However having a large brain involves costs-larger brains use a higher proportion of an individual energy. Humans use 22% of their energy sustaining the brain compared with only 8% of chimpanzees.
According to Kliniwoska, if brain size equated to intelligence than the whale which has an average brain weight of 9kg compared to the average human brain weight of 1.3kg, would be 5 times cleverer than humans. Brain is needed to control bodily functions, so a large body necessitates a large brain. Whales weigh on average 37 tonnes and humans 0.07.Therefore, having a large brain does not correlate with higher levels of intelligent. This suggests that, if we assume that humans are more intelligence, we need to consider the EQ size (the weight of the brain relative to the body.
McDaniel conducted a meta-analysis providing support for the idea that intelligent people have larger brains. He used 1530 people from 37 samples and found a positive correlation between brain size and intelligence.
However, Sassaman and Zartler (1982) studied children with abnormality small brains: 40% were not retarded, suggesting that brain size does not reflect intelligence. This can also reflect animals, as crows show intelligent tool use, planning and cognitive flexibility, but have small brains.
Evolutionary explanations of human intelligence are reductionist, as they reduce complex behaviours to one explanation of adaptiveness and therefore do not consider other important factors, like cultural influences.
Also, Explanations of human intelligence based on evolutionary theory can be argued to be deterministic in that they see intelligence as caused by past environments coded into humans in the form of innate genetic structures. Therefore,