If Modern Humans Are So Smart, Why Are Our Brains Shrinking?

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Intelligence is different from brain size. How do we know that the extra area of the Neanderthal brain wasn't directed towards survival tactics?

A lot of scientists seem to agree that the Neanderthal Brain structure and mass lead to to have poorish coordination skills but excellent memory capabilities.

Almost makes them sound on the spectrum in some respects. There is even a theory related to it, but I believe it is incorrect.

You dont need to be very intelligent to survive.. you need to be economical and practical. Ergo, memory intensive with a dash of smarts.

you know chimpanzees beat college students in short term and long term memory recall of things they were shown only once & for a few moments?

Human quality of life has increased to the point that weak, stupid people are no longer being killed off, so they are allowed to proliferate. Stupid people reproduce more than smart people due to carelessness in having sex among other factors. That may sound like an anti-humanist, Hitleresque point of view, but it makes evolutionary sense. I'm not a Nazi, but nature is.

New Research shows that the Achilles Tendons of Homo Neanderthal were not evolved for fast, long distance running or walking, as used by Homo Sapiens Sapiens for migration or persistence-hunting. Neanderthals couldn't migrate a distance as quickly as S.Sapiens, and in the hilly terrain of central europe persistence-hunting was less effective than ambush-hunting, which the Neanderthals preferred.

With new reaearch accumulating, Neanderthals seem more and more like Modern Humans, they could have produced a proto-language, definitely made art or symbolic artifacts like seashell necklaces, made use of fire, buried their dead, and hunted in a manner signifying intelligence and anticipation of their preys behaviour. Difference is only that they evolved a few different physical attributes, that meant they needed different techniques to survive. When the environment changed with the next advancing/retreating ice age, Neanderthals had less survival advantage than Modern Humans and so Humans out-competed them. But that doesn't mean Neanderthals were hunted by S.Sapiens to extinction - people of european descent have roughly 4% of Neanderthal DNA in their genome, meaning extensive cross-breeding occurred.

As for changes in size of the Human Brain, Consider "Sexual Selection" pressure alongside "Natural Selection" pressure. Also read "Collapse" by Jared Diamond, especially the part on intelligence vs disease resistance.

Miniaturization is a sign of increasing sophistication.

Are humans becoming any less intelligent than they have been in the past?

ruveyn

Wrong, there still is a relation. The basic idea is that the larger an animal, the more brain matter it needs in order to control the body and so the excess brain matter might be used for higher cognitive abilities. A simple ratio is only a rough estimate of this though and it does not take allometric effects into account, so it's not surprising that Homo Habilis and Homo Aferensis were not as advanced as Floresiensis. A better measure and more refined measure is the encephalisation quotent (EQ) and I think should account for the differences you've mentioned.

Sources:

http://en.wikipedia.org/wiki/Brain-to-body_mass_ratio

http://en.wikipedia.org/wiki/Encephalization_quotient

It could be a case of humans losing functionality in the brain that is no longer needed while increasing the efficiency of cognitive functions at the same time. Although, it does seem like the human brain size has started to increase again slightly in the last 200 years or so.

miniaturization is a part of the evolution of efficiency.

..when did I say anything about intelligence being required to survive? I was talking about hunting tactics and such....

unlike animals, humans and our hominid ancestors require long periods of time before our brain is not only fully grown but also capable (internal wiring) of learning those hunting and survival tactics.

the closest animal to a human is a chimpanzee. When they are born their brains will be fully grown and developed within a year. Human brains take nearly 20 years until they are fully grown and developed...and it would be around age 10 that a human child can actually process enough information to do basic survival and hunting on their own.

we do not have 'survival' or 'hunting instincts' .. its all learned behavior. Even animals depend on learning skills from their parents to do things effectively... like you see lions or eagles having to be taught how to hunt after being raised in captivity..if they were released in the wild as is they'd starve.

learned behavior requires a bit of cognition and a decent memory.

That presumes there is a reproductive advantage to the compactification of our wet-works. While some change to allele frequencies are due to random genetic drift, most occurs because of natural selection and that hinges on improved reproductive performance. Right now humans perform reproductively without any enhancement of our intelligence or mental proficiency.

ruveyn

i understood up to there.
then... what does that mean? i know what "compactification" means, but i had to look up what "wet works" means, and i found that it was a euphemism for "murder". (euphemisms are unfathomable to me (especially when they are a crucial element of something i want to understand)).




i think "reproductive performance" (better described as "propensity for reproduction") is a conglomeration of many dynamic precursors. one of those precursors is "efficiency of operation in action".

one may have a physiological advantage over the mean physiological capacity of competing species (such as long necks in giraffes), but the energy required to perpetuate a superior physical system for attainment of resources must be taken into account.

maybe the energy spent in utilizing a physical advantage is almost equal to it's "energy saving" justification for it's utilization in the first place in some cases.

just as computers have followed the natural evolution of optimization which is inevitable, so does every thing else in nature follow a tendency toward optimization (within a system that is in equilibrium).

i believe the average human brain has around 100 billion neurons, but each of those neurons can communicate with only about 5,000 - 7.000 other neurons. that is a paltry wiring system. it takes a lot of energy to think because the "hand over" procedure from the 2 most disconnected neurons in the brain may take years.

if every neuron we possess was somehow directly connected to every other neuron we possess, without the need for neuronal "relays" then our brains would be very small and exceptionally efficient. the calorific requirement for sustenance of the surplus brain material would drop, and it would yield survival benefits for whatever species follows the inevitable path of optimization.

Microprocessors. They keep getting faster and smaller. Same thing.

Organic brains function through neural parallel processing.. something computers are just slightly starting to be designed to imitate.

Then there's the little known fact we actually have 3 brains: cerebellum and the cerebrum which is split into left and right halves; each half can function independently. So we have 3 brains each of which has individual regions that process different things all reporting to a central control are of the brain that is located in both halves of the cerebrum... its an amazing example of efficient flow and processing of massive amounts data in hardware that has multiple redundancy built into it.

I don't think modern humans in general are smart at all. So what if we have opposable thumbs or can learn to read and write and use fire? The world is worse than ever because of us. We're still having several wars in which the terrorists ARE winning, there's still plenty of racism and sexism and bullying and stigma towards people with ASD, disabilities or mental illness, we're overly populated the world, parents are clueless about raising their kids, there's still murder and greed and waste. People think being an alcoholic or a druggie is "cool", TV and movies are now terrible, and people care more about whatever recent act of stupidity Justin Bieber has recently committed than things that are actually important. We might be more educated about science and yet people still firmly believe in demons and god and witches and angels. We've been told why vaccinations against disease is so important but parents are terrified their kids will become autistic and think it's some government conspiracy to make them that way and now there are outbreaks of diseases that were once really rare and are a LOT worse than autism. I'm worried that people will start thinking vaccines for their pets is just as bad and we'll have a lot more animals with rabies or feline HIV. Why is it we're smart enough to ask questions about things but not enough to find the answers?