Chapter 10
Memory
The Evolution of Multiple
Memory Systems
• The ability to store memories and memes is
adaptive, although memories may or may
not contribute directly to fitness.
• Most of us suffer from inaccurate memories
and false memories, which can compromise
an individual's fitness.
The Information-Processing
Model of Memory
• Memory may be thought of as a three-stage
process, in which information in each stage
lasts longer than in the preceding one.
Measuring the Duration of
Sensory Memory
• George Sperling measured the duration of an icon.
Sperling projected three rows of four letters each onto a
screen for one-twentieth of a second. By "viewing" a
visual afterimage of the icon, subjects could report 3 or 4
of the 12 letters correctly. Sperling estimated that their
iconic memory of the image lasted about one-third to a
one-half second.
The Cocktail Party Phenomenon
• The process of moving
information from the
sensory store to short-term
memory is called selective
attention.
• The cocktail party
phenomenon is an
example: the ability to pick
out and selectively hear
one voice among many.
Dichotic Listening Task
• A person can pay attention to only one of two different
messages played into the ears. In dichotic listening, a
subject shadows, or repeats back, the message in one ear.
Typically, subjects can detect the physical characteristics of
sounds presented to the other ear, but not their meaning.
Chunking
• Chunking a 20-digit telephone number into
six chunks helps in memorizing it.
The Duration of Short-term
Memory
• Three to 18 seconds after
hearing three consonants
and being unable to
rehearse them, subjects
were asked to recall them.
As the time interval
between hearing and recall
increased, the percentage
of consonants the subjects
recalled decreased.
Long-term Memory for Spanish
• Researchers measured how
much Spanish people
retained years after they
had studied the language.
Surprisingly, people who
had taken several
semesters of high-school
Spanish retained 40
percent of what they had
learned, even after 50
years.
The Serial Position Effect
• After hearing a list of 20
words, subjects
immediately wrote down
as many as they could
remember, in any order.
With few exceptions, they
remembered more words
from the beginning and
end of the list than from
the middle, producing this
u-shaped function.
The Phonological Loop
• Polysyllabic words are read
at a slower rate than shorter
words, and recalled less often
in tests of memory. In this
experiment, subjects read
one-syllable words at a rate
of about 2 per second, but
four-syllable words at about
half that rate. Likewise, they
recalled 90 percent of the
one-syllable words, but less
than 50 percent of the foursyllable words.
The Primacy Effect
• The tendency for items at the beginning of a
list to be remembered better than items in
the middle.
• The primacy effect may be caused by
maintenance rehearsal: silent repetition of
each item as it is processed.
The Process of Encoding
Two Types of Encoding
Intentional Encoding
Automatic Encoding
Example: studying
Example: information
having to do with time
and place
(deep processing)
(shallow processing)
Levels of Processing
• In one experiment (Craik
& Tulving, 1975), subjects
who rehearsed words in
terms of their physical
characteristics did not
remember them well.
Subjects who rehearsed
them in the form of rhymes
or used them in sentences
remembered them better.
Elaborative Rehearsal
• A strategy of
associating a
target stimulus
with other
information at
the time of
encoding.
Implicit Memory
• The phenomenon of being influenced by the memory
of a past experience, even though you have no
conscious memory of it.
Implicit Memories Lasts Longer
than Explicit Memories
• Subjects often do not
remember the words
that prime their
responses,
suggesting that
implicit
(unconscious)
memories last longer
than explicit
(conscious)
memories.
Schemas
• A series of ten subjects
viewed and later
redrew an image from
memory. By the tenth
drawing, the original
drawing of an owl had
been transformed into
a cat through a series
The Effect of Leading Questions
• Which view is correct? Subjects viewed one of these
scenes in a series of photos showing the events leading up
to an accident. When asked later which of the nearly
identical scenes they saw, their recollections were
influenced by verbal instructions that confirmed or
disconfirmed the photo's content.of encoding distortions.
Tulving's Multiple Memory
Systems
The Mental Lexicon: Words in
Categories
The Forgetting Function
Theories of Forgetting
• Decay Theory: the theory that existing memories
interfere with the encoding and retrieval of
memories.
• Interference Theory:
– Proactive interference - interference in the learning of
new information caused by existing memories.
– Retroactive interference - interference in the retrieval of
old memories caused by newly learned information.
The Process of Retrieval from
Memory
• Retrieval cues
– Retrieval cues help people solve problems by using
available bits of information, including mnemonics,
rhymes, and songs, to direct memory searches.
• Context effects
– Context effects on memory can occur when retrieval
cues match encoding cues.
• State-dependency effects
– State-dependency effects on memory can occur when a
subject's physiological or psychological state at the time
of retrieval matches the state at the time of encoding.
Brain Areas Involved in the
Formation of Memory
Amnesia
• Two types:
– Retrograde amnesia - the loss of memory for
events that preceded a brain injury.
– Anterograde amnesia - the inability to form
new memories following an injury to the brain.