CHAPTER SUMMARY
CHAPTER SUMMARY
- Memory is the process involved in retaining, retriev-
ing, and using information about stimuli, images,
events, ideas, and skills after the original information
is no longer present. It is important for dealing with
day-to-day events, and cases such as Clive Wearing’s
illustrate the importance of memory for normal
functioning. - Atkinson and Shiffrin’s modal model of memory consists
of three structural features—sensory memory, short-term
memory, and long-term memory. Another feature of the
model is control process such as rehearsal and atten-
tional strategies. - Sperling used two methods, whole report and partial
report, to determine the capacity and time course of
visual sensory memory. The duration of visual sensory
memory (iconic memory) is less than 1 second, and of
auditory sensory memory (echoic memory) about 2–4
seconds. - Short-term memory is our window on the present.
Brown, and Peterson and Peterson, determined that the
duration of STM is about 15–20 seconds. They inter-
preted the short duration of STM as being caused by
decay, but a later reanalysis of their data indicated it was
due to proactive interference. - According to George Miller’s classic seven plus or
minus two paper, the capacity of STM is 5 to 9 items.
According to more recent experiments, the capacity is
about 4 items. The amount of information held in STM
can be expanded by chunking—combining small units
into larger, more meaningful ones. Examples of chunking
are the memory performance of the runner S.F. and how
chess masters use their knowledge of chess to remember
chess piece positions. - Information can be coded in STM in terms of sound
(auditory coding), vision (visual coding), and meaning
(semantic coding). Auditory coding was illustrated by
Conrad’s experiment that analyzed the type of errors
made in memory for letters. Visual coding was illustrated
by Della Sala’s recalling visual patterns experiment, and
semantic coding by Wickens’ release from proactive
interference experiment. - The short-term memory component of the modal model
was revised by Baddeley to deal with results that couldn’t
be explained by a single short-term process. In this new
model, working memory replaces STM. - Working memory is a limited-capacity system for stor-
age and manipulation of information in complex tasks.
It consists of three components: the phonological loop,
which holds auditory or verbal information; the visuo-
spatial sketch pad, which holds visual and spatial infor-
mation; and the central executive, which coordinates
the action of the phonological loop and visuospatial
sketch pad.- The following effects can be explained in terms of opera-
tion of the phonological loop: (a) phonological similar-
ity effect; (b) word length effect; and (c) articulatory
suppression. - Shepard and Metzler’s mental rotation experiment illus-
trates visual imagery, which is one of the functions of
the visuospatial sketch pad. Brooks’s “F” experiment
showed that two tasks can be handled simultaneously if
one involves the visuospatial sketch pad and the other
involves the phonological loop. Performance decreases if
one component of working memory is called on to deal
with two tasks simultaneously. - The central executive coordinates how information is
used by the phonological loop and visuospatial sketch
pad, and can therefore be thought of as an attention con-
troller. Patients with frontal lobe damage have trouble
controlling their attention, as illustrated by the phenom-
enon of perseveration. - The working memory model has been updated to
include an additional component called the episodic buf-
fer, which helps connect working memory with LTM
and which has a greater capacity and can hold informa-
tion longer than the phonological loop or visuospatial
sketch pad. - Behaviors that depend on working memory can be dis-
rupted by damage to the prefrontal cortex. This has
been demonstrated by testing monkeys on the delayed-
response task. - There are neurons in the prefrontal cortex that fire to
presentation of a stimulus and continue firing as this
stimulus is held in memory. - Brain imaging experiments in humans reveal that a large
number of brain areas are involved in working memory.
Event-related potential (ERP) studies have provided
physiological evidence supporting the idea that a more
efficient working memory is associated with the ability
to focus on relevant information and filter out irrelevant
information. - There is a great deal of evidence that having a larger or
more efficient working memory is associated with better
comprehension, reasoning ability, and intelligence.
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