Ask A Scientist

Why are we so much smarter than anything else?

Asked by: Billy Robinson
School: Owego Elementary School
Grade: 6
Teacher: Mr. Scott Snyder
Hobbies/Interests: Playing with my chickens and cats
Career Interest: N/A

Answer from Michael A. Little.

Distinguished professor of anthropology, Binghamto

We humans are the smartest animals on the planet because we have the largest and most complex brains in proportion to the size of our bodies. Other animals, such as elephants, have bigger brains than humans and are also very intelligent, but they are not even close to humans in how they are able to think. Probably the smartest animals next to humans are the Chimpanzees (our closest relatives) and other large apes (Gorillas and Orangutans), but their brain sizes are less than half of our brain sizes. By about 7 or 8 years old our brains are almost the size of adults, which have a volume of about 1,300 cubic centimeters or nearly a quart and a half. Some people have very large brains (about two quarts) and others have smaller brains (about one quart), but in people, the overall size does not seem to influence intelligence. For example, women have smaller brains than men because they have smaller bodies, on average, but they are no less smart for their smaller brains than are men. In addition to its large size, our brain is extraordinarily complex and contains about 100 billion nerve cells or neurons. These neurons are quite diverse and have the property of receiving and transmitting information. Each cell is connected to many other cells which makes this network able to exchange information widely and very rapidly. The most advanced part of our brain is the cerebral cortex, which is this complexly folded outer part of the brain that may remind you a little of cauliflower. This is packed with neurons that enable us to think in very complicated ways and to solve intricate problems. Another very important ability (perhaps the most important ability) that humans have is language, or the ability to speak. We seem to have a genetic ability to learn a language when we are young, and that ability is built directly into our brain's construction. One of the questions that scientists ask about our brain is how did we come to be so smart? We do not have all the answers, but we have some of them. For example, we know that our brains have evolved over the past three or four million years from a size close to the present-day apes in our early ancestors (Australopithecus) to about two-thirds of our present brain size about two million years ago (in early Homo habilis). Over the next two million years, our brain reached its present size, but it is probably only within the last 100,000 or 50,000 years that our brain became as complex and smart as it is now. Scientists are not absolutely sure why we became so smart, except that being smart helps us to get food and survive, so this ability is very useful. It also makes life very interesting if we use our brains a great deal. Like our muscles, exercising our brains helps them to stay healthy and even makes them smarter!

Last Updated: 9/18/13