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Mammals' large brains evolved for smell - Comments

liq's Avatar Comment 1 by liq

Smells like this could be an interesting read.

Sun, 22 May 2011 22:35:58 UTC | #629670

ai1888's Avatar Comment 2 by ai1888

I see what you did there

Comment 1 by liq :

Smells like this could be an interesting read.

Sun, 22 May 2011 22:40:12 UTC | #629673

liq's Avatar Comment 3 by liq

Seems I can sniff out a good article because it was interesting. Although I wish the BBC would do more than 3 line paragraphs.

Sun, 22 May 2011 22:47:50 UTC | #629677

Sara12's Avatar Comment 4 by Sara12

Comment 3 by liq :

Although I wish the BBC would do more than 3 line paragraphs.

Probably a style preference holdover from print. Something to do with not having too many lines per column inch because it's too hard to read. I worked for a couple of small weeklies here in the US (one of them was college) and we never had more than 2-3 sentences per paragraph either.

I read about smell and brain size a few days ago in a Reuters article. I would have sent it in but the last time I tried to send in an article it didn't get posted :( It's always been interesting to me how even the slightest smell can trigger memory. I wonder if that is related to the increase in brain size as well? It seems it must be. Remembering mates, remembering offspring, remembering good food or bad locations.

Mon, 23 May 2011 02:53:30 UTC | #629707

Alan Canon's Avatar Comment 5 by Alan Canon

I wonder if it's formatted like that so that it makes for easier reading as radio copy.

Mon, 23 May 2011 06:45:49 UTC | #629724

Anvil's Avatar Comment 6 by Anvil

Damn. Thought this was something new about hominid encephalisation?

Still, interesting use of CT, but can't imagine why they'd be "surprised to learn that smell was so important in mammal evolution"? Small, nocturnal, predator, close to the ground?

What senses would you imagine would be prone to selection in that environment?

Would love to have a window on what pumped up our own brains?

Anvil.

Mon, 23 May 2011 08:41:16 UTC | #629758

snail-12's Avatar Comment 7 by snail-12

I like the hypothesis in Susan Blackmore's book meme machine. That human brain expansion was driven by the benifits of imitation.(of course it doesn't mean its true though)

Comment 6 by Anvil :

Would love to have a window on what pumped up our own brains?

Anvil.

Mon, 23 May 2011 11:00:35 UTC | #629798

Anvil's Avatar Comment 8 by Anvil

Comment 7 by snail-12

I like the hypothesis in Susan Blackmore's book meme machine. That human brain expansion was driven by the benifits of imitation.(of course it doesn't mean its true though)

Yes, memetic drive. Keep meaning to read her book. (I've managed to say that for over a decade, now, - though I'm presuming to know where she's coming from after The Selfish Gene?)

Patently ideas as replicators that confer a survival advantage could form a co-evolutionary feedback loop. I can just about imagine this feedback loop taking a rapidly enlarging large brain into a (is it Pinkers?) cognitive niche - that once entered into conferred the ultimate advantage of allowing the species to step out of the evolutionary game.

But what caused our ability to take an opposable thumb and forefinger and flick away the almighty Red Queen, and when did it happen?

Nocturnal to diurnal? Posture? Stereoscopic/colour vision? Diet? Climatic upheaval? Isolation? Rudimentary tools?

Probably all - and more - but why our species and not others? Great questions that I hope will one day be answered.

Obviously the OP is dealing with a period long before this, and yes mammals as a general rule have large brains in relation to body-mass, (though I would have thought it obvious that brain region associated with smell is evolutionarily ancient?) but this doesn't explain the relatively massive brain that we have, does it?

I can't remember where I read it but had we the average mammalian brain/body ratio we would be so large as to be unable to walk - heh, I don't know if this is true but the imagery is sufficient to draw the distinction, I'm sure.

Still, interesting article - but a million miles and 60 million years away from what made our brains so huge. Would love to see some new stuff on this.

Anvil.

Mon, 23 May 2011 13:15:36 UTC | #629843

Schrodinger's Cat's Avatar Comment 9 by Schrodinger's Cat

Comment 6 by Anvil

hominid encephalisation

There must surely be an enormous area of the brain devoted exclusively to turning bog standard phrases like " that monkey has a big head" into Latin.

Mon, 23 May 2011 14:17:39 UTC | #629871

Carney's Avatar Comment 10 by Carney

I must say this surprises me. Don't (or didn't) much more primitive animals, from tyrannosaurs to sharks to moths, have a keen sense of smell? Isn't it the case that primitive animals have a much higher proportion of their brains devoted to smell than to other functions? I would have thought smell and an emphasis on it to be a marker of lower intelligence rather than higher.

Mon, 23 May 2011 14:37:49 UTC | #629881

ConnedCatholic's Avatar Comment 11 by ConnedCatholic

I read somewhere not long ago of a theory that rather than language it was the development of the ability to aim and throw that caused the big increase in the size of humans' brains. This has some resonance with me.

