Perhaps the most important limitation of brain size is the fact that brain tissue is metabolically very intensive and it, therefore, consumes a lot of energy. The heart, the liver and the kidneys need a similar amount of energy per gram of tissue. However, their size is much more determined by body weight than brain size i.e. it varies much less between species. Other organs, bones, muscles, skin etc. consume per gramme a fraction of the energy the brain consumes (…)
That means that it is more difficult to achieve a certain increase in brain size through natural selection than it is, for example, to achieve an equivalent increase in muscle mass or general body size.
Another difficulty is that an organism cannot temporarily shut down its brain to save energy because the brain needs exactly the same amount of energy at rest.
(Carel van Schaik, Karin Isler 2010: Gehirne, Lebensläufe und die Evolution des Menschen, in: Fischer/ Wiegandt: Evolution, pp. 142-169, pp. 153s)
The brain is a very expensive organ for a living organism because it consumes a lot of energy. Nevertheless, in mammals, primates, monkeys, great apes and finally hominids all the way up to humans, a steady increase in relative brain size can be observed.
beginning, two statistics related to energy consumption should make the costs
of the brain clear: 1. The brain is responsible for approximately 20% of the
total energy consumption of the body. 2. More than 50% of the energy that the
human foetus absorbs is used to build up its brain.
three authors who have weighed in on the issue of the costs of the brain in the
context of human evolution will have their say. Robin Dunbar, from whom I used
the first percentage, wrote:
Brain tissue is unusually expensive to grow and maintain. It needs about ten times more energy than one would expect, based on its weight, and it is the most expensive tissue after that of the heart and liver.
the emergence of human culture and the cultural ability of modern humans,
something new and unprecedented is emerging.
Why does culture develop? The mind? What are the reasons? What is the cause for this innovation that will fundamentally change the world of the human species? How did the brain become the basis of the human mind through a functional change?
second question: What is new? How can we specifically describe the new issues
that arise? In his review of Tomasello’s book The Origins of Human Communication, Jürgen Habermas writes:
After the increases in size of the human brain had stopped, cultural learning processes replaced genetic adaptation. What other animal species lack is the transfer of symbolically stored knowledge from generation to generation, such that it can be revised and expanded in the light of new experiences.
(Jürgen Habermas 2009; Es beginnt mit dem Zeigefinger, in: DIE ZEIT No. 51/2009 of 10 December 2009, p. 45)
The first task is to describe the biological mechanisms that led to the development of the human brain. The biological causes for the development of the human brain, brain growth and the end of thereof must be explained before the beginning of the cultural achievements of Homo sapiens are explored.
second task is to describe how the existing human brain, through a functional
change, could become the biological basis of the mind.
can’t make out the details of an object well enough, I would make use of a
magnifying glass. If I still want to be able to see finer details or material
structures, then I’ll use a microscope. If I want to research a subject
scientifically, one possible method is to divide the subject into many small
problem areas, each of which can then be examined individually. In the end, the
results are combined once again.
brain is the biological seat of the mind, the two are therefore not identical
to each other.
Moreover, the mind has its own identity, which must be explored and described. The basic form of the mind or culture arose in a special historical situation. With the mind a new level of existence was born,
characteristics of individuals and social groups arose; characteristics that
can no longer be adequately described with the biological theory framework but
which require the use of humanities or social science theories.
In The Cultural Origins of Human Cognition,
Michael Tomasello drew attention to what, on an evolutionary scale, was a short
period of up to 250,000 years, during which man’s cultural development has
taken place up to this day.
We know from embryonic development, and Darwin has stressed in great
conclusions about phylogenesis can be drawn from the ontogenesis of individuals of today. Why shouldn’t this line of reasoning be applied to brain and mind?
Every infant already has a human brain before it can absorb cultural
stimulation from its environment. This should also apply for phylogeny, the
tribal history of humans. The chronological sequence of brain and mind
development is basic but raises new questions about the development of the
From the moment the human brain exists in its present form, there is
the possibility of the emergence of the human mind and human culture – but only
As the basis of the human mind, the human brain is an evolutionary innovation that couldn’t have developed gradually but rather only through a change of function. The co-evolution of mind and brain is replaced by another model of thinking, that of the temporal succession:
the human brain developed, then the human mind developed. First the human brain
had to be created for biological reasons. Only then could the human brain
become the basis of the human mind through a change in function.
biological basis of the human mind is the human brain. Therefore, the
development of the human brain is a central question in the development of
human culture and the human mind.