 29 August 2013 (UTC)
 * . Plasmic Physics (talk) 12:17, 29 August 2013 (UTC)


 * What would such a detonation look like, would the Earth vapourise, or will gaint asteroids be thrown out, or something in between? Plasmic Physics (talk) 01:40, 30 August 2013 (UTC)

"Despite what the revisionist historians tell you, there is no mention of the 'moon' anywhere in literature or historical documents -- anywhere -- before 1950. That is when it was initially launched." 178.48.114.143 (talk) 23:45, 29 August 2013 (UTC)
 * "O, swear not by the moon, the fickle moon, the inconstant moon, that monthly changes in her circle orb, Lest that thy love prove likewise variable" SteveBaker (talk) 17:56, 30 August 2013 (UTC)

Antoher black hole question
Excuse me, I have another question about black holes: if they increase their mass by absorbing other stars even to us external observers, the fact about an object that stops on the event horizon is only an optical illusion (inother the gravitational time dilatation is valid even if object is on free fall?)? Thanks for your patience.95.234.63.70 (talk) 10:43, 29 August 2013 (UTC)
 * No, it is not an illusion, rather it is physical reality imposed by the principle of relativity: the notion that there is no universal frame of reference. In simplest terms, how you observe what happens at the event horizon depends on where you do the observing.  To the person observing from the outside, the object falling into the black hole stops at the event horizon, while to that object itself, nothing special happens.  They keep falling, without any special event that would even tell them they crossed it.  The difference in observations between te two situation is nothing like an optical illusion.  It's just that different observers in different frames of reference observe the event differently.  That's what relativity means. -- Jayron  32  11:14, 29 August 2013 (UTC)


 * Both the external and internal points of view are real, hence the name relativity. Dauto (talk) 12:28, 29 August 2013 (UTC)


 * There is a complication here; unlike in Special Relativity there is no unambiguous way an observer can say when an event happened at a different location. This is not a problem in special relativity. So, the OP does have a point, you can't simply say that when the light signals arrive, that's when the event happens in your frame as that's not true in Special Relativity.


 * You can e.g. consider sending the infalling observer a message via light signals. What you find is that a message sent later than a certain time will never be received by the infalling observer. Count Iblis (talk) 13:10, 29 August 2013 (UTC)

Yes, but the problem is: we (external observer) see black holes absorbing other stars and so increasing their mass, we don,t see star stopping at horizon's surface (it's probably that the object stop its time but we see it equally falling into black hole). 95.234.63.70 (talk) 13:29, 29 August 2013 (UTC)
 * We would never see a star cross the event horizon, in practice we simply measure the mass of a black hole by considering how fast stars orbit it, so everything that is just outside the event horizon will then also be attributed to the mass of the black hole. Count Iblis (talk) 13:40, 29 August 2013 (UTC)


 * When we say that "the object stops at the event horizon" - we mean that each individual subatomic particle stops at the event horizon. So don't imagine a planet, buried forever, half inside and half outside of a black sphere.  A better mental image is that as the planet (star, rock, spaceship) heads towards the black hole, tidal forces rip it apart - and eventually, rip even the atoms apart.  From an outside observer's perspective, time for each individual quark (or whatever) slows right down and stops at the precise instant it hits the event horizon.  The event horizon itself grows with each new addition of mass - so those objects do cross the event horizon and vanish - even from our perspective.  But the idea that it's black at all is a bit misleading - these objects that are falling into the black hole are emitting immense amounts of radiation - some of which is visible from far away and is further smashing up the incoming stuff.   The event horizon itself must have a fantastically small layer of sub-atomic mush that (to us) seems to be going slower and slower.  But the actual appearance is even more confusing than that because gravitational red-shift is shifting the frequencies of light (and radio and X-rays, etc) so far off the chart that they'll be indetectable anyway.  Roll in quantum effects and black-hole evaporation, hawking radiation...it's not a simple picture to imagine.


 * SteveBaker (talk) 13:41, 29 August 2013 (UTC)

This could be certainly possible for stellar black hole, but for very supermassive black holes with irrilevant tidal force and low surface gravity, a compact object wouldn't ripped apart. Inother, on a freefall is still valid the gravitational time dilatation? It isn't valid only if the object oppose resistance to gravity?80.116.228.11 (talk) 14:14, 29 August 2013 (UTC)


 * Gravitational time dilation still aplies for free falling objects plus there will also be some Doppler red shifting due to the motion of the object. The star certainly never reaches the horizon due to the (infinite) gravitational time dilation. Not only that, if quantum effects are included (as shown by Leonard Susskind), the individual particle orbitals enlarge until they wrap around the B-hole covering the whole surface. Off course, from the point of view of the falling object, none of that happens Dauto (talk) 15:21, 29 August 2013 (UTC)