Mon, 23 May 2011 14:54:19 UTC | #629888

Anvil's Avatar Comment 12 by Anvil

Comment 9 by Schrodinger's Cat

Comment 6 by Anvil

hominid encephalisation

There must surely be an enormous area of the brain devoted exclusively to turning bog >standard phrases like " that monkey has a big head" into Latin.

Who you callin' a Murnkey?

Anvil.

Mon, 23 May 2011 15:35:37 UTC | #629908

Anvil's Avatar Comment 13 by Anvil

Comment 10 by Carney

I must say this surprises me. Don't (or didn't) much more primitive animals, from tyrannosaurs to sharks to moths, have a keen sense of smell? Isn't it the case that primitive animals have a much higher proportion of their brains devoted to smell than to other functions? I would have thought smell and an emphasis on it to be a marker of lower intelligence rather than higher.

You met my Granddad, then!

Anvil.

Mon, 23 May 2011 15:39:09 UTC | #629912

Anvil's Avatar Comment 14 by Anvil

Comment 11 by ConnedCatholic

I read somewhere not long ago of a theory that rather than language it was the development of the ability to aim and throw that caused the big increase in the size of humans' brains. This has some resonance with me.

You'll be a bloke Monkey, then, eh, ConnedCatholic?

Anvil.

Mon, 23 May 2011 15:41:00 UTC | #629913

ConnedCatholic's Avatar Comment 15 by ConnedCatholic

Comment 14 by Anvil :

You'll be a bloke Monkey, then, eh, ConnedCatholic?

Dont get the joke.

Mon, 23 May 2011 18:24:48 UTC | #629984

Anvil's Avatar Comment 16 by Anvil

Comment 15 by ConnedCatholic

Comment 14 by Anvil :

You'll be a bloke Monkey, then, eh, ConnedCatholic?

Dont get the joke.

Sorry ConnedCatholic, one day I'll get this comedy lark weighed off!

My point was that selection works on both sexes.

Anvil.

Mon, 23 May 2011 18:39:34 UTC | #629988

ConnedCatholic's Avatar Comment 17 by ConnedCatholic

Comment 16 by Anvil :

Comment 15 by ConnedCatholic

Comment 14 by Anvil :

You'll be a bloke Monkey, then, eh, ConnedCatholic?

Dont get the joke.

Sorry ConnedCatholic, one day I'll get this comedy lark weighed off! My point was that selection works on both sexes.

Anvil.

Oh I see. Yeah I'm a bloke. Interesting what you are saying. Which is if I get you correctly that if this theory is correct it would only be male brains that increased in size since they did the aiming. A bit more complicated than I was contemplating when making the post.

So do you think that there is nothing in this theory because of that? I was trying to find some logic to deal with male sperm passing on intelligence onto female offspring but infortunately I do not know anything like enough to continue the argument. And I only have a feeling that I know what you were getting at.

Perhaps you can explain it further but please in a slightly more straightforward way. No riddles if you can help it. I am basically a simple minded sort of person and it takes a while for things to click.

But don't let me put you off cracking a few more good ones.

Thanks. Mike.

Tue, 24 May 2011 20:25:26 UTC | #630424

DavidMcC's Avatar Comment 18 by DavidMcC

Although rodents may well have developed a larger brain for smell, later mammals, such as primates, developed even larger brains still to process the even larger amounts of (visual) information for identifying individuals by sight, rather than smell. Therefore, the wording of the article is slightly misleading, IMO.

Wed, 25 May 2011 08:55:02 UTC | #630644

jjoaquinv's Avatar Comment 19 by jjoaquinv

It's an intesting reading. In primates as human, vomeronasal organ is "atrofiated" because of the reduction in size of the nose and changes in the shape of their skulls. I always knew that mammals are victims of their smell: It guide them to the food, to the friends, to their couples... There's a lot of comunication codes, and the brain must evolve to recognize all. We're "smart" now because we've had one snouted ancestor. (excuse me, my english is rusted)

Thu, 26 May 2011 20:21:36 UTC | #631286

DavidMcC's Avatar Comment 20 by DavidMcC

On the othe hand, jjoaqinv, maybe we are smart now because our arboreal ancestors "abandoned" smell in favour of sight. IMO, it was a case of "too and fro" evolution. Vertebrates generally acquired a longer life after evolving a long-lived eye type, and this allowed time for a better organised brain to be possible, given the right circumstances, long before mammals existed.

Fri, 27 May 2011 10:39:16 UTC | #631475

DavidMcC's Avatar Comment 21 by DavidMcC

Another thing: early rodents were trapped in the dark for most of the time by the threat of predation by dinosaurs, and reptiles, which dominated the land in the Jurassic and Cretaceous. This made their eyes useless for most (though not all) of the time. Hence the sense that developed at that time was smell - eyes had to wait their next chance later in evolution, when we came out of the dark.

Fri, 27 May 2011 12:06:06 UTC | #631494

DavidMcC's Avatar Comment 22 by DavidMcC

Another interesting point is that bats evolved as nocturnal arborealists, so it was their hearing, not their sight or sense of smell that mattered most, and helped build their brains.

