Your Visuospatial Sketchpad

1. Your Visuospatial Sketchpad. Consider this a drawing pad in
which you place visual images as you see something or where you
sketch the images you create in your mind when someone tells you
something.20 For example, as you watch a TV show or movie, the
series of images you see get placed on this sketchpad, and some of
the most memorable will move on to your long-term memory. You
won’t remember every detail, since there are thousands of such images
zipping by in a minute. But your memory for these images will
string them together—and as you improve your memory for visual
details, you will be able to notice and remember more.
This is also the section of your memory that works on turning
what you are hearing or thinking about into visual images. For example,
as you read or hear a story, this is where you create images
for what you are listening to, so it becomes like a movie in your
mind. Or suppose you are trying to work out a math problem in your
mind. This is where you would see the numbers appear, such as if
you are trying to multiply 24 33 and don’t already have a multiplication
table for that problem in your mind. You would see the individual
rows as you multiply and then add them together.
However, while you might be able to see and keep in memory
one image very well, you will have less ability as the number of images
increase, and you may find that one image interferes with another.
For example, if you are driving while trying to think about
and visualize the solution to some kind of problem, your thoughts
could well interfere with your driving. I found this out for myself
when I was trying to multiply some numbers in my mind and took
the wrong turn-off because I was distracted by seeing the problem
in my mind. But if you are only listening to music on the radio or to
someone speaking without forming images, that will not interfere—
or at least to the same degree.
You might think of this process of trying to work with more and
more images at the same time as looking at the windows on a computer
screen. As you add more windows to work with at the same
time, the individual windows get smaller and smaller, as do the images;
you are less able to see what is in each image distinctly, and
your attention to one window may be distracted by what is flashing
by in another.
Intriguingly, brain researchers (also called neuroscientists) have
found that these images you see in your visuospatial sketchpad correspond
to real places in your brain. As neuroscientists have found,
when you work with a visual image, it activates the right hemisphere
of your cortex, the top section of your brain, and in particular they
activate the occipital lobe, at the rear of your cortex. Then, as you
engage in some mental task involving this image, your frontal lobe
will get in on the action, too.
Researchers have been able to tell what part of the brain is associated
with different types of thinking by using PET (positron emission
tomography) scans, where they measure the blood flow to the
brain by injecting a person with a radioactive chemical just before
they perform some kind of mental task. They find that certain
sections of the brain have more blood flow, indicating more activity
there for different types of mental tasks. 23