Intelligence used to provide a vital survival advantage, making smart genes more likely to be passed on to the next generation. But that era is long gone, thanks to today’s computers and other devices that override various human weaknesses. Today, evolution in general would seem to be, well…out of date.
But it turns out that cultural changes may be able to foster genetic changes that affect intelligence, while technological advances are ushering in a new era of brain evolution.
Bigger Brains Are Better—Up to a Point
For some 2 million years, our minds continued to expand. As the size increased, so did our intelligence. I guess that’s why aliens with superior intelligence in all those sci-fi movies have huge heads.
But have we finally hit a dead-end en route to a larger hat size? 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.
Brain Downsizing Trend?
According to John Hawks, an anthropologist at the University of Wisconsin, Madison, our brains have been reducing in size for the last 20,000 years. The average male brain has decreased from 1,500 cubic centimeters to 1,350, a loss about the size of a tennis ball. The female brain has shrunk by about the same percentage.
But this doesn’t mean our intelligence is on the decline. While the brain has been getting smaller, certain mutations to our DNA may have been increasing the efficiency of our minds. These mutations changed the nature of brain development and the function of neurotransmitters, which are chemicals that allow transfer of signals between nerve cells. What remains subject to debate is how those changes have affected our emotional framework and ability to reason.
Letting Culture Go to Our Heads
Of particular interest are changes in microcephalin and ASPM, two genes that regulate brain size. Based on studies conducted by University of Chicago researchers, a new variation of microcephalin first appeared about 37,000 years ago, while one for ASPM occurred only about 5,800 years ago. While these are hardly short spans of time, they are a mere blip in the 200,000-year reign of modern man (a k a Homo sapiens). Apparently, natural selection favored these changes, since the microcephalin variant is present in about 70% of humans today and the ASPM variant in about 30%.
Interestingly, each of these gene mutations occurred when human culture was leaping forward. Microcephalin was changing as art, music, religion, and advances in tool making appeared in the human timeline. The ASPM mutation had its roots in the establishment of Mesopotamia in 7000 BC, the oldest documented civilization.
As culture continues to change, our brains may keep evolving to keep pace. “Our environment and the skills we need to survive in it are changing faster than we ever imagined,” noted Dr. Bruce Lahn, a professor of human genetics at the University of Chicago, in Science Daily; “I would expect the human brain, which has done well by us so far, will continue to adapt to those changes.”
Of course, advances in intelligence that provide a survival advantage aren’t always good news for the human condition. “Just because these genes are still evolving, doesn’t necessarily mean they make you any smarter,” Dr. Lahn remarked. “We’ve evolved genes for selfishness, violence, cruelty—all of which are in place because they may make survival easier.”
Brain/Computer Interface May Take Intelligence to a New Level
In our high-tech era, the brain no longer has to work alone to advance to a higher level of functioning. Technology has already made its mark in working directly with the brain to correct defects. Lost hearing, for example, can be restored with implants that electronically stimulate the cochlear nerve (which conducts sensory stimuli from the hearing organ to the brain). Other devices are under development to reclaim function compromised by stroke or spinal cord injuries.
But what about implants that can enhance intelligence? A pathway to that startling advance is in sight, thanks to scientists such as Thomas Berger, a neural engineer at the University of Southern California, Los Angeles. Berger is developing a memory prosthesis capable of converting the electrical activity of a short-term memory in the brain to a digital signal that can then be sent to a computer. The digital information is then transformed in the computer and sent back to the brain, where it becomes sealed in as a long-term memory.
This process has tremendous implications for knowledge retention, skill building, and perhaps even treating memory loss in Alzheimer’s disease. While it has only been proven successful in rats and monkeys, humans may not be far behind.
Giving the Brain an “Out of Body” Experience
The next phase of human intelligence may be mind-blowing, according to predictions at the Global Futures 2045 International Congress—a meeting of thought leaders dedicated to optimizing the future of humanity. Congress presenter Ray Kurzweil, an inventor, futurist, and director of engineering at Google, claimed that a powerful alliance of brains and bytes may be just decades away. “Based on conservative estimates of the amount of computation you need to functionally simulate a human brain,” Kurzweil told the Huffington Post, “we’ll be able to expand the scope of our intelligence a billion-fold.” How might this be possible? By uploading the contents of our minds into a computer, bypassing the biological limitations on intelligence. Some theorists go so far as to say that consciousness itself may one day be preserved outside the body.
Those sci-fi aliens with XL brains are starting to seem very old-fashioned.
Find Out More
- Kathleen McAuliffe, “If Modern Humans Are So Smart, Why Are Our Brains Shrinking?” Discover
- Tanya Lewis, “’Mind Uploading & Digital Immortality May Be Reality by 2045, Futurists Say,” Huffington Post
- “University of Chicago Researchers Find Human Brain Still Evolving,” Science Daily