Church of God, New World Ministries

Animal Brain Vs. Human Mind - Part 4

In our last articles, we analyzed the similarities and differences between the mental activities of humans and animals. We demonstrated that human thought is enormously superior to animal thought.

We analyzed the similarities and differences between the physiological brain of humans and animals. We are demonstrating that the human brain is only barely superior to animal brain, we explain the enormous superiority of human mental activity in the light of the bare superiority of human physiological brain – and begin to answer the ultimate question: What is man?

Our imaginary scientific friends haven’t moved – they are too stunned – and frightened. The physiologists stood stupefied, numbed by man’s astounding mind. The psychologists set numbed stupefied by man’s ordinary brain.

There seemed to be only one way of solving their dilemma.

The human mind greatly surpassed what could not even be called “animal mind.” But the human brain was only barely superior to animal brain. How, then, could the incredible human mind be explained if not by the physical human brain?

Was there any choice?

A non-physical component seemed to exist in the human mind. How could these imaginary researchers (from the “n-dimension,” remember?) maintain even a shred of their much- professed intellectual honesty and not admit that the human mind contained a non-physical component?

With this article we thanked them for their help and bade them adieu.

Now let’s consider the cosmological import of their conclusions. Imagine the consequences if man indeed possesses a non-physical factor: our individual lives – indeed our whole society – would have to be restructured. And time is running out. So, considering the awesome significance of such an intimate non-physical reality, we would be absolutely sure of its existence.

You may not have guessed it. But there are three general types of people reading this series on the human mind. The first group has always been convinced that the human mind is simply the product of the human brain – with absolutely nothing non-physical involved. For them no proof would ever really be acceptable. The second group has always assumed that a non-physical component does exist in the human mind. For them no proof was ever really necessary.

It is to the third group that this present article is addressed. These are people at all levels of society and education who are not bound by either dogmatic view. These are people who think – people who demand factual data, logical reasoning and the truth.

And we challenge this third group to determine the truth: Is there, or is there not, a non-physical factor in the human mind? Consider the evidence, analyze the arguments – and then decide.

At least to some degree, mental capacity is proportional to brain size. Brain weight and intelligence increases from rat to rabbit to cat to chimp to human. But there are mammalian brains much larger than the human brain – like the brains of whales, dolphins, and elephants. What about these mammoth, well-structured brains? They require thorough investigation.

Now it would betray incredible ignorance to immediately conclude that, since man’s brain is smaller than a whale’s brain and since human mental activity is much more profound than whale mental activity, man must have a non-physical factor. We must investigate in detail.

Whales especially stand out when mammalian brains are compared by gross weight. A sperm whale brain can weigh 19.6 pounds – that’s more than six times the three-pound human brain and 20,000 times more than the 0.0009-pound mouse brain.

Many elaborate formulas have been devised to portray the relevance – or more precisely the irrelevance – of gross brain size. Naturally, the huge brains of whale and dolphin cause some anxiety to the materialist. Nonetheless, he has his apparent explanation

The traditional (and most simple-minded) interpretation of the brain weight-intelligence relationship is this: brain weight itself is not as important as the brain weight’s percentage of total body weight. On this scale, man surely ranks highest – or so we are led to believe – his brain being 1.8% of his 165-pound body weight. Chimp brain is about 1.0%, sperm whale brain 0.03%, and blue whale brain 0.0005% of its 300,000-pound hulk.

Though this theory seems logical – and is indeed partly correct, it rapidly breaks down. Among cetaceans (whales, dolphins, porpoises) – whose mental capacities are almost indistinguishable from one another – the brain weight percentage varies almost 200 times from 0.86% (porpoise) to 0.005% (blue whale). This variation is about 100 times greater than the difference between man and porpoise. Are porpoises 200 times “smarter” than blue whales? And are men only twice as “smart” as porpoises?

Without wasting any more time, the capuchin monkey of South America blows the theory apart. Its brain weighs 5.7% of its total body weight – over 200% more than the human brain-weight, body weight ratio. Does that mean this little monkey is 200% more intelligent than human beings?

Other systems such as the ratio of total brain weight to body surface area or brain-stem or frontal-lobe weight may seem more valid at first – but soon turn out to be just as ineffective in explaining the superiority of the human mind.

Let’s get more specific. The entire brain isn’t responsible for consciousness, personality, and intelligence. It is primarily the cerebral cortex. The cerebral cortex is the thin – average 1/6-inch outermost layer of the brain. It contains the cell bodies of billions of nerve cells. Whenever you view an exposed brain, everything you actually see is this thin cerebral cortex. It is convoluted (folded and furrowed) in order to compact a large surface area into a small volume.

Scientists have differentiated two general categories or cortex: One is the “specific sensory projection cortex,” which receives, processes, and analyzes the direct sensory information (visual, auditory, tactile) coming from the outside world. The other is the “intrinsic cortex” (sometimes called “unspecific” or “association” cortex), which has no direct communication with the external environment.

Intrinsic cortex can be split into two distinct regions: “posterior intrinsic cortex,” which is involved in sensory associations and problem-solving, and “frontal intrinsic cortex,” from which thinking in the sphere of time, social awareness, and the “will” originate. Intrinsic cortex, then, is the seat of the highest mental activities. It is a key area for human thought.

Man has a large cerebral cortex, extensive intrinsic areas, and a massive frontal region. Consequently, it is logical that man is somewhat more mentally advanced than mere brain size suggests.

