Writer for letters to authorities, Calle Ayacucho, Cusco, Peru, 1989
Writer for letters to authorities, Calle Ayacucho, Cusco, Peru, 1989

Although the brain is a very expensive organ that consumes a considerable amount of energy, there has been a steady increase in brain size during evolution. According to Robin Dunbar, the larger brain of monkeys serves to establish social relationships with a larger number of individuals and to form a larger stable social group.

In the evolution of humankind, brain volume increased further but was limited by the width of the birth canal of women. This natural limit of brain growth was first circumvented by the postnatal growth phase of the child’s brain.

When these opportunities for brain enlargement were exhausted, evolution found a second way to overcome the limitations of the hominid brain. The brain of the individual did not grow any further but did communicate in a new manner with the brains of other group members, so that knowledge and tasks could be shared between the group members.

In this way, a network as we know it from PC networks, was created. With a larger postnatally completed and networkable brain, the biological premise for the evolution of the human mind was established. This is what we will now address.


Hypothesis 18


Quito, Ecuador, 1989
Quito, Ecuador, 1989

The network connecting the brains of a hominid social group is the second evolutionary solution, intended to overcome the natural boundary of the hominid brain (hypothesis 11).

The network that the current network-capable brains form initially serves only to expand the brain but not yet to expand the human mind.



Perhaps equally remarkable is the fact that since Homo sapiens reached this stage more than 100,000 years ago, there has been no further significant increase in brain size.

Reed boat, Titicaca Lake, Peru
Reed boat, Titicaca Lake, Peru

It is difficult to understand why natural selection gave primitive humans such a perfect brain that 100,000 years later it would enable the achievements of a Descartes, Darwin or Kant or the invention of the computer, trips to the moon or the literary creations of a Shakespeare or Goethe.
(Mayr 2002, p. 501)

Above, I posed the question as to whether Ernst Mayr is right with the statement of the perfect brain of Homo sapiens. Now here is the answer: Yes and no. He is right, because the human brain has found a miracle cure, so to speak, with its networking capabilities that enable it to access unlimited brain capacity via the network.

But Mayr would not have been right if his contention that the brains of Descartes, Darwin or Kant alone would have done their great work without the help of the human network of clever forerunners, critical contemporaries, interested discussion partners, etc. had been understood in such a way.

The end of hominid brain growth is a paleoanthropologically verifiable fact that is associated with the appearance of modern Homo sapiens.


Hypothesis 17

The end of brain growth

Uru Island, traders, Lake Titicaca, Peru
Uru Island, traders, Lake Titicaca, Peru

The beginning of the hominid brain network is the observed end of brain growth at the onset of Homo sapiens about 250,000 years ago.

The individual hominid brain does not need to grow because it communicates with other brains and outsources tasks and knowledge to the brains of other individuals: in other words, because it can form a network.


Merlin Donald speaks a lot about the network and the necessity to overcome the fixation on the individual.

Uru Island, Village Square, Lake Titicaca, Peru
Uru Island, Village Square, Lake Titicaca, Peru

But for him the network is objectively connected to the level of human culture:

With children, the acquisition of symbolic skills progresses from the outside to the inside. Therefore, their evolutionary development must have been in the same direction. Symbolic thinking and language are, by their very nature, phenomena that are founded in networks.

We therefore cannot explain their existence on the basis of the model of the solipsistically encapsulated individual. A paradigm shift is required. It needs to leave behind the prevailing theories of human evolution, according to which language has developed in the closed shell of the brain, that is, from the inside out. (p. 264)

Donald recognised that the scientific view of the individual or a group of individuals is insufficient and that in humans, the relationships between the individual group members are absolutely crucial.

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The fact that people form networks is probably not a very unique idea but rather a more commonplace one.

Reed soil, houses and boats, Lake Titicaca, Peru
Reed soil, houses and boats, Lake Titicaca, Peru

Evolutionary research talks a lot about groups, group activities, and joint actions but little about networks.

The focus is on the individual that we encounter in its archaeological remains and whose linguistic and cultural abilities are discussed within the contexts of being an individual and as part of the social group.

The concept of the network goes beyond the concept of the group, in that it addresses the individual group members in their individuality as well as their different relationships within the group.

Michael Tomasello talks a lot about the group and common activities and the common intentionality of prehistoric peoples. However, his argument appears to me to lack differentiation into distinguishable individuals with networks.

When determining the group size and the explanation, Robin Dunbar shows that he considers the number of relationships within the group without thinking about a possible network.


Hypothesis 16

Brain and network

Uru Island, Lake Titicaca, Peru
Uru Island, Lake Titicaca, Peru

The brain of an individual, previously only responsible for the integrity of its own individual, is given the additional function of enabling contact with the brains of other individuals in intentional communication, thereby circumventing its own limitations.

This results in an evolutionary change of function and an evolutionary innovation. The brains of individuals in the social group form a network, just as PCs make up a network.

And just as a network consisting of many PCs can solve tasks that would overburden the individual PC, a network of many human brains can solve larger tasks than a single brain.

The network is created to circumvent the natural limits of brain growth (hypothesis 11) a second time. It is created before the beginning of mind and culture and is also arranged in front of them as their prerequisite.


Blaffer Hrdy estimates that cooperative upbringing began

Rail journey to Lake Titicaca, Peru
Rail journey to Lake Titicaca, Peru

at the beginning of the Pleistocene epoch (about 1.8 million years ago) when the African Homo erectus appeared. The author drew this conclusion from the relatively small difference in size between the sexes compared to the much older Australopithecines.