Ageing
Is there an age where every organ of the body is at peak performance and nothing is growing or declining, since apparently growth and decline happens at different ages for different parts of the body？Clover345 (talk) 12:29, 29 August 2013 (UTC)


 * No. Life operates at the edge of chaos, and stasis is death (at least, according to Stuart Kauffman). See section 4.5.1 here, which summarizes some of Kauffman's work on gene expression in complex networks. Gene expression is basically what controls developmental biology, and also senescence. I'd also recommend "At Home in the Universe" , but you'd have to go to a library or buy it. SemanticMantis (talk) 14:51, 29 August 2013 (UTC)


 * Most aspects of physical and mental performance peak in the age range 20-25 for men, a bit younger for women, if I've grasped the data correctly. However, maximum strength for weightlifters peaks later, in the 30s, I believe. Looie496 (talk) 16:37, 29 August 2013 (UTC)


 * Also, memory power, ability to absorb more education and raw thinking speed are all places where younger people do well - but cunning, knowledge and "wisdom" are attributes associated with older people. On that basis alone, I'd say that there is no particular age at which you can say that the brain is at it's peak. SteveBaker (talk) 17:54, 30 August 2013 (UTC)

BMI
Is BMI an accurate measure of body faT? For instance would a body builder have a low BMI or a High one because he has very little fat but a lot of muscle?--86.181.30.8 (talk) 14:09, 29 August 2013 (UTC)


 * No it isn't very accurate and recent reseach points out to problems with using the MBI. The BMI is, however, a good general indicator, but it can be misleading. A body builder can have a high BMI while having an extremly low body fat percentage. People of Asian origin can have a low BMI while having a lot of fat, putting them at high risk of developing heart disease and diabetes. Count Iblis (talk) 14:59, 29 August 2013 (UTC)


 * (ec) No, it's certainly not accurate. Our Body mass index article has a section Body_mass_index which you should probably read.  It was always intended as a statistical means to estimate body fat over a large number of people - using it for an individual is problematic and has huge possibilities of error.  However, it's extremely easy to measure - and it can provide a useful (if highly approximate) answer for some applications. SteveBaker (talk) 15:03, 29 August 2013 (UTC)

FAT
Does eating fat, on its own, make one fat?--86.181.30.8 (talk) 14:16, 29 August 2013 (UTC)


 * No, and not even a high total calory intake will on its own make one fat. Controlled experiments have consistently failed to demonstrate a link between diet and obesity. That doesn't mean that such a link over a long period does exist, just that it isn't as simple as eating too much for a while and putting on weight as a result. Count Iblis (talk) 15:02, 29 August 2013 (UTC)


 * I agree it's not as simple as that...but the ways in which it's not simple need to be explained very clearly before making such an extreme claim. You need to be VERY careful about how you phrase that - it's misleading in the extreme to say that your diet doesn't affect whether you're obese or not - and many, MANY sources would disagree with that.  I think Count Iblis needs to provide us with some very good references for this rather extreme claim - and explain in considerably more detail what is meant by it.  His preceding statement is horribly misleading! SteveBaker (talk) 15:11, 29 August 2013 (UTC)


 * No, if you kept your exercise schedule the same and instead of eating (say) 2,000 calories of carbohydrates each day (sugars, starches, etc) - you switched to eating 2,000 calories of fat instead - then you would be unlikely to change weight significantly as a result. Other health indicators such as cholesterol might go badly wrong - but the calorie intake is the same, it won't make you fatter.  However, if you're eating a good diet and then add 2,000 calories of fat to your diet each day - then you'll put on weight rather rapidly! SteveBaker (talk) 15:11, 29 August 2013 (UTC)


 * Forgive me for not trusting the comments above, I had to look it up.
 * Here's a ref that is relevant to the question. The percentage of energy from dietary fat is widely believed to be an important determinant of body fat, and several mechanisms have been proposed to account for such a relation. Comparisons of both diets and the prevalence of obesity between affluent and poor countries have been used to support a causal association, but these contrasts are seriously confounded by differences in physical activity and food availability. Within areas of similar economic development, regional intake of fat and prevalence of obesity have not been positively correlated. ... ... Moreover, within the United States, a substantial decline in the percentage of energy from fat consumed during the past two decades has corresponded with a massive increase in obesity. Diets high in fat do not appear to be the primary cause of the high prevalence of excess body fat in our society, and reductions in fat will not be a solution.
 * Emphasis added by me. From here, an article from The American Journal of Clinical nutrition, 1998. SemanticMantis (talk) 15:16, 29 August 2013 (UTC)
 * Yes - but that's not what Count Iblis said. He said (in essence) that calorie intake isn't the culprit and that diet doesn't matter - and without some pretty strong evidence, I have to call "bullshit" on that claim.  The reason that decreasing fat intake doesn't reduce obesity is that people eat more carbohydrates (sugar, starch) to make up for it.  Total calorie intake is the key - and it doesn't matter all that much where the calories come from. SteveBaker (talk) 17:40, 29 August 2013 (UTC)
 * Despite my phrasing, I wasn't really responding to you or Iblis, just providing a ref that I thought addressed the OP's question. I've stricken part of my post to make my intent more clear. SemanticMantis (talk) 17:55, 29 August 2013 (UTC)


