The Brain Evolution Essay

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The emergence of human brain evolution can be chased back to the Carboniferous Period 365 million years ago. Our brain first consisted of the most primitive part, hypothalamus only. Then it had evolved to gain another limbic system around 200 million years ago and finally reached it’s final stage of evolution, the brain cortex around 2.58 million years to 12,000 million years ago. Our human brain size has increased threefold since the age of Australopithecus. There are many possible theories and hypothesises which can explain this enlargement of brain size. Among the theories, the most powerful reason or factor that caused such a dramatic evolution of human brain is the social brain hypothesis. There is a saying that the real challenge in human environment throughout history affected the evolution of the intellect was the necessity to deal with one another in social circumstances. Social circumstances stands for interactions between one another. Evidence has shown that the neocortex ratio has a positive correlation with the mean group size, suggesting the neocortex ratio of the people in the bigger clique size is higher that that of smaller clique size. There is also a statistic showing the cranium capacity is 0.79 correlated to the population density. The brain was believed to evolve as the same time with the human language. Ever since language and speeches are developed to enhance social interactions, our human brain is further developed. As interactions were more frequent as soon as language or even sign languages were emerged, there were even higher frequency in social interactions within a clique. These interactions includes grooming others, male’s strategies to attract female, social play, tactical deception, etc… There is also research showing the larger than brain is, the more intellect one is. Or more of less related to one’s IQ. From this saying and
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