Did Neanderthals have bigger or smaller brains than humans?

[John_Mace]

@moriah

2-3% is a lot for DNA. We’re only separated from chimps by 1%. And if Neanders and Sapiens already had a lot of DNA in common, that again makes just 2-3% rather significant.

No, those are two different things.

I may, literally, have 0% DNA from my great-great-great-great-great-great-grandfather, but I think I’m more closely related to him than I am to a chimp.

This thread I started 10 years ago might help.

[carnivorousplant]

@moriah

2-3% is a lot for DNA. We’re only separated from chimps by 1%. And if Neanders and Sapiens already had a lot of DNA in common, that again makes just 2-3% rather significant.

Yes, but at first thought it gives credence to the theory that more were killed off that assimilated. I wonder how the size of the populations of Sapiens and Neanderthalis compared.

[BigT]

@John_Mace

Some scientists have interpreted this as simply the brain mimicking the skull shape for balance purposes, and recently some have suggested that this means Neanderthals sacrificed some of the “social brain” (in the front) for the “visual brain” in the back, and this is what led to their demise. I find the latter claim to be :dubious:

Part of the logic though is based on the fact that Neanderthals had, at average, 6mm larger eye sockets, meaning more “visual brain” would be necessary to process all the extra information they were geting. At least, that’s what the BBC article I saw yesterday said.

[FuzzyOgre]

Brain size isnt that critical.

I’m about 100 kg, and my head diameter is 63 cm. I know people that are 50 kg and much smarter than I. The same principle should apply on a species level scale.

[John_Mace]

@BigT

Part of the logic though is based on the fact that Neanderthals had, at average, 6mm larger eye sockets, meaning more “visual brain” would be necessary to process all the extra information they were geting. At least, that’s what the BBC article I saw yesterday said.

Yes, that’s the hypothesis. But the early members of our species had the same brain size as we do, and their archeological sites don’t look any different that Neanderthal sites. I’m just very suspicious of these types of explanations that seem to focus on one or two isolated things as if that could tell us the whole story of something as complex as why a species went extinct. Neanderthals were quite successful for tens of thousands of years, then they disappeared rather quickly when we arrived on the scene.

[Ulfreida]

Maybe they were simply less aggressive.

[Oly]

@John_Mace

The average Neanderthal brain was bigger than a modern human’s (not by much), but there’s a lot of overlap. Also, and probably more importantly, the shape of the Neanderthal brain was different. Theirs was longer and lower.
:

What do you mean by “longer and lower”? And does this refer to the hemispheres only, or the whole brain including brainstem and cerebellum?

[DSeid]

Hey “size matters” but it isn’t everything … organization counts too. It likely mattered not just how smart they were but how they were smart. Different sorts of intelligences perhaps.

[John_Mace]

@Oly

What do you mean by “longer and lower”? And does this refer to the hemispheres only, or the whole brain including brainstem and cerebellum?

Longer, from front to back, and lower from bottom to top. They didn’t have the nearly vertical forehead characteristic that we do.

[engineer_comp_geek]

@Oly

What do you mean by “longer and lower”? And does this refer to the hemispheres only, or the whole brain including brainstem and cerebellum?

Size and shape comparison:
http://library.thinkquest.org/26070/media/eng/231.gif

From this page:
http://library.thinkquest.org/26070/data/eng/2/3.html

[TriPolar]

@DSeid

Hey “size matters” but it isn’t everything … organization counts too. It likely mattered not just how smart they were but how they were smart. Different sorts of intelligences perhaps.

I think with sizes so similar, size doesn’t matter at all. And isn’t size relative to total body size the factor that would matter anyway?

[John_Mace]

@TriPolar

I think with sizes so similar, size doesn’t matter at all. And isn’t size relative to total body size the factor that would matter anyway?

Yes. It’s the organization of the brain and the interconnections that are made that matter. Unfortunately, brains don’t fossilize very well, so we can’t know much about that other than what we can glean from the cranial casts.

[DSeid]

As the cite in my first post notes anthropologically modern humans developed smaller brains during the Late Pleistocene. The argument that Neandertals were larger so needed larger brains seems trite. It requires a bigger processing unit to control a larger muscle than a small one? C’mon. The bulk of our motor cortex controls the small muscles of our hands and face, not the bulk of our legs and lats.

Smaller but “as good” may have just been an energy usage advantage and allowed modern humans to compete a bit more effectively. But the little we can understand about brain organization differences is still significant. They had larger cerebral cortices, relatively less of it frontal and prefrontal, and relatively smaller cerebellums.

