Recent years have brought advances in technology that have been revolutionary, but are they also evolutionary?
Whether technology will have an impact on the evolution of the human species is a controversial question, but there already are signs that we are using our brains differently today than people did just a generation ago.
Quick, how many telephone numbers have you committed to memory? Probably not as many as you did before you started storing contacts in your cell phone. Do you use your brain, or a calculator, to answer math problems? Why memorize facts when all the world's information is as close as the nearest Internet connection?
Today's technological advances are, of course, a mere blip on the human evolutionary timeline, but there are certainly precedents for technology playing a role in previous episodes of human evolution, such as breakthroughs in the creation and use of hunting tools or the development of agriculture tens of thousands of years ago.
William Halal, a professor of science, technology and innovation at George Washington University and author of the forthcoming book "Technology's Promise," said he sees the coming decades as a time of major change for technology and the human condition.
By 2020, Halal predicts, artificial intelligence, robotics and other technologies will advance to the point where they take over many of the mundane tasks humans now perform both physically and mentally. That, he said, is good because it will free up the world's human resources to deal with more pressing global concerns.
"All of the routine things we currently preoccupy ourselves with are going to disappear and people are going to do what? We will move up another notch in the level of evolution," he said.
"Humans are going to move on to higher-order functions that are going to be needed to address these enormous challenges that will face the world," he said, citing global issues such as international conflict, energy depletion, climate change, environmental degradation and weapons of mass destruction.
"This will be a very promising period in the history of man," Halal said.
Patrick Tucker, director of communications for the World Future Society and senior editor of the Futurist magazine, said new technologies that enable humans to avoid mundane mental and physical tasks could lead to generations of people who are less physically able.
There already is evidence humans are doing less physically. Not long ago, for example, if you were seeking the answer to a complicated question, you had to go to the library, or grab a book from a shelf, physically open it and look for the answer. Now, you just type your query into an Internet search engine such as Google. Soon, you'll ask your computer the question verbally, eliminating even the use of your fingers to access information.
"We are the first humans to outsource jobs to technology, to automate that which is labor intensive or mentally tedious," said Tucker. "In the 21st century, this may result in people that are by and large less capable than we are today. Whether or not we seize all of those opportunities depends on how we mature in the coming decades."
So if today's humans are devoting fewer resources to things like rote memorization of phone numbers or mathematical calculations, where is all that brain power going? Maybe it's going to develop more technology, says Peter Rojas, writer and creator of the tech review site Engadget, who is devoting his energies to music publishing as CEO of rcrdlbl.com.
"People who have grown up in the digital era have an innate sense of what information is worth internalizing and what is not," Rojas said. "Not that it is not valuable to know things, but being able to access and discover and find information is in some ways more important."
"There are a lot of other important things we use our brains for that aren't memorization, like learning to think abstractly and creatively to develop new stuff," he said.
But those who look at things in an evolutionary context say modern technological changes are not likely to significantly affect the human species because while technology might change human behavior -- the way we think or other aspects of our humanity -- it also can supply solutions that prevent our genes from dealing with our problems.
John Hawks, a professor of anthropology at the University of Wisconsin, explained that evolution is all about natural selection and genes, and humans have evolved because superior genes led to the procreation and survival of those with the most robust genetic makeup.
Today, things such as diminished eyesight because of overexposure to computer screens for example, can easily be corrected with glasses or surgery and therefore won't affect the human gene pool.
"Sitting in front of a computer all day, you are using your eyes differently than if you're hunting all day in the wild, but there is not a genetic susceptibility there. Our population is not going to evolve because of these things," Hawks said.
"There are all kinds of technologies to deal with things like diseases, obesity, addiction. There are technologies that are there to address changes in humans that may be brought on by the use of technology. Our genes in some sense don't have to respond."
Still, Stanley Ambrose, a professor of anthropology at the University of Illinois, at least allows for the possibility that technology could be having an impact on human evolution. But like all evolutionary ideas, the question will not be answered over mere generations, but over thousands of years.
Take for example the human thumb, which throughout history has been used in opposition to fingers for grasping things. Today, the thumb has taken on new prominence among digits as it is used more and more to operate handheld communication devices.
"There may be some genetically based extra neural connection that could allow me to text-message faster," Ambrose said. "Faster text-messaging could get me a better job and allow me to have more kids to inherit my thumb gene. That would be evolving."
He added, however, if there were a text-messaging gene, it might already have been present in humans, but stayed dormant until a use for it came about.
"People could have been evolving a better text-messaging thumb gene for 100,000 years, but it didn't do any good until BlackBerrys came around. It could be a capacity that some had that suddenly became advantageous," Ambrose said.