Saturday, April 30, 2016

An Economic Explanation For the Evolution Of Intelligence

Comment on: Evolution Q&A: Why did only humans become intelligent? by Greg Stevens


You really did the theory of evolution justice!   I, on the other hand, really suck at doing theories justice.  Watch...

So... humans are exceptionally intelligent.   What is exceptional intelligence good for?  It's good for solving exceptionally hard problems.   But why did early humans, out of all the animals, need to solve exceptionally hard problems?    It's because out of all the animals, early humans had the greatest ability to (simultaneously) allocate the widest variety of resources.   This exceptional ability was the result of having hands, arms and... walking upright.

With quadrupeds... all four limbs are primarily dedicated to allocating a single resource... the animal itself.   But this specialization is a continuum that ranges from horses to raccoons to chimps.    Horses obviously have four legs.   All their limbs are quite specialized to allocating only the horse itself.  None of the horse's limbs are remotely capable of allocating other resources.    What about raccoons?  Do they have four legs?   Well, their front limbs are reasonably capable of allocating other resources.   Chimps definitely do not have four legs.   They have two legs and feet and two arms and hands.  They are quite capable of allocating other resources with their arms and hands.

As front limbs become less dedicated to only allocating the animal itself and more generalized to  allocating other resources... there's an increase in the total variety of resources that can be (simultaneously) allocated.  This creates a more difficult/complex allocation problem.... which requires more brain power/storage to optimally solve.   Well... a distinct advantage is given to exceptionally intelligent individuals.

Since you're fond of using lions as an example... let's compare them to zebras.  It would seem that the front limbs of the lion aren't as specialized to self-allocation as the front limbs of the zebra are.  Lions certainly use their front limbs to allocate themselves... but they also use their front limbs to allocate their prey.   But perhaps the biggest difference is that the mouths of lions are quite capable of carrying/allocating resources (food, cubs, other?).  Do zebras use their mouths to carry anything?   Not so much?  Therefore, lions are faced with more complex (allocation) problems than zebras.... and we should suspect that lions are more intelligent as a result.

So.... for lack of a better word... more "resourceful" body types put greater selection pressure on intelligence.   Humans are the most intelligent animals because our body types are the most "resourceful".


See also: video clips of animals carrying things


I really like this theory! It’s very thoughtful and interesting.

One question I have: how can this approach explain why octopods don’t have as advanced symbol manipulation and culture as humans. Surely more of their bodies is able to allocate resources more flexibly and in a greater number of ways, yes? - Greg Stevens


I'm hardly an octopod expert. When I googled "octopus carrying" I found this picture of a mom with 8 arms. According to the allocation theory she must be a lot more intelligent than us! Also found this cartoon of an octopus carrying different things. There seems to be a bit of disparity between fiction and reality though. I only managed to find this video of an octopus carrying a coconut. I added it to my playlist of different animals carrying things.

According to Wikipedia... octopuses are "highly" intelligent. But why aren't they even more intelligent? One explanation might be that they die after reproduction. No matter how exceptionally intelligent an individual is... it's not going to exert significantly more influence on the gene pool than any other individuals.

With early humans... exceptionally intelligent individuals were more likely to optimally solve complex carrying problems... which meant that they were more likely to live to produce many more offspring than other individuals. This shifted the gene pool in a more intelligent direction. With modern humans though it's a different story. Survival/reproduction is far less dependent on successfully solving complex carrying problems. Therefore, exceptionally intelligent individuals are not going to shift the gene pool in a more intelligent direction.

We've reached peak intelligence! Of course this might change if we start seriously colonizing space.

With octopuses there's also the issue that they don't seem to have 100% control over their limbs! We have far less "carrying parts"... but we do have 100% control over them.

Perhaps another issue is that carrying things in water is easier than carrying things on land. This means that there's less of an energy cost when the wrong things are carried in water. Of course in both land and water the opportunity cost is equally high when the wrong things are carried.

Also, octopuses don't have a very distinct division of labor between carrying limbs and locomotion limbs. As the saying goes, a jack of all trades is a master of none. As humans we have legs for walking and arms/hands for carrying. So we maximize two factors... distance and difference. We can carry the widest variety of different resources over the greatest distances. I'd bet that any aliens that visited our planet would have, or used to have, a similarly distinct division of limb labor.

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