That last part may seem odd to those who think of the cerebellum only as the “little brain” devoted to coordinating motor control … they had bigger muscles afterall … but it is now understood that the cerebellum does much much more. It is involved in the adaptive timing of many other processing streams as well and therefore critical to much of higher order cognitive processing.

See here:

In summary, the results of recent neuroanatomical, clinical
and neuroimaging studies have demonstrated that the role of
the cerebellum is not limited to motor functions but appears
to be involved in the modulation of a broad spectrum of
linguistic functions such a verbal fluency, word retrieval,
syntax, reading, writing and metalinguistics abilities. Based
on neural evidence and information processing theory, Leiner
et al. (1986) showed that the phylogenetically newest part of
the cerebellum (particularly the lateral portions of the cerebellar hemispheres and dentate nuclei) might interact with the frontal association cortex to allow for skilled manipulation
of information or ideas.

I am also (for fairly easily deducible reasons to anyone who investigates the link) a big fan of how this article about the neural dynamics of autistic behaviors describes the role of the cerebellum:

A key property of cerebellar learning is that it is adaptively timed, so that learned responses are emitted at times that are appropriate within the environmental constraints of the learning paradigm. Cognitive-emotional learning is also adaptively timed, so that motivated attention can be maintained on salient goal objects for the necessary amount of time to carry out goal-directed actions. Many goal objects may be delayed subsequent to the actions that elicit them, or the environmental events that signal their subsequent arrival. Humans and many animal species can learn to wait for the anticipated arrival of a delayed goal object, even though its time of occurrence can vary from situation to situation. Such behavioral timing is important in the lives of animals which can explore their environments for novel sources of gratification. On the one hand, if an animal or human could not inhibit its exploratory behavior, then it could starve to death by restlessly moving from place to place, unable to remain in one place long enough to obtain delayed rewards there, such as food. On the other hand, if an animal inhibited its exploratory behavior for too long while waiting for an expected source of rewards, such as food, to materialize, then it could starve to death if food is not, after all, forthcoming.

Thus, the survival of a human or animal may depend on its ability to accurately time the delay of a goal object based upon its previous experiences in a given situation. Such human or animal needs to balance between its exploratory behavior, which may discover novel sources of reward, and its consummatory behavior, which may acquire expected sources of reward. To effectively control this balance, the human or animal needs to be able to suppress its exploratory behavior and focus its attention upon an expected source of reward at around the time that the expected delay transpires for acquiring this reward. … [snip]

In summary, unless motivated attention and action are both adaptively timed, an animal or human could be condemned to either emit premature goal-oriented responses (as occurs in individuals with autism; see Section 3), or to generate maladaptive orienting and exploratory movements in any situation wherein a goal object does not immediately appear. Adaptively timed learning enables both attention and action to be appropriately timed to generate adaptive behavior in each environment. Evidence for adaptive timing has been found during many different types of reinforcement learning … [snip]

… adaptive timing in the cerebellum reconciles two equally important, but potentially conflicting, behavioral requirements: Fast allocation of attention to motivationally salient events, and adaptively timed responses to these events. …

My own WAG is that whatever changes occured the result was not more overall smarts but an improved ability to work as a team in more sophisticated ways.

[SCAdian]

@carnivorousplant

I worked with a guy at a library whose forehead shape had to be 25%.

Met a Navy commander whose forehead sloped sharply back - and he had a pronounced brow ridge, too. My first thought on seeing him was “Homo erectus!”

[Derleth]

DSeid: It’s nice to mark PDFs.

[DSeid]

@Derleth

DSeid: It’s nice to mark PDFs.

My apologies as I recall that bit of ettiquette, although like many rules of ettiquette I don’t quite understand why it is expected.

[carnivorousplant]

@DSeid

My apologies as I recall that bit of ettiquette, although like many rules of ettiquette I don’t quite understand why it is expected.

Nor do I.
This forum requires that you wait 60 seconds between posts. Please try again in 1 seconds.

[engineer_comp_geek]

@DSeid

I don’t quite understand why it is expected.

Back in the days of dial-up pdf files would take darn near forever to load. A pdf warning was considered good etiquette since an accidental click could leave you waiting for quite some time for it to load. The speed issue has mostly gone away, but acrobat is still an obnoxious piece of crap that locks your browser up until the pdf file loads. A lot of folks appreciate the warning.