With the 2010 political season well upon us, think of this: During the famous Illinois senate election campaign of 1858 between Abraham Lincoln and Stephen Douglas, each of the seven debates that were held lasted three or more hours. And they were well attended, with audiences paying rapt attention.

How quaint.

By comparison, it’s hard to imagine today’s public paying attention to a political candidate for more than 20 minutes. Charting the steady drop-off in viewership during the course of presidential State of the Union addresses proves the point.

In fact, Prof. Bradley Vander Zanden of the University of Tennessee maintains that the average attention span of an adult today is just that: 20 minutes.

And if you’re thinking that attention spans are getting shorter, you’re not wrong. Moreover, the Internet is contributing to this overall trend, because the average attention span online only is three to five minutes.

The phenomenon of multi-tasking is ubiquitous, with people surfing the Internet while watching television … cyber-chatting with friends while listening to music … checking e-mail inboxes while cooking a meal. Colleen Rush, an executive vice president at MTV Networks, reports, “Our research showed that people somehow managed to shoe-horn 31 hours of activity into a 24-hour day. That’s from being able to do two things at once.”

Researchers now think that technology is having subtle effects on the way our brains actually work. Nora Volkow, a leading brain scientist who is also director of the National Institute on Drug Abuse (part of NIH), contends that digital stimulation is similar to our need for food: essential for our being but counterproductive in excess.

Volkow and others believe that our ability to focus is being undermined by information overload, much of it coming in short bursts. These bursts of information play to a primeval impulse to respond immediately. Neurologically, the stimulation provokes excitement in the form of a dopamine dosage that experts say can be addictive. In its absence, people feel bored.

I bet you can think of several of your business colleagues who exhibit just those sorts of traits.

In the same vein, heavy multitasking can actually make it more difficult to discern and shut out irrelevant information. More ominously, some experts maintain that the stimulative urges of multi-tasking actually lessen our ability to engage in deeper analytical thought and creative musing. Ouch.

Food for thought, indeed.