Through the ages our brains had to evolve to meet survival needs, but is it an ongoing process or have we obtained our greatest mental capacity? As time went on our brains expanded in size for a period of two million years, however that may be changing. According to an article called The Future of Intelligence, the author states “Continuing expansion of our command center is challenged by its major nutritional requirements: The brain consumes about 20% of the “basal calories” we burn each day—those that are metabolized when the body is at rest.  Enlargement beyond a certain point might place too great a demand on metabolic resources to justify it for the body as a whole.” John Hawks, who is an anthropologist at the University of Wisconsin, Madison, seems to agree that the brain can only evolve to a fault. He explains that our brains are actually decreasing in size and have been doing so for a long time, specifically looking at the male brain, which has gone from 1,500 cubic centimeters to 1,350 cubic centimeters. He found this out by reviewing archaeological data on brains that come from China, Europe, Australia, and South Africa. The female brain is closely matched to the male’s in size reduction as well. Does this mean we’re getting dumber? Not at all. In fact, thanks to DNA undergoing mutations have made our today brains more intelligent then before. We know this because neurotransmitters are still firing between nerve cells.

There are two genes that aid in the efforts to regulate the size of the brain called ASPM and microcephalin. Researchers at the University of Chicago discovered a modified version of  microcephalin that was spotted an estimated 37,000 years ago, whereas a modification to ASPM was discovered 5,800 years ago. Homo sapiens have been around for about 200,000 years so if that is to be considered, these genes have held strong through the years. To be exact, 70% of humans have this latest microcephalin gene and 30% of people have the newest version of the ASPM gene. Dr. Bruce Lahn, a professor of human genetics, led the study to reach this conclusion.  What Lahn and his team did was figure out the DNA structure of the two genes in multiple groups of primates and compared them to humans. Since specific groups had a greater presence of these genes this led to the presumption that they were needed for some purpose and carried through in the process of natural selection. To see if humans still had these gene variations occurring in them, the team randomly selected 90 individuals of a variety of ethnic backgrounds. By looking at a chimpanzee, which was part of the primate group and tracing it’s DNA make up, they were able to find the same alterations or polymorphisms in the genes to link the human to the primate.

While Hawk and Lahn have an optimistic approach to the future of human evolution, others have great concern. In a 2014 study, published in the American Journal of Physical Anthropology conducted by Chinese researchers found that a Cro Magnon man, an earlier version of the Homo sapien, had a brain that was much larger than the size that humans have today. Now, this was already known based off of the other studies conducted by Hawk and Lahn, however their fears lied in how fast our brains are shrinking in comparison to our bodies. This is known as the Encephalization Quotient (EQ). If our brains were to shrink faster than our bodies, that could be problematic. On the contrary, the majority of scientists see this study as an isolated one and agree that a greater increase in brain size isn’t necessarily a good thing. Brian Hare, who is an anthropologist out of Duke University, explains that “the decrease in brain size is actually an evolutionary advantage because it could indicate we’re evolving into a less aggressive animal. For example, the common chimpanzees have bigger brains than bonobos, but they are less likely to resolve issues through teamwork because they’re more aggressive.”

So, what does the future hold? Thomas Berger, a neural engineer out of the University of Southern California, Los Angeles is working on a memory prosthesis, which would transmit electrical activity of a short-term memory in the brain to a digital signal that will be sent to a computer. When the information is received by the computer, it would then send the feedback back to the brain, where it can be permanently stored in the brain. Can’t wait to see how that turns out!
 

Sources: 

http://www.ancient-origins.net/news-evolution-human-origins/scientists-are-alarmed-shrinking-human-brain-001446

http://www.hhmi.org/news/human-brain-still-evolving

http://www.livescience.com/7971-humans-evolving-brains-shrink.html

http://www.rewireme.com/neuroscience/the-future-of-intelligence-is-the-human-brain-still-evolving/

http://www.supremebrainnutrition.com