Fri, 27 May 2011 12:11:47 UTC | #631496

Alan4discussion's Avatar Comment 23 by Alan4discussion

Comment 23 by DavidMcC

Another thing: early rodents were trapped in the dark for most of the time ..... ..... .... This made their eyes useless for most (though not all) of the time. Hence the sense that developed at that time was smell - eyes had to wait their next chance later in evolution, when we came out of the dark.

Comment 24 by DavidMcC

Another interesting point is that bats evolved as nocturnal arborealists, so it was their hearing, not their sight or sense of smell that mattered most, and helped build their brains

..The BBC and other news media are carrying this story.

The part of the brain used by people who can "see like a bat" has been identified by researchers in Canada. Some blind people have learned to echolocate by making clicking noises and listening to the returning echoes. A study of two such people, published in PLoS ONE, showed a part of the brain usually associated with sight was activated when listening to echoes. Some blind humans have also trained themselves to do this, allowing them to explore cities, cycle and play sports.

Another interesting feature in brain evolution.

Fri, 27 May 2011 22:39:33 UTC | #631607

DavidMcC's Avatar Comment 24 by DavidMcC

That's a point I overlooked, Alan, in spite of the recent discussion of the subject! However, this flexibility in brain wiring simpy allows rapid adaptation to new stimuli, which helps avoid extinction in the short term. Over evolutionary time, parts of the brain can still expand in response to stimulus changes like that, without necessarily having to trade off against other parts. (Although that would be the "easy first option", presumably.) IMO, the main limiting factor in bat brain size would have been the fact that they rely on being able to fly, and bigger brains mean more weight to carry in flight.

Sat, 28 May 2011 10:32:40 UTC | #631665

Anvil's Avatar Comment 25 by Anvil

Comment 19 by ConnedCatholic

    Comment 14 by Anvil :

       You'll be a bloke Monkey, then, eh, ConnedCatholic?
    Dont get the joke.

Sorry ConnedCatholic, one day I'll get this comedy lark weighed off! My point was that selection works on both sexes.

Anvil.

Oh I see. Yeah I'm a bloke. Interesting what you are saying. Which is if I get you correctly that if this theory is correct it would only be male brains that increased in size since they did the aiming. A bit more complicated than I was contemplating when making the post.

So do you think that there is nothing in this theory because of that? I was trying to find some logic to deal with male sperm passing on intelligence onto female offspring but infortunately I do not know anything like enough to continue the argument. And I only have a feeling that I know what you were getting at.

Perhaps you can explain it further but please in a slightly more straightforward way. No riddles if you can help it. I am basically a simple minded sort of person and it takes a while for things to click.

But don't let me put you off cracking a few more good ones.

Thanks. Mike.

Yup, that was exactly what I meant, Mike.

I'm basically simple minded, too. It took a few books and a few long conversations with some hyper intelligent (and quite caustic) women to point out that the general model: 'Man the Hunter' or the 'Tarzan Hypothesis' had a number of penis sized holes in it and that - and I never knew this at the time - was complete speculation based on an incredibly limited amount of knowledge, and that further still (and, sadly, this is more or less a quote) It would be a far more productive use of my time if I were to start using my co-opted naturally selected brain to think like a Darwinian instead of utilising the contents of my pants.

It was in a pub. In public.

I was a bit embarrassed at the time, but I'm over it now.

Still, that said, big brains need protein, and the easiest way to obtain that is through meat. All those amino acids... Yummy! (And who do you think brought home that bacon, eh, Bitch! EDIT: See what happens when a woman points out a penis-sized hole to a man!)

Either way, whatever aggregation of things which dragged us into into our big brained cognitive niche - and, equally importantly, when, we may never know.

Speculation, is great fun though, and, although it may well be all we have, isn't it absolutely amazing that natural selection produced something that can speculate - through its knowledge of natural selection - that in its own past a niche vacated by the extinction of every living thing above five kilos, over 60 odd million years ago, led to the selection for binocular and colour vision that we have today?

It gobsmacks me, speculatively speaking of course, and in a way saddens me, that we may never know the whole story.

Then again, who, a few short years ago, would have thought that developments in the study of the human genome would unearth point mutations in mDNA that allow us to open a hitherto unknown (let alone unopened) window into the past, through which we can stare straight into the eyes of Mitochondrial Eve? Nothing speculative here.

And then, suddenly, and inexplicably, thinking of Eve, my mind wanders from the Darwinian mode - and I start to utilise the contents of my pants.

What was she like? Was she a bit of a cracker? A minger? Would she like football? If she was in front of me now, would I be looking directly at her tits - or would I have gone straight to the moustache?

Anvil.

Sat, 28 May 2011 10:53:22 UTC | #631666

DavidMcC's Avatar Comment 26 by DavidMcC

My "final answer" to the question of how senses compare as "builders of the brain" is that vision comes out top and hearing probably second. Why, because that is the order of the amount of useful information about the environment that they can provide. When the environment of a species is "starved of light", then other senses tend to take over from sight. I'm saying that this happened for rats and bats.

Mon, 30 May 2011 09:45:11 UTC | #632301

Troll's Avatar Comment 27 by Troll

Removed by moderator

Fri, 10 Jun 2011 20:39:50 UTC | #636950