Information Technology Reference
In-Depth Information
To solve the problem you probably subtracted the 4 from the 6 to determine
that the height of the triangular portion of the figure was 2 units. You recalled that
the formulas for the areas of a triangle and a rectangle are
1
/
2
(b)(h) and (l)(w),
respectively, and you calculated the areas to be (
1
/
2
)(5)(2)
5 units
2
and (5)(4)
=
=
20 units
2
. Adding the two, you found the total area to be 25 units
2
.
Components of the Model.
Let us see how the components of working memory
executed the task. The
central executive
, a supervisory system, controls the flow of
information to and from the other components. For instance, the decision to break
the figure into a triangle and rectangle, find the area of each, and add the two was a
function of the central executive.
The
phonological loop
, a short-term storage system for words and sounds, tem-
porarily held the formulas and the dimensions of the figure until the calculations
could be made. Information can be kept in the phonological loop indefinitely
through
maintenance rehearsal
, the process of repeating information over and over,
either out loud or silently, without altering its form (Atkinson & Shiffrin, 1968).
For example, you look up a phone number, repeat it to yourself until you dial
it, and then it is quickly lost. (We examine rehearsal in more detail later in the
chapter.)
The
visual-spatial sketchpad
, a short-term storage system for visual and spatial
information, allows you to picture the figure and see that it could be broken into
a rectangle and triangle. The visual-spatial sketchpad and the phonological loop
are independent, so each can perform mental work without taxing the resources of
the other (Baddeley, 1986, 2001). They serve the functions that historically were
attributed to
short-term memory.
“Short-term memory loss” is the phrase often
used to describe someone who has difficulty remembering specific events or peo-
ple's names. This loss actually reflects impairment in the phonological loop or, less
commonly, in the visual-spatial sketchpad.
Baddeley (1986, 2001) suggests that the phonological loop can hold about as
much information as we can say to ourselves in 1.5-2 s, and the visual-spatial
sketchpad is also limited. We examine these limitations in the next section.
A considerable amount of research has examined the working memory model
and how it impacts learning. For instance, researchers have found that learners with
attention-deficit/hyperactivity disorder (ADHD) rehearse verbal and spatial infor-
mation as effectively as healthy children, but their central executive is impaired
(Karateken, 2004), whereas learners with reading disabilities have impaired func-
tioning of the phonological loop (Kibby, Marks, & Morgan, 2004). Students with
ADHD have trouble controlling their attention and selecting effective learning
strategies, and students with reading difficulties have trouble processing verbal
information.
Limitations of Working Memory
The most striking feature of working memory is its inability to hold large amounts
of information for extended periods (Sweller, van Merrienboer & Paas, 1998).