 * See also Mediterranean diet, which is rather high in fat, and recently attracted lots of attention as a rather healthy diet (see refs in article). SemanticMantis (talk) 15:18, 29 August 2013 (UTC)


 * I don't know what you have in mind when you ask the question. If you are asking whether we accumulate the fat that we eat as fat in our body, then the answer is definitely no. Out bodies produce their own fat to store energy. But the fat that we eat has lots of calories, which make us fat. OsmanRF34 (talk) 17:28, 29 August 2013 (UTC)
 * The core determinant of weight is calories eaten vs. calories burned. If you eat a (say) 2000 calorie diet, and maintain the same activity schedule, the exact composition of the diet is of decidedly secondary consideration. But some diets are easier to maintain than others, and some (different ones, of course ;-) diets make it easier to exercise well. If you manage to eat a reasonable amount of your calories as fat without overeating in total, that's generally fine. --Stephan Schulz (talk) 17:36, 29 August 2013 (UTC)
 * Indeed, and a reasonable rule-of-thumb is that: weightGainedInPounds = (caloriesEaten - caloriesBurned)/3500
 * All diets that actually work have to play with how many calories your eat, or how many you burn, or some combination of the two. Mediterranean diets replace carbohydrates with fat - and hope that you'll be fooled into eating less calories because of it.  But if you eat too much fat you'll put on weight despite not eating a single unit of carbohydrate.  SteveBaker (talk) 17:52, 29 August 2013 (UTC)
 * Of course, one of the factors in overeating is the desire to eat itself. Different foods have a different affect on the sense of satiation; and foods that make you feel fuller with less calories are generally considered preferrable, if only because a person who is satiated (full) will eat less calories if their diet contains more foods that "fill you up" while providing less calories.  Without going into exhaustive detail as to which foods tend to be more satiating; that has to be a factor in considering a healthy diet, from an "obesity-avoidance" perspective.  People who are less hungry eat less food, so foods that fill you up and provide less calories in doing so are, on the balance, better for you.  -- Jayron  32  18:11, 29 August 2013 (UTC)

I think the OP's question has been answered, but there is the question about what I wrote about total calory intake. What I'm saying is that it is not a universially valid statement to say that a big increase in calory intake will lead to a big weight gain. That doesn't mean that it will lead to weight gain in some people (paticularly if you are already obese, your weight will be more sensitive to the calory intake). But controlled experiments on people who are deliberately given way more to eat than they normally do (e.g. 5000 Kcal/day instead of 2500 Kcal/day) have debunked the simple calories in - calories out = weight gain model, see e.g. this documentary:

"In 1967, a medical researcher, Ethan Sims, carried out an experiment at Vermont state prison in the US. He recruited inmates to eat as much as they could to gain 25% of their body weight, in return for early release from prison.

Some of the volunteers could not reach the target however hard they tried, even though they were eating 10,000 calories a day. Sims's conclusion was that for some, obesity is nearly impossible.

It was with this in mind that 10 slim volunteers - who were not dieters - convened in more hospitable circumstances, for a recent experiment devised by the BBC's Horizon documentary. The 10 spent four weeks gorging on as much pizza, chips, ice cream and chocolate as they could, while doing no exercise, and severely limiting the amount they walked."

Count Iblis (talk) 18:37, 29 August 2013 (UTC)


 * The calories in vs. calories out model has not been debunked. More likely we just have a tendency to give wrong estimates of both variables. Calories in ones mouth may be consumed by gut flora or excreted intact. Calories out is impacted by basal metabolic rate, which may not be as constant as some would believe. Someguy1221 (talk) 21:01, 29 August 2013 (UTC)


