The Origin of Intelligence

The Origin of Intelligence

by : Professor Stephen Jay Gould 

       Many theories have been proposed as to why humans developed greater intelligence, going all the way back to Charles Darwin. According to one theory, the evolution of the human brain probably took place in stages, with the earliest phase initiated by climate change in Africa. As the weather cooled, the forests began to recede, forcing our ancestors onto the open plains and savannahs, where they were exposed to predators and the elements. To survive in this new, hostile environment, they were forced to hunt and walk upright, which freed up their hands and opposable thumbs to use tools. This in turn put a premium on a larger brain to coordinate tool making. According to this theory, ancient man did not simply make tools—“tools made man.

       Our ancestors did not suddenly pick up tools and become intelligent. It was the other way around. Those humans who picked up tools could survive in the grasslands, while those who did not gradually died off. The humans who then survived and thrived in the grasslands were those who, through mutations, became increasingly adept at tool making, which required an increasingly larger brain.

       Another theory places a premium on our social, collective nature. Humans can easily coordinate the behavior of over a hundred other individuals involved in hunting, farming, warring, and building, groups that are much larger than those found in other primates, which gave humans an advantage over other animals. It takes a larger brain, according to this theory, to be able to assess and control the behavior of so many individuals. (The flip side of this theory is that it took a larger brain to scheme, plot, deceive, and manipulate other intelligent beings in your tribe. Individuals who could understand the motives of others and then exploit them would have an advantage over those who could not. This is the Machiavellian theory of intelligence.)

          Another theory maintains that the development of language, which came later, helped accelerate the rise of intelligence. With language comes abstract thought and the ability to plan, organize society, create maps, etc. Humans have an extensive vocabulary unmatched by any other animal, with words numbering in the tens of thousands for an average person. With language, humans could coordinate and focus the activities of scores of individuals, as well as manipulate abstract concepts and ideas. Language meant you could manage “teams of people on a hunt, which is a great advantage when pursuing the woolly mammoth. It meant you could tell others where game was plentiful or where danger lurked.

       Yet another theory is “sexual selection,” the idea that females prefer to mate with intelligent males. In the animal kingdom, such as in a wolf pack, the alpha male holds the pack together by brute force. Any challenger to the alpha male has to be soundly beaten back by tooth and claw. But millions of years ago, as humans became gradually more intelligent, strength alone could not keep the tribe together. Anyone with cunning and intelligence could ambush, lie or cheat, or form factions within the tribe to take down the alpha male. Hence the new generation of alpha males would not necessarily be the strongest. Over time, the leader would become the most intelligent and cunning. This is probably the reason why females choose smart males (not necessarily nerdy smart, but “quarterback smart”). Sexual selection in turn accelerated our evolution to become intelligent. So in this case the engine that drove the expansion of our brain would be females who chose men who could strategize, become leaders of “the tribe, and outwit other males, which requires a large brain.

          These are just a few of the theories about the origin of intelligence, and each has its pros and cons. The common theme seems to be the ability to simulate the future. For example, the purpose of the leader is to choose the correct path for the tribe in the future. This means any leader has to understand the intentions of others in order to plan strategy for the future. Hence simulating the future was perhaps one of the driving forces behind the evolution of our large brain and intelligence. And the person who can best simulate the future is the one who can plot, scheme, read the minds of many of his fellow tribesmen, and win the arms race with his fellow man.

        Similarly, language allows you to simulate the future. Animals possess a rudimentary language, but it is mainly in the present tense. Their language may warn them of an immediate threat, such as a predator hiding among the trees. However, animal language apparently has no future or past tense. Animals do not conjugate their verbs. So perhaps the ability to express the past and future “tense was a key breakthrough in the development of intelligence.

         Dr. Daniel Gilbert, a psychologist at Harvard, writes, “For the first few hundred million years after their initial appearance on our planet, our brains were stuck in the permanent present, and most brains still are today. But not yours and not mine, because two or three million years ago our ancestors began a great escape from ” 

Can geniuses be learned ?

          This rekindles the question, Are geniuses made or born? ” “How does the nature/nurture debate solve the mystery of intelligence? Can an ordinary person become a genius ? Since brain cells are notoriously hard to grow, it was once thought that intelligence was fixed by the time we became young adults. But one thing is becoming increasingly clear with new brain research: the brain itself can change when it learns. Although brain cells are not being added in the cortex, the connections between neurons are changing every time a new task is learned.

         For example, scientists in 2011 analyzed the brains of London’s famous taxicab drivers, who have to laboriously memorize twenty-five thousand streets in the dizzying maze that makes up modern London. It takes three to four years to prepare for this arduous test, and only half the trainees pass.

           Scientists at University College London studied the brains of these drivers before they took the test, and then tested them again three to four years afterward. Those trainees who passed the test had a larger volume of gray matter than before, in an area called the posterior and the anterior hippocampus. The hippocampus, as we’ve seen, is where memories are processed. (Curiously, tests also showed that these “taxicab drivers scored less than normal on processing visual information, so perhaps there is a trade-off, a price to pay for learning this volume of information.)

        The human brain remains ‘plastic,’ even in adult life, allowing it to adapt when we learn new tasks,” says Eleanor Maguire of the Wellcome Trust, which funded the study. “This offers encouragement for adults who want to learn new skills later in life.

          Similarly, the brains of mice that have learned many tasks are slightly different from the brains of other mice that have not learned these tasks. It is not so much that the number of neurons has changed, but rather that the nature of the neural connections has been altered by the learning process. In other words, learning actually changes the structure of the brain.

         This raises the old adage “practice makes perfect.” Canadian psychologist Dr. Donald Hebb discovered an important fact about the wiring of the brain: the more we exercise certain skills, the more certain pathways in our brains become reinforced, so the task becomes easier. Unlike a digital computer, which is just as dumb today as it was yesterday, the brain is a learning machine with the “ability to rewire its neural pathways every time it learns something. This is a fundamental difference between a digital computer and the brain.This lesson applies not only to London taxicab drivers, but also to accomplished concert musicians as well. 

         According to psychologist Dr. K. Anders Ericsson and colleagues, who studied master violinists at Berlin’s elite Academy of Music, top concert violinists could easily rack up ten thousand hours of grueling practice by the time they were twenty years old, practicing more than thirty hours per week. By contrast, he found that students who were merely exceptional studied only eight thousand hours or fewer, and future music teachers practiced only a total of four thousand hours. Neurologist Daniel Levitin says, “The emerging picture from such studies is that ten thousand hours of practice is required to achieve the level of mastery associated with being a world-class expert—in anything.… In study after study, of composers, basketball players, fiction writers, ice skaters, concert pianists, chess players, master criminals, and what have you, this number comes up again and again.” Malcolm Gladwell, writing in the book Outliers, calls this the “10,000-hour rule.