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Chapter 7: Memory
Chapter Summary
I.
The Nature of Memory – Four common memory models are presented. Table 7.1 provides an
overview comparing each of these models.
A.
Four Models of Memory
1.
Information Processing Model – The information processing model of memory
proposes a computer model to explain how information in memory is processed using
the operations of encoding, storage, and retrieval. Encoding gets information into the
brain and is similar to a keyboard. Storage retains information like the computer’s hard
drive or disk. And, retrieval is the process of getting the information out of memory
storage.
2.
Parallel Distributed Processing Model – The PDP or connectionist model of memory
views memory as more distributed rather than a sequential operation.
3
Levels of Processing Model – Craik and Lockhart’s levels of processing model suggest
that memory relies on the degree or depth of mental processing from shallow to deeper
processing.
4.
Three-Stage Memory Model: Sensory Memory, Short-term Memory (STM), and
Long-term Memory (LTM) - This model proposes that memory needs different storage
stages to house information for various lengths of time. A flowchart for memory
processes (Figure 7.2) includes the three stages: sensory memory, short-term memory
(STM), and long-term memory (LTM).
B.
Sensory Memory - Sensory memory occurs within the senses and very briefly preserves a
replica of an image. Visual images (iconic memory) last about 1/4 to 1/2 second and auditory
images (echoic memory) up to four seconds. Sensory memory’s capacity is unclear.
C.
Short-Term Memory - STM is our conscious thoughts or working memory. It can hold
about seven (7 + or – 2) items and can store them for about thirty seconds; however, its
capacity can be increased by chunking and its duration can be increased by maintenance
rehearsal. STM may be viewed as a three-part working memory: Visuospatial Sketchpad,
Central Executive, and the Phonological Rehearsal Loop.
D.
Long-Term Memory - LTM is more permanent and has unlimited capacity. Organization of
information improves transfer and retrieval of information, as well as, sleep. LTM is divided
into two major systems – explicit/declarative and implicit/nondeclarative procedural memory.
Two types of explicit/declarative memory include semantic and episodic memory.
Implicit/nondeclarative memory includes procedural, classical conditioning, and priming.
Like priming, retrieval involves retrieval cues (recognition and recall) and the encoding
specificity principle.
Applying Psychology to Student Life: Improving Long-Term Memory (LTM)
- To successfully encode information for LTM, it is important both organize
information into chunks and into hierarchies. Rehearsal also improves encoding
for both STM and LTM and includes both maintenance rehearsal and elaborative
rehearsal. Attempting to recreate the original learning conditions by paying
attention to the retrieval cues of context, mood, and state can also improve
memory.
II.
Forgetting
A.
How Quickly Do We Forget? – Hermann Ebbinghaus’ now famous “curve of forgetting”
research demonstrated the rapidness at which information is forgotten immediately after
learning. However, he also found that relearning can occur more quickly the second time.
B.
Why Do We Forget? Five Key Theories – Five major theories have been offered to explain
why forgetting occurs: decay theory, interference theory, motivated forgetting, encoding
failure, and retrieval failure. The decay theory proposes that memory deteriorates over time
while interference theory suggests forgetting occurs when there is competing information.
Retroactive interference occurs when new information interferes with the learning of old
information and proactive interference occurs when old learning interferes with the learning
of new information. The motivated forgetting theory proposes that we may forget or inhibit
the retrieval of information that may be unpleasant, painful, or embarrassing. Encoding
failure theory may contribute to information never being encoded from STM to LTM and thus
forgotten. Retrieval failures may also contribute to the inability to recall information that is
stored in LTM.
Applying Psychology to Student Life: Recognizing Problems with Forgetting
– Four important factors that help prevent forgetting include: (1) the serial
position effect in which more forgetting occurs for material in the middle of a list
than at the beginning or end, (2) source amnesia is a result of confusion or
misattribution regarding the actual occurrence of an event, (3) the sleeper effect is
a tendency to initially discount unreliable sources and later consider it trustworthy
because the source was forgotten, and (4) the spacing of practice. Forgetting is
greatest when students use massed practice or “cramming” rather than distributed
practice with breaks in between learning.
Gender and Cultural Diversity: Cultural Differences in Memory and
Forgetting – The work of Ross and Millson (1970) used college students from the
United States and Ghana and discovered that the Ghana students were better at
memory testing for themes in stories presented aloud. Wagner (1982) found that
previous experience plays a part in facilitating memory recognition. It appears that
STM is not affected by cultural factors but that a person’s culture provides
background of experience and strategies for remembering factors specific to that
culture.
III. Biological Bases of Memory
A.
How Are Memories Formed? -The biological aspects of memory include neuronal and
synaptic changes, hormonal influences, and structures in the brain. Changes in the dendrites
occur from repeated reverberating circuits. Hormones produced during stress or excitement,
such as epinephrine and cortical play a significant role in memory. These hormones affect
areas of the brain structures in the limbic system including the amygdala, hippocampus,
cerebral cortex, and other parts of the brain. Hormonal changes during a heightened state of
emotions may produce a vivid image surrounding the event as in the phenomenon known as
flashbulb memories.
B.
Where Are Memories Located? – Lashley concluded after three decades of research in
memory that memories are distributed throughout the cortex. Current research suggests that
memory tends to be both localized and distributed throughout the brain.
C.
Biological Causes of Memory Loss – Organic causes including traumatic brain injury,
amnesia, and Alzheimer’s disease are presented. Memory loss for events that occurred before
the injury is called retrograde amnesia and memory loss for events that occur after an injury
are called anterograde amnesia. Alzheimer’s disease is a progressive mental deterioration in
memory which generally begins between the ages of 45 and 55 and may be primarily genetic.
Research Highlight: Memory and the Criminal Justice – Research studies are
presented which address two areas of memory problems including the difficulties
with eyewitness testimonies and repressed memories. Primarily because of the
constructive nature of memory the reliability of eyewitness testimonies are
questioned. The area of false versus repressed memories is a hotly contested
debate. Because of the constructive element of memory as well as source amnesia,
the misinformation effect, and the sleeper effect it is difficult to discern their
reliability.
IV. Using Psychology to Improve Our Memory
A.
Understanding Memory Distortions - The explanation for why memories are often
rearranged and distorted can be found in our need for logic, consistency as well as the need
for efficiency.
B.
Tips for Memory Improvement - Eight tips for memory improvement are highlighted: (1)
pay attention and reduce interference, (2) use rehearsal techniques – maintenance and
elaborative, (3) improve your organization, (4) counteract the serial position effect, (5)
manage your time – avoid massed practice, (6) use the encoding specificity principle-context
and state, (7) employ self-monitoring and over learning, (8) use mnemonics – the method of
loci, peg-word, substitute word, and word association, and (9) avoid the seven sins of memory
– transience, absentmindedness, blocking, misattribution, suggestibility, bias, and persistence.
Critical Thinking/Active Learning: Using Metacognition to Improve Your
Memory - The active learning exercise for this chapter allows students to practice
reflective thinking—to "think about thinking"—and to use it to evaluate processes
involved in recalling and storing memories. Students are asked to engage in a
reflective thinking activity by reflecting on their memories of the first day of their
General Psychology course.