While being called
a "pea-brain" is usually taken as an insult to one's intelligence,
absolute brain size or mass does not directly relate to how "smart"
a person is. For instance, if a human brain were massed against an elephant brain,
the elephant brain would most likely have a reading of around 6000g compared
to the measly 1300 g human brain. However, elephants aren't able to add numbers
or understand Shakespeare (wait a minute, who can understand Shakespeare?) -
they barely possess anywhere near the vast and complex mental capabilities of
humans. Generally, larger animals have larger brains to control things like larger
muscle mass, but more brain does not mean more intelligence. Thus, size does
not matter . . . or does it?
Much attention
has been paid to the size of the brain in comparison to the body of its owner.
Scientists have found that what generally differentiates the brains of species
with higher and lower intelligence is not the absolute mass of the brain, but
a special comparison of the mass of the brain to the mass of the body. This brain/body
ratio is called an encephalization quotient. The elephant may have a massive
brain compared to ours but not in relation to its body. Many scientists have
concluded that species with a higher brain to body ratio are more intelligent.
However, this conclusion is debatable since the tree shrew, a mouse-like animal,
has the largest brain to body ratio of all mammals. Its brain is around 3% of
its body weight while a human brain is approximately 2.3%.
More important
than brain/body ratio is the complexity of the brain. Things like the type and
number of neurons and number of synapses are what intelligence researchers have
found to be consistently linked to a person's intellect. For instance, areas
such as the frontal lobes, responsible for complex characteristics and activities
such as personality and problem-solving capabilities, are more highly developed
in species we view as more intelligent. These areas have a greater number of
neurons, glial cells, and synapses. The neurons and glial cells are also larger.
Interestingly, dolphins have been discovered to exceed humans in the intricacy
of brain structure, a wrinkle to the theory of brain complexity linked to intelligence.
Perhaps dolphins are smarter than humans, but on a different level and thus rendering
our perception of intelligence false and useless. On the contrary, perhaps we
are looking for the wrong differences between those of superior and inferior
intellectual capabilites. Humans may be relatively intelligent, but we still
have a lot to learn.
