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ultitasking, when it comes to
paying attention, is a myth.
The brain naturally focuses on
concepts sequentially, one at
a time. At first that might sound confusing; at
one level the brain does multitask. You can walk
and talk at the same time. Your brain controls
your heartbeat while you read a book. Pianists
can play a piece with left hand and right hand
simultaneously. Surely this is multitasking. But I am
talking about the brain’s ability to pay attention. It
is the resource you forcibly deploy while trying to
listen to a boring lecture at school. It is the activity
that collapses as your brain wanders during a
tedious presentation at work. This attentional
ability is not capable of multitasking.
Recently, I agreed to help the high-school son of
a friend of mine with some homework, and I don’t
think I will ever forget the experience. Eric had been
working for about a half-hour on his laptop when I
was ushered to his room. An iPod was dangling
from his neck, the earbuds cranking out Tom Petty,
Bob Dylan, and Green Day as his left hand reflexively
tapped the backbeat. The laptop had at least 11
windows open, including two IM screens carrying
simultaneous conversations with MySpace friends.
Another window was busy downloading an image
from Google. The window behind it had the results
of some graphic he was altering for MySpace friend
No. 2, and the one behind that held an old Pong
game paused mid-ping.
Buried in the middle of this activity was a word-
processing program holding the contents of the
paper for which I was to provide assistance. “The
music helps me concentrate,” Eric declared,
taking a call on his cell phone. “I normally do
everything at school, but I’m stuck. Thanks
for coming.” Stuck indeed. Eric would make
progress on a sentence or two, then tap out a
MySpace message, then see if the download
was finished, then return to his paper. Clearly,
Eric wasn’t concentrating on his paper. Sound
like someone you know?
To put it bluntly, research shows that we can’t
multitask. We are biologically incapable of
processing attention-rich inputs simultaneously.
Eric and the rest of us must jump from one
thing to the next. To understand this remarkable
conclusion, we must delve a little deeper into the
third of Posner’s trinity: the Executive Network.
Let’s look at what Eric’s Executive Network is
doing as he works on his paper and then gets
interrupted by a “You’ve got mail!” prompt from
his girlfriend, Emily.
step 1:
shift alert
To write the paper from a cold start, blood quickly
rushes to the anterior prefrontal cortex in Eric’s
head. This area of the brain, part of the Executive
Network, works just like a switchboard, alerting
the brain that it’s about to shift attention.
step 2:
rule activation for task #1
Embedded in the alert is a two-part message,
electricity sent crackling throughout Eric’s brain.
The first part is a search query to find the neurons
capable of executing the paper-writing task. The
second part encodes a command that will rouse
the neurons, once discovered. This process is called
“rule activation,” and it takes several tenths of a
second to accomplish. Eric begins to write his paper.
step 3:
disengagement
While he’s typing, Eric’s sensory systems picks
up the email alert from his girlfriend. Because
the rules for writing a paper are different from
the rules for writing to Emily, Eric’s brain must
disengage from the paper-writing rules before
he can respond. This occurs. The switchboard is
consulted, alerting the brain that another shift in
attention is about to happen.
step 4:
rule activation for task #2
Another two-part message seeking the rule-
activation protocols for emailing Emily is now
deployed. As before, the first is a command to
find the writing-Emily rules, and the second is the
activation command. Now Eric can pour his heart
out to his sweetheart. As before, it takes several
tenths of a second simply to perform the switch.
Incredibly, these four steps must occur in sequence
every time Eric switches from one task to another.
It is time-consuming. And it is sequential. That’s
Multitasking Myth
THE BRAIN
CANNOT MULTITASK
By Dr. John Medina
