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article imageOp-Ed: Bigger brains not better – New study shows flaws in size theory

By Paul Wallis     Oct 9, 2014 in Science
Sydney - New studies have shown that rats and mice, which have very different brain sizes, have similar intelligence. A new study suggests that the assumption of brain size as a measure of intelligence was an intuitive, but wrong, assumption.
Cold Spring Harbor Laboratory scientists, thinking that mice would be good, economic test subjects, conducted a challenge test using auditory stimuli, and discovered that the mice performed as well as the rats.
It should be borne in mind that the use of rats in lab tests is now standard. Any routine methodology may take a while to question, let alone overcome. It’s an interesting point, though, that the size of the brain isn’t an indicator of intelligence, and it’s backed up by a few basic issues which are rather hard to overlook.
The theory of “primitive” brains has always had a few holes in it. Dinosaurs, for example, are considered dumb, partly because of the size of their brains, relative to their bodies. This theory avoids a few issues:
1. They were dinosaurs, requiring the brains of dinosaurs to survive in their environment.
2. They’d been evolving for millions of years, and their brain functions would have also had to evolve to meet changing needs.
3. They were arguably the most successful form of large animal life ever, so it’s unlikely that their brains were any sort of handicap.
4. The argument that body size affects brain performance doesn’t really stand up to a lot of scrutiny when you consider those brains had to manage 40 metre, multi-ton bodies, avoid predators, and find food. If their small brains were a disadvantage, how did they survive at all?
The use of brains
The real definition of brain power is function. Animal intelligence, like human intelligence, has to meet functional needs. Does a dog or a cat need a bigger brain? No, it needs a brain which helps it to live the life of a dog or a cat.
The “bigger is better” argument doesn’t last too long in other terms, either. Ants, for example, have existed for hundreds of millions of years, as corporate entities, with very small physical brains, and are also highly evolved, and functionally very efficient. Is it likely that brain size is a valid criterion for assessment of intelligence?
My theory is that brains evolve on the basis of efficiency, related to needs. Our basic idea of any efficient system is a stripped down system, with no superfluous parts. This type of system is minimalist, but it works.
Doesn’t it stand to reason that as brains evolve, they become more efficient at basic tasks? Ants can read a virtual recipe book of chemical signals with tiny brains. Wouldn’t a hundred million years or so of evolution essentially redesign a brain to work better?
The human autonomic nervous system performs thousands of tasks every second, without conscious thought. Imagine if you had to consciously manipulate every nerve cell to drink a cup of tea. Hardly efficient, is it? It’d take days, or perhaps years, to drink that cup of tea.
In practice, the division of labor between brain and nervous system is a lot more realistic and functional. These tasks are delegated from the brain, which is a much more efficient process. Body operations certainly do have a direct relationship to the brain, but a lot of the actual work is done without much higher brain function being required. Perhaps they were originally brain operated functions, but obviously, they're not, now.
Taking on extra functions requires more brain power, OK, but the basic need for efficiency means those functions and the brains managing them must become more efficient. Brains don’t remain unchanged forever, in any species, particularly Homo Sapiens, which has had several changes of size in the past, (not that you’d ever guess).
As far as this theory goes, brain size may actually be a measure of inefficiency or under-evolved development. The theory of evolution indicates that higher biological efficiency is a primary survival asset. Some of evolution’s biggest successes, ants and termites, which live in all environments, function perfectly with small, but fully functional, brains.
A “primitive” brain may be said to be a brain which hasn’t developed. The animals we’re calling “primitive” have had millions of years to develop their brains. Rats and mice, in fact, are among the most successful forms of mammals. They’re ubiquitous, able to survive a huge range of predators and human extermination attempts.
Digressing to the technical side for a minute — if a mouse shows the same level of intelligence as an animal with a bigger brain, you’d have to say the functional intelligence was on a par. It’d be interesting to check out the neural systems involved in this finding, to see the similarities and differences.
The scientists have created some more work for themselves here. It’s not enough to say that a small brain performs as well as a larger brain. How? Why?
Don’t expect to hear the end of this argument any time soon. As someone with a brain once said, “The more you know, the more you realize you don’t know.” That’s a measure of intelligence.
This opinion article was written by an independent writer. The opinions and views expressed herein are those of the author and are not necessarily intended to reflect those of
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