Since I was young, I always associate the brain size with that person’s IQ. Scientists have debated the importance of brain size for centuries. Recently, researchers from University of Vienna suggests brain size only plays a small role in intelligence. In 1836, a German anatomist Friedrich Tiedemann raised a statement in the journal Philosophical Transactions, “There is undoubtedly a connection between the absolute size of the brain and the intellectual powers and functions of the mind.” Since then, debates over whether this theory right or wrong started. As technologies develop, advanced devices enable scientists to make more thorough  assessments toward brains.

The University of Vienna found an international team to study the relationship between brain size and IQ by  analysis 148 sample from 8,000 participants. Jakob Pietschnig from the Institute of Applied Psychology of the University of Vienna stated that “brain volume plays only a minor role in explaining IQ test performance in humans.” For example, the sperm whale has a much more larger brain than that of human, but the difference of IQ between sperm whale’s and human’s is obvious. Another example is, it’s known that men have larger brains than women, but there has no report about men have a more outstanding result in IQ tests. Contrarily, there exists a kind of growth development disorder called megalencephaly syndrome, which the brain achieve a size that is unusual large. Typically, people who suffer this disorder have a lower grades in IQ tests than normal people. Brain structure appear to be have a more strong relationship associate with IQ. The importance of brain structure becomes obvious when comparing different species.

Though the whole size of brain cannot indicate level of IQ, but sizes of some parts inside the brain do indicate something. Hippocampi (orange part) located in the both left and right sides of the brain, which is responsible for forming new memories.

When they are impaired, Alzheimer’s disease is likely to occur. The larger this part is, the more unlikely a person have a reduced risk of memory decline. A journal called Alzheimer’s Research and Therapy published an article about a study of examined 226 people for the relationship between the size of hippocampi and memory. This finding can predict potential developing dementia.

Is there a possibility that because some people are good at remembering things and improve their memories very often, so their hippocampi becomes larger? Just like muscles, some athletes use them more often, then they have a larger biceps. Is there a third variable that affect both the size of hippocampi and memory such as a hormone that circulates in the brain? These are my questions toward this topic that waited for further studies to answer.