The evolution of the human brain compared to other animals, especially primates, is still a mystery in constant research. Sparking much debate since the English naturalist Charles Darwin presented his theory of evolution to the world in 1859.
One of the most important hypotheses trying to explain this difference is the Machiavellian intelligence theory, which relates the evolution and development of the brain with the level of social development of each species.
What is the theory of Machiavellian intelligence?
Unlike other animals, humans have experienced immeasurably superior brain development, with the cognitive and behavioral consequences that this entails. Even compared to primates, the human brain is considerably larger and more complex.
Although it is not yet possible to establish with complete certainty what is the cause of these abysmal differences in terms of brain development, there are many theories which attempt to explain this phenomenon which gave “homo sapiens “the ability to develop a much more complex mind. .
Some of them suggest that brain development is a response to the ability to adapt to changes or alterations in the environment. According to these hypotheses, subjects with more adaptability and who were able to overcome and survive the adversities of the environment, such as environmental or weather conditions, succeeded in propagating their genes, leading to progressive brain development.
However, there is another theory that is much more supported by the scientific community: the Machiavellian intelligence theory. Also known as the Social Brain Theory, this hypothesis postulates that the most important factor in brain development is social competition.
Generally speaking, this means that people with more social skills were more likely to survive. Specifically, those skills considered Machiavellian refer to social behaviors such as the ability to lie, contempt and insight. In other words, that is to say the smartest topics with the most social skills they achieved much greater social and reproductive success.
How did this idea come about?
In the research paper “Social Behavior and Evolution of Primates” published in 1953 by researchers MRA Chance and AP Mead, it was first suggested that in social interaction, understood as part of a competitive environment to access a status within a social structureThe key to understanding brain development in hominid primates could be found.
Later, already in 1982, the Dutch researcher specializing in psychology, primatology and ethology Francis de Waal, introduced the concept of Machiavellian intelligence in his work Political Chimpanzee, in which he describes the social and political behavior of chimpanzees.
However, it was not until 1988 that the Machiavellian intelligence theory as such was developed. Through the experiment linking the concepts of brain and social cognition and Machiavellian intelligence, psychologists Richard W. Byrne and Andrew Whiten, researchers at the University of St. Andrews in Scotland, are conducting a collection of research published under the name “Machiavellian intelligence: social experience and the evolution of the intellect in apes, apes and humans”.
In this work, researchers present the assumptions of Machiavellian intelligence, which attempts to convey the idea that the simple need to be more insightful and cunning than other individuals generates an evolutionary dynamic in which Machiavellian intelligence in the form the use of social cognition skills, would result in social and reproductive benefit.
Brain development and social intelligence
Although at first glance it may be difficult to associate the level of intelligence or development of the brain with a phenomenon of a social nature, the truth is that the Machiavellian intelligence hypothesis is based on neuroanatomical evidence.
According to this theory, cognitive demands and demands due to an increase in social interactions, which in turn arise from the gradual increase in the number of individuals in a society, have led to an increase in the size of the neocortex, as well as of its complexity.
From the point of view of the Machiavellian intelligence hypothesis, the increase in complexity and size of the neocortex depends on the variability of behaviors that the subject can achieve in interaction with his society. This specification is particularly relevant because it explains the differences in neocortex development between primates and humans compared to other animal species.
In addition, many works and studies support the idea that the dimensions of the neocortex increase as the size of the social group increases. Moreover, in the specific case of primates, the size of the amygdala, an organ traditionally linked to emotional responses, also increases as the size of the social group increases.
This is because for integration and social success the correct development of modulation and emotional regulation skills is necessary, hence the consequent increase in the size of the amygdala.
The study of Gavrilets and Vose
In order to test this hypothesis, researchers at the University of Tennessee, USA, S. Gavrilets and A. Vose conducted a study in which, by designing a mathematical model, the development of the brain of people based on the theory of Machiavellian intelligence.
Therefore, the researchers took into account the genes responsible for learning social skills. In conclusion, the cognitive abilities of our ancestors increased significantly over only 10,000 or 20,000 generations, a very short period of time given the history of mankind.
This study describes brain and cognitive development in three different phases that have occurred throughout human history:
- First phase: the social strategies created were not transmitted from individual to individual.
- Second level: known as the “cognitive explosion” phase, In it, a climax in the transmission of knowledge and social skills was pronounced. It was the time of the greatest brain development.
- Third phase: called “saturation” phase. Due to the enormous expenditure of energy involved in maintaining a constantly growing brain, its growth stopped, remaining as we know it today.
It should be clarified that the authors themselves report that their results do not necessarily prove the hypothesis of the Machiavellian intelligence theory, but that the mechanisms or phenomena that produced this growth may coincide with the historical temporal moment in which the assumption that they happened.