In fact, it is the relative proportion of intrinsic cortex which is critical. Too much specific cortex “clutters up” the brain – much as numerous local radio stations will limit the range of a superpower station – thereby not allowing the intrinsic cortical areas the “unjammed freedom” necessary for the generation of cognitive, symbolic, and abstract thought.

So it is the ratio (percentage) of intrinsic cortex to total cortex (as well as the total amount of intrinsic cortex) which is crucial. This percentage is roughly 10% in rat, 50% in cat, 75% in monkey, and 95% in man. Recent data indicates that the percentage of intrinsic cortex in whale and dolphin are roughly the same as in monkey. This means that whale and dolphin have a greater amount of intrinsic cortex than man, with very close to the same ratio. How then could man’s small advantage in ratio more than offset his considerable disadvantage in amount?

Professor Slijper reports that cetacean (whale, dolphin, porpoise) brain, aside from its size, is remarkably similar to the human brain. He emphasizes that cetacean cerebral cortex is exceptionally convoluted (just like the human brain) and extends so far back that in the common dolphin it completely covers the cerebellum at the rear of the cranial cavity (again, just like the human brain). Slijper contends “these convolutions are not only very striking in appearance, but are an essential criterion for judging the stage of development a given brain had reached.” He sums up his impression by facetiously asking: ‘Must we assume that porpoises, sperm whale and dolphins, by virtue of their highly-developed brains have the capacity akin to those of man?” Brain capacity – yes. Mental capacity – no. And that’s the point.

Perhaps the most knowledgeable assessment of the cetacean brain comes from Lawrence Kruger’s chapter in Whales, Dolphins and Porpoises. Kruger immediately stresses the “remarkable extent of fissuration (convolution) of the cetacean cortex.”  He connects older reports which described an extremely thin cetacean cerebral cortex.

Debunking this theory, Kruger shows that the crucial top layer of the cerebral cortex – the molecular layer - is extraordinarily thick in cetaceans (350-500 microns), more than double that of comparable animals and in the same range as man?

It is classically thought that the primary criterion of intelligence is the amount and ratio of intrinsic cerebral cortex. Therefore, some scientists expected cetacean brains to have a small ratio of intrinsic cortex – and this would have explained man’s enormous psychological dominance. Sorry, Kruger proved that the dolphin’s ratio parallels that of the higher primates.

Now since the size of cetacean intrinsic cortex is larger than the homologous human cortex, and its ratio is very close to man’s, what then, gives the human brain any superiority at all?

Kruger proposes the answer. But his cogent reasoning is even more interesting. To understand either, we must first learn about the microscopic appearance of cerebral cortex. The cell bodies of the billions of neurons seem to be horizontally arranged in various layers – called “laminars.”

As mammals increase in mental complexity from rabbit to cat to chimp to man, there is a general tendency for these laminars to become more stratified and more distinct. Now what about the cetaceans? Well, brain research has finally uncovered the long-sought “good criterion for insisting upon man’s superiority.” Because in cetaceans this laminar arrangement is largely absent. Notice how Kruger phrases his conclusion:

“If we were forced to choose the criteria of greatest relevance to intellectual development, the mere fact that three mammalian orders (Cetacean, Primates and Proboscidean {elephants}) presumably develop extensive “association” cortex would seem to suggest that the degree of laminar differentiation is the most evident characteristic that can be claimed for superiority in the human brain, unless one wishes to claim that dolphin and elephants are as clever as man.”

Why, asks Kruger, are human begins mentally superior to whales, dolphins, and elephants when the brains of the latter are enormously larger in size and almost equal with respect to all the traditional standards?

Kruger has no alternative – he has only one viable point in which human brain is supreme: laminar differentiation – human cortical cells are arranged neatly in layers.

Circular reasoning has dictated this judgment – and Kruger tells us so! His logical appraisal is as sound as it is forthright and honest. He knew that man’s brain must be the most advanced – yet he saw every traditional neurological yardstick deny it. Though other authors would cling to these ill-advised criteria – which supposedly prove human brain superior to cetacean brain when in fact they suggested quite the reverse -  Kruger candidly eliminated them. As a result, he had to nominate the only conceivable way in which human brain could possibly be supreme: the arrangement of human cortical cell bodies in layers and the absence of such laminar stratification in cetacean cerebral cortex.

Why should laminar differentiation make such a spectacular difference in the mental output of rather similar brains? It doesn’t matter. Experimental evidence or theoretical justification never had to be considered. There was no other choice! In contradistinction to all too many scientists, Kruger makes the reader aware of his solid reasoning procedures –and we appreciate that.

In conclusion now, what have we learned from cetacean brain? Slijper states that the whale brain almost equals the human brain. Neurophysiologists have notoriously strained to ascertain why these huge, highly complex cetacean brains are not actually superior to human brains. And Kruger must utilize circular reasoning to prove that the human brain is even slightly more advanced, employing a “last-resort” laminar analysis of cerebral cortex to do so, after negating all the other so-called “proofs.”

Obviously, the human brain is physically superior to any cetacean brain. We’ve never doubted that fact, Kruger’s right. He makes his point.

 But this is our point:

If Kruger had to brilliantly struggle to keep the human brain just barely superior to cetacean brain, how then can anybody explain by physical means alone the yawning chasm between the unrestrained mental activities of human beings and the stereo-type instinct of porpoises, dolphins, and whales?

It is physically impossible. A non-physical factor is demanded.

Be watching for the next installment in which we learn why there is a vast difference between human brain and animal brain.

 
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