An interesting little article about what you are doing when you are
doing nothing.
http://www.time.com/time/magazine/article/0,9171,1580364,00.html
What are you doing when you aren't doing anything at all? If you said
nothing, then you have just passed a test in logic and flunked a
test in neuroscience. When people perform mental tasks--adding
numbers, comparing shapes, identifying faces--different areas of their
brains become active, and brain scans show these active areas as
brightly colored squares on an otherwise dull gray background. But
researchers have recently discovered that when these areas of our
brains light up, other areas go dark. This dark network (which
comprises regions in the frontal, parietal and medial temporal lobes)
is off when we seem to be on, and on when we seem to be off. If you
climbed into an MRI machine and lay there quietly, waiting for
instructions from a technician, the dark network would be as active as
a beehive. But the moment your instructions arrived and your task
began, the bees would freeze and the network would fall silent. When
we appear to be doing nothing, we are clearly doing something. But
what?
The answer, it seems, is time travel.
The human body moves forward in time at the rate of one second per
second whether we like it or not. But the human mind can move through
time in any direction and at any speed it chooses. Our ability to
close our eyes and imagine the pleasures of Super Bowl Sunday or
remember the excesses of New Year's Eve is a fairly recent
evolutionary development, and our talent for doing this is
unparalleled in the animal kingdom. We are a race of time travelers,
unfettered by chronology and capable of visiting the future or
revisiting the past whenever we wish. If our neural time machines are
damaged by illness, age or accident, we may become trapped in the
present. Alzheimer's disease, for instance, specifically attacks the
dark network, stranding many of its victims in an endless now, unable
to remember their yesterdays or envision their tomorrows.
Why did evolution design our brains to go wandering in time? Perhaps
it's because an experience is a terrible thing to waste. Moving around
in the world exposes organisms to danger, so as a rule they should
have as few experiences as possible and learn as much from each as
they can. Although some of life's lessons are learned in the moment
(Don't touch a hot stove), others become apparent only after the
fact (Now I see why she was upset. I should have said something about
her new dress). Time travel allows us to pay for an experience once
and then have it again and again at no additional charge, learning new
lessons with each repetition. When we are busy having
experiences--herding children, signing checks, battling traffic--the
dark network is silent, but as soon as those experiences are over, the
network is awakened, and we begin moving across the landscape of our
history to see what we can learn--for free.
Animals learn by trial and error, and the smarter they are, the fewer
trials they need. Traveling backward buys us many trials for the price
of one, but traveling forward allows us to dispense with trials
entirely. Just as pilots practice flying in flight simulators, the
rest of us practice living in life simulators, and our ability to
simulate future courses of action and preview their consequences
enables us to learn from mistakes without making them. We don't need
to bake a liver cupcake to find out that it is a stunningly bad idea;
simply imagining it is punishment enough. The same is true for
insulting the boss and misplacing the children. We may not heed the
warnings that prospection provides, but at least we aren't surprised
when we wake up with a hangover or when our waists and our inseams
swap sizes. The dark network allows us to visit the future, but not
just any future. When we contemplate futures that don't include
us--Will the NASDAQ be up next week? Will Hillary run in 2008?--the
dark network is quiet. Only when we move ourselves through time does
it come alive.
Perhaps the most startling fact about the dark network isn't what it
does but how often it does it. Neuroscientists refer to it as the
brain's default mode, which is to say that we spend more of our time
away from the present than in it. People typically overestimate how
often they are in the moment because they rarely take notice when they
take leave. It is only when the environment demands our attention--a
dog barks, a child cries, a telephone rings--that our mental time
machines switch themselves off and deposit us with a bump in the here
and now. We stay just long enough to take a message and then we slip
off again to the land of Elsewhen, our dark networks awash in light.
xponent
Paging Dr Bob Maru
rob
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