 * Now what you said makes sense. Although I wouldn't dismiss Steve Baker's formula. In thermodynamic terms, it's true that 1 pound of fat equals 3600 kcal. But it appears that not all the calories that you intake can be stored. I would just expand the formula to include things about current weight and amount of extra kcal (the first 3600 extra kcal might give you an extra pound, but the same can't be true for the following groups of 3600 kcal). OsmanRF34 (talk) 18:46, 29 August 2013 (UTC)
 * Yes, the body will increase its metabolic rate to compensate for the increased calory intake. Without such a mechanism, eating slightly less would lead you to eventually starve to death. If you eat 2500 Kcal per day and you have a stable weight, then you won't starve to death if you start to eat 2400 Kcal per day and at the same time start to exercise a lot more. What happens is that your body will eventually start to burn 2400 Kcal per day. This is possible because the amount of calories used during heavy exercise isn't that much, the body can easily compensate for that by adjusting the metabolic rate.
 * Exercise is still important for maintaining a healthy weight, not because you burn a significant amount of calories, but because it enables this feedback mechanism to operate better. Count Iblis (talk) 20:28, 29 August 2013 (UTC)


 * But it's essential to note that the finding on calorie intake vs. calorie use only works in one direction. It violates no scientific principles for the body to eliminate excess calories without exercise, whether by increasing metabolic rate or by simply passing the excess through digestive tract without uptake, and simply allowing the gut flora to consume those calories. But if you start consuming fewer calories than your body intakes (or start burning more), you must be burning fat or something else to compensate. Someguy1221 (talk) 20:58, 29 August 2013 (UTC)


 * What Iblis has found is that sometimes, some people, under some conditions, can eat a lot of calories and not gain weight. Extrapolating the results of highly limited experiments is a suspicious way of making sweeping generalizations about all of humanity, doubly so when one merely cherry picks those specific experiments that happen to confirm the conclusion one had reached prior to searching for evidence in the first place.  -- Jayron  32  22:43, 29 August 2013 (UTC)
 * Jack Sprat, for example. ←Baseball Bugs What's up, Doc? carrots→ 23:30, 29 August 2013 (UTC)

dog intelligence ranking
This is just a personal issue for me but Australian shepherds are listed as average intelligence while they and Border Collie rule the agility world, not the domain of dumb dogs. And to be truthful, most people pick agility dogs so they will be easy to train. Something is wrong with Coren's list. Maybe the new book about Chaser, the Border Collie, will be better. — Preceding unsigned comment added by Aikenite (talk • contribs) 22:52, 29 August 2013 (UTC)
 * Interesting, but this page is for asking questions, not to be used as a forum for expressing opinions. Looie496 (talk) 00:14, 30 August 2013 (UTC)
 * The OP has opened an interesting topic. Intelligence in dogs is an ill-defined thing. Dog intelligence and The Intelligence of Dogs seem to be our main articles, with the latter being about Coren's book, referred to in the OP's question. Some think that being reliably obedient and easy to train to perform tricks is a sign of intelligence, but we would probably ask serious questions about a human with such traits. Others suggest that the sneaky, disobedient dogs, like my beagle who stole half my lunch off the kitchen bench I didn't think he could reach when my back was turned, are smarter. Until we can agree on that, we won't agree on which are the intelligent breeds. HiLo48 (talk) 06:18, 30 August 2013 (UTC)


 * I agree - I had a relatively disobedient lab mix ("Sarah") and a very well-behaved, trainable god-knows-what mix ("Sam"). Sarah learned (by herself) that scratching at the back door would get one of us humans to come to the door and let her in.  No amount of training would get her to stop scratching the paint off of the door...and the only way to save the door was to let her in...Argh!  Then, one day while working in the back yard, I saw Sam standing patiently looking at the back door in the hope that by sheer force of will, it might maybe open...Sarah rushed all the way across the yard, scraped frantically at the back door - then ran away and went back to what she was doing as my wife opened it.  Seems pretty obvious that she did that to let Sam in - knowing that he wasn't smart enough to do it for himself!  When I mentioned this to my wife, she said that she'd seen that happen several times before.  So, on the basis of that small measure, I'd definitely argue that "intelligence" and "trainability" were not only different - but possibly complete opposites.


 * That said, Border Collie's are very trainable - and they seem pretty intelligent too...but it's hard to know for sure.


 * Clearly, we don't have a good definition of "intelligence" - even in humans where we could measure it if only we knew what it was. (It's widely recognized that IQ tests don't measure what most people think of as intelligence).  Doing that in dogs would be just about impossible.  So I don't think there is a good answer to this.  HOWEVER: It clearly is possible to measure such attibutes as "trainability" and "obedience" with simple statistical measures. SteveBaker (talk) 15:20, 30 August 2013 (UTC)


 * I have dreaded what the dog genome project would uncover about the basis of instilling trainability and obedience. But I haven't heard much out of it since .  (Selective sweeps from the farm-fox experiment are also potentially informative; I see here they were doing basic mapping with backcrosses.)  I'm thinking "quiet ... too quiet". Wnt (talk) 15:26, 31 August 2013 (UTC)