▶ Your Answer :
The reading passage contends that the decrease in the average human brain size can be fully explained by three theories. On the other hand, the lecturer brings up several points that contradict this argument.
First, the speaker argues that it is unlikely that a change in human societies has lead to the decline in brain size. This is because although the modern society does not require people to be self-sufficient unlike the past, it necessities people to have the new type of intelligence such as social intelligence. This could have increased brain size, and thus it could not explain the diminished size of the brain. This casts doubt on the reading passage’ claim that an alteration in human societies is responsible for shrunk brain mass.
Second, according to the lecture, it is untrue that the decrease in body size has caused the brain to shrunk. This is supported by the fact that the rate of brain shrinking is faster than that of the body. If the reading’s statement were to be correct, the rate of diminishing between the two should have been the same. This counters the author’s point that as people became smaller, a huge brain became unnecessary.
The final point made by the lecture is that a diminishing visual cortex is not a primary reason. The reason is that the visual cortex occupies the smallest portion of the brain, and thus its change in size does not have much impact on the overall brain size. Moreover, other parts of the brain are also decreasing which indicates that the decrease in visual cortex is not the main reason for small brain size. This refutes the reading’s argument that diminishing visual cortex is a key factor in declining brain size. |