Re: [Phys-L] multitasking

["John Clement" <clement@hal-pc.org>]

Everyone agrees that there are things that are completely asyncronous in the
brain and body.  The NPR story was just considering cognitive processes, and
as such was accurate.  When people talk about multitasking they are always
considering dividing their attention between a number of tasks.  And that is
what most of this discussion revolved around.  With respect to the brain
there are cognitive tasks and automatic tasks, and automatic tasks are not
considered when looking at multitasking.  Nobody would consider chewing gum,
walking, and talking as multitasking.

The NPR report used a simple example of multitasking, but what about a more
complex one.  For example doing a physics problem can involve a number of
things which have to be considered.  If you leave it to talk on the phone,
and then come back it, some things get lost, so you may have to go back and
retrace what you have already done.  This adds considerably to the cognitive
overhead.  It is no just a simple switching of attention.  Computers have a
fairly fixed time to switch tasks and store/restore registers on the stack.
But people have a more complex situation.  Remember that you can only keep
about 9 things in working memory at a time, and many students may go as low
as 4 things.

Sometimes multitasking can impinge on automatic tasks.  If you know a simple
repetitive dance really well, you can talk with others in the line.  But
sometimes that messes up your steps probably because there is a cognitive
element still in play.  Also when something really big and important is
going on your brain shuts off other signals.  Background music is not
noticed or it interferes whcn you are trying to do physics problems.  The
ADD individual has difficulty with shutting off distractions.  I suspect
that the theoretical physicist tends to do this very well.  Then there are
combinations of tasks that are helpful.  Doodling has been found to happen
while people are really paying attention.  It may be helpful.

So in general multitasking has been found to deteriorate performance
overall.  But there are situations where it is necessary for performance,
but that does not mean that performance on individual tasks is not
suffering.  It most probably is degraded.  There is a difference between
driving in traffic and flying, which probably goes to the heart of the
reason why phone use should be banned on the highways.  I doubt that cell
phone chit-chat is approved of for pilots.  I am perfectly OK with banning
my cell phone use to prevent the lady in the SUV from killing me while she
is talking on the phone.  The alternative might be to make killing someone
accidentally while using a cell phone a felony equivalent to manslaughter.
Notice that we make our stories to fit our preconceptions, and we downgrade
the dangerous actions accordingly.  So far there have been no studies that
show a zero effect of cell phones on driving ability.  It may be that there
are some individuals for whom this is true, but they have not been
identified.  So the weight of the evidence is against cell phone use while
driving.

John M. Clement
Houston, TX




> My point for today is that the vast majority of human thought is
> done in parallel.  Note the contrast:
>  *) the parts that are easy to talk about -- namely the parts 
>   involving conscious attention -- are mostly serial, but
>  *) the other 99.999%  -- including perception, learning, and
>   recall -- is massively parallel.
>
> Let's be clear:  In this thread, everything that has been said
> (by me and others) about "division of attention" is misleading.
> Even the parts that were 100% true and useful were misleading,
> because they missed the most important point:  Even though 
> /attention/ is in some sense serial, most brain function is 
> massively parallel.
>
>
> All in all, I am astonished and horrified when I see things like this:
>   http://www.npr.org/templates/story/story.php?storyId=95256794
>
> which revolves around the assertion that:
> > researchers say [multitasking is] still a myth - and they 
> have the data to prove it.