The male Homo erectus were

only 18 percent larger than the females. This degree of sexual dimorphism is only slightly more pronounced than in modern humans. (p. 384)

The plausible interpretation of Blaffer Hrdy would mean that the hominids were looking after their young together long before Homo sapiens. Therefore, the use of human communication by the helpers and thus the whole group of Homo sapiens is very plausible.

Carel van Schaik and Karin Isler also emphasise the importance of the helpers in caring for the young:

In most mammal species, the mother is on her own during the strenuous gestation and nursing periods, so any help will save the mother energy.

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Rail journey to Lake Titicaca, Peru
Rail journey to Lake Titicaca, Peru

No mammal on Earth has produced young that take longer to mature or depend on the support of so many others than Pleistocene humans.

With the help of alloparents and parents, these offspring – incredibly costly and equipped with large brains – slowly grew up and enough survived to produce a population capable of penetrating into new habitats, raising children there, spreading further, and eventually populating the entire planet.

Nourished not only by their mothers but also by other members of the group, even descendants who were weaned long before they could care for themselves could slowly grow up without suffering hunger.
(German: Sarah Blaffer Hrdy 2010: Mütter und andere, Berlin, p. 377)

Because of the longer childhood and adolescence, the raising of the young has become extremely expensive for humans and their forerunners. Sarah Blaffer Hrdy, the originator of the quote, has dealt with the prolonged course of human life and its consequences.

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Hypothesis 15

Taking care of the young as a joint activity

Rail journey to Lake Titicaca, Peru
Rail journey to Lake Titicaca, Peru

Once the intentional communication and cooperation between the mother and the infant are established in a social group, all individuals go through this phase as infants and all female individuals experience it from the maternal side.

Since the mothers, as has been observed in various cases, would otherwise be overwhelmed with the task of raising the children alone, fathers, grandmothers, older siblings and other relatives also take on the responsibility of looking after and caring for the offspring.

These individuals will also use the new intentional communication they have experienced and which the infant demands from them when they communicate with the infant.

Since the new form of communication does provide advantages, adolescents and then later adults will playfully make use of intentional communication and cooperation. This is how the new form of communication will become established in the social group.


I therefore propose an alternative scenario:

Rail journey to Lake Titicaca, Peru
Rail journey to Lake Titicaca, Peru

the mother–child paradigm at the time of postnatal brain growth. The two facts that are missing in Tomasello’s work are mentioned here.

1. There is now a proposal for the situation in which the first step was taken: Postnatal brain growth led to the helpless human newborn, which was dependent on cooperation and intentional communication.

The situation was inevitable because it was predetermined by biological evolution, and it was permanent and not unique or accidental because all individuals went through this childlike stage of development. The situation therefore required some form of an evolutionary adjustment.

2. There is now a proposal for the individual who took first step. This was the newborn’s mother, who could only ensure the survival of the child through cooperative actions.

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Hypothesis 14

Mother and newborn 2

Funerery Rock, Machu Picchu, Peru
Funerery Rock, Machu Picchu, Peru

The newborn baby cannot develop its own activities; it orients itself towards the mother and tries to anticipate her actions and to share her intentions. This is the origin of the shared intentionality observed only in humans.

Intentional communication and cooperation have their phylogenetic origin in the communication and cooperation of mothers and newborns during the newborns’ helplessness in the first year of life.


The starting point of my considerations here is the study by Michael Tomasello on The Origins of Human Communication (German: Die Ursprünge der menschlichen Kommunikation Frankfurt/M. 2009). His comments on pointing gestures as the beginning of communication are convincing.

As far as the evolutionary beginnings of typically human communication and cooperation are concerned, however, I have come to different conclusions on the basis of theoretical considerations. Tomasello describes the phylogenetic origins in Chapter 5.

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For newborns it is essential for survival,

Temple Mount + Intihuatana, Machu Picchu, Peru
Temple Mount + Intihuatana, Machu Picchu, Peru

if they are not capable of acting themselves, then at least to understand those individuals who can act i.e. first to understand the mother and her actions and then later, if possible, to be able to predict her intentions i.e. to recognise her intentions and to behave in such a way that the desired care behaviour is achieved.

Likewise, mothers learn to interpret the behaviour of their newborn children and to recognise their children’s intentions and wishes. Here is the place where mentalisation first emerged and further levels of intentionality were tested, because they were absolutely necessary for the infant survival.


IV.    The networked brain

Hypothesis 13

Mother and newborn 1

Intihuatana + Temple Mount, Machu Picchu, Peru
Intihuatana + Temple Mount, Machu Picchu, Peru

The helplessness of the human newborn requires a new form of communication. The newborn monkey can communicate through purposeful actions.

The human newborn cannot. Instead, mothers have to guess their newborn’s wishes. They must understand the baby’s intentions in order to be able to provide the appropriate care.


While a newborn monkey is already an active member of its social group, the human newborn is helpless. The phenomena of mentalisation and intentionality are important to understand the mechanisms that work here and the abilities that need to be mastered by individuals.

Dunbar describes it as follows:

Nevertheless, primatologists have always assumed that there is such a thing as “social cognition” (a form of social recognition). This ability manifests itself in people as being able to put themselves in the mind of another person (a phenomenon known in psychological literature as “mentalising”.

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