This is a profound teaching quote not because it implies the teacher has an unending fountain of knowledge to share with a student, but because he is able to empathize with the experience of being an authentic student. 

It is one thing to "get work done" while distracted (grading papers, reading articles, etc), however it is a profoundly different matter to learn something new and difficult with even superficial distractions.  This summer, I myself spent time revisiting some higher level math.  This material required focus, multiple pass throughs, and drill/kill exercises to truly drive home the point and "own" the concept/knowledge (i.e.: The highest level of synthesis is to be able to recognize when/where to apply it to real life situations in the future).  When needing this 100% focus, I realized how many looming distractions I have at home that interrupt deep thinking.  The productivity of superficial multi-tasking has been debunked.

It made me reflect on my undergraduate experiences in Mathematics and Computer Science, which routinely required deep focus and persistence.  Ironically, my 1990 college experience had more in common with college in 1940 than 2010.  As recently as 1990, we lived in army style barracks with cinderblock walls & few amenities:  No TV, no cell phone/texting, no landline phone (payphone at end of hallway), no computer/IM/WWW/Facebook (just a PC lab on campus to type papers).  With merely a stereo in an otherwise spartan bedroom, it was *still* easy to get distracted in your dorm room (friends, noise, bed, music, etc) Therefore, we quickly learned that you did not do homework in your room.  I tackled the rigorous coursework in a remote, desolate, wooden "cubicle" in the library basement.  Here, I could get into "deep zone" study for hours on end, with zero interference or stimuli to knock me out of the zone (See diagram below)

As a teacher, I have told my students to find a quiet place at home to study.  However, I now realize that I can't stress this point enough.  Taken to extremes, you need to be in an empty prison cell with a desk, pen, paper, & assignment.  For example, well-intentioned parents might equip their child’s room with a computer as a learning resource.  For a subject like Math, I feel that if there is even a PC present in the bedroom, or if the cell phone in your pocket is merely on... you are opening to door for interruptions and battling potential temptations  Odds are, you will NOT enter (or remain in) the "flow/zone".   A student must keep this in mind when establishing his study area in high school, college, and beyond.

• Cell Phone OFF:  No texting or phone calls
  
• Computer OFF: No email, Facebook, IM, internet, or games.

Diagrams adapted from: Orientation to College Learning

Computers at Home:
Educational Hope vs. Teenage Reality

• The Duke paper reports that the negative effect on test scores was not universal, but was largely confined to lower-income households, in which, the authors hypothesized, parental supervision might be spottier, giving students greater opportunity to use the computer for entertainment unrelated to homework and reducing the amount of time spent studying.

• Poor retention:  "...when forced to multitask, the overloaded brain shifts its processing from the hippocampus (responsible for memory) to the striatum (responsible for rote tasks), making it hard to learn a task or even recall what you’ve been doing once you’re done."

• He sees our distraction as a full-blown epidemic—a cognitive plague that has the potential to wipe out an entire generation of focused and productive thought. He compares it, in fact, to smoking. “People aren’t aware what’s happening to their mental processes,” he says, “in the same way that people years ago couldn’t look into their lungs and see the residual deposits.”

•  If John Lennon had a BlackBerry, do you think he would have done everything he did with the Beatles in less than ten years?”

Excerpts from Rapt: Attention and the Focused Life

• Learning tennis is best done between the ages of 8 and 15.  The longer you delay, the harder it will be, and your ability to play will suffer.  This principle applies to all sorts of skills, both physical and mental, including the ability to concentrate, direct your focus at will, manage your time.  Kids also need to work at developing the capacity for the concentrated, sustained attention required to succeed in many endeavors. 

• The young can get away with IM'ing while playing a computer game, but there's a risk.  If you grow up assuming that you can pay attention to several things at once, you may not realize that the way you process such things is superficial at best.  When you're finally forced to confront intellectually demanding situations in high school or college, you may find you've traded depth of knowledge for breadth, and stunted your capacity for serious thought.

• Studies show that through practice, you can expand your capacity to focus.

• Where big breakthroughs are concerned, getting to "That's it!!" requires not only the intense focus and explicit learning ...but also plenty of (non-conscious) incubation, mind wandering, and implicit learning.

• Science has determined that multitasking, for most practical purposes, is a myth.  Focusing on 2 demanding activities simultaneously is a skill that requires months of drilling to acquire, and, even then, is confined to just those two tasks!

• You may think you're multitasking, but what you're really doing is switching back and forth between two activities.  The extra effort involved actually makes you less productive.  Your overall performance will be inefficient, error prone, and more time consuming than if you had done one thing at a time.  If your train of thought is interrupted even for a second, you have to go back and say "Where was I?"  There are startup costs each time as you reload everything into memory, and people aren't as good at is as they think they are.

• When you focus on a demanding task, your brain's hippocampus, which is important to memory, is in charge.  However, if you try to work while distracted by instant messaging, or the like, the Striatum, which is involved in rote activities takes over.  As a result, even if you get the job done, your recollection of it will be more fragmented, less adaptable, and harder to retrieve than it would be had you given it your undivided attention.

To Deal With Obsession, Some Defriend Facebook