Table of contents:
Do you know what size your brain is? Some say that someone with a larger brain volume is definitely intelligent. So, what exactly affects the size of the human brain? The following is the review.
Facts about brain size you need to know
The human brain is different. The brain in men is larger than that of women. The human brain weighs an average of 2.7 kilograms or 1,200 grams, which is about 2 percent of your body weight. Men have about 100 g more than women after accounting for the difference in total body weight. Then, what affects the size of the human brain? This is the answer.
1. Residence
The location where humans live on earth can affect the size of the brain. If you live further away from the equator, your brain will be bigger because you have to adapt to low light conditions, especially the part of the brain that regulates visual abilities.
Likewise, humans who live close to the equator, the sun that shines throughout the year provides sufficient lighting so that the size of the brain tends not to enlarge. The average skull size of tropical humans is smaller than that of polar humans.
However, various studies have shown that brain size is not always related to intelligence level. Sometimes a smaller brain works more efficiently and so the intelligence is higher.
According to a recent study by Eiluned Pearce of the University of Oxford, the difference in brain size and skull bone is most pronounced at the eye opening (eye socket). This reinforces the notion that lighting factors most influence differences in brain size.
According to Pearce, the farther from the equator, the less light so humans evolved to form bigger eyes. Larger eyes mean that more visual information is received, so the brain is enlarged to be able to process more information.
Pearce concluded this after examining 55 ancient skulls from various periods and burial sites around the world. From measuring the skull bones and eye holes, he found that Scandinavians have the largest brains.
People living in the tropics have, on average, a small brain size, which is about 22 milliliters. This size is slightly smaller than the size of the average British person living in cold climates, which is 26 milliliters.
2. Specific genes
According to scientists, a person's brain size is influenced by a specific gene. This research was conducted by a medical team from the University of California Los Angeles, according to research team leader Paul Thompson, this study found evidence of a gene component that affects the brain.
The research data were obtained from brain scan samples and genetic data belonging to 21,151 people worldwide. The researchers found a specific gene link to variations in brain size, which shrinks naturally with age.
Decreased brain volume usually indicates a medical condition such as Alzheimer's disease, depression, and schizophrenia. This was revealed by scientists in the journal Nature Genetic.
For example, the hippocampus is a part of the brain associated with memory formation and the organization of brain work. The gene sequence rs7294919, on chromosome 12, is associated with this variation in the volume of the hippocampus. People with certain genetic variants in that region, called the T-allele, have a smaller hippocampal volume.
