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Memory
Li, Kristoffer Daniel
Lee, Seoui
What is Memory?
An active system that receives information
from the senses, puts that information into
usable form, organises it as it stores it away,
and then retrieves the information from
storage (adapted from Baddely, 1996, 2003)
Three Processes of
Memory
Encoding
Retrieval
Storage
Encoding
The set of mental operations that people
perform on sensory information to convert that
information into a form that is usable in the
brain’s storage system.
Storage
Holding on to some information for a period of
time.
Retrieval
Getting information that is in storage into a
form that can be used
Models of Memory
Information-Processing
Model
Levels of Processing
Model
Parallel Distributed
Processing (PDP) Model
Information-Processing
Model
Model of memory that assumes the
processing of information for memory
storage is similar to the way a computer
processes memory in a series of three
stages.
Parallel Distributed
Processing Model
A model of memory in which
memory processes are proposed to
take place at the same time over a
large network of neural
connections.
Levels of Processing
Model
Information processed according to
its meaning, rather than sound or
physical characteristics of the word,
will be remembered more efficiently
and for a longer period of time.
The Information-Processing Model:
Three Memory Systems
Sensory Memory: How does
it work?
the very first stage of memory, the
point at which information enters
the nervous system through the
sensory systems.
Iconic Sensory Memory
Visual sensory memory,
lasting only a fraction of a second.
Capacity of Iconic Sensory
Memory
The capacity of iconic memory is
everything that can be seen at one time.
Duration of Iconic Memory
In real life, information that has just
entered iconic memory will be pushed
out very quickly by new information, a
process called masking (Cowan, 1988).
Research suggests that after only a
quarter of a second, old information is
replaced by new information.
Although it is rare,
some people do
have what is properly
called eidetic
imagery, or the ability
to access a visual
sensory memory over
a long period of time.
Echoic Sensory Memory
echoic memory is the
brief memory of
something a person
has just heard. It is
limited to any can be
heard at any one
moment and lasts
about 2-4 seconds.
Short-Term Memory
the memory system in which information is
held for brief periods of time while being used.
This is possible through the process of selective
attention, the ability to focus on
only one stimulus from among all sensory input
Selective Attention
First Stage: incoming stimuli in sensory memory
are filtered on the basis of simple physical
characteristics.
Second Stage: the processing of only the
stimuli that meet a certain threshold of
importance.
Working Memory
an active system that
processes the
information in shortterm memory.
Techniques to Remember
Chunking
Maintenance
Rehearsal
Long Term Memory
the system of memory into which all the
information is placed to be kept more or
less permanently.
Elaborative Rehearsal
method of transferring information
from STM into LTM by making that
information meaningful in some
way.
Types of Long-Term
Information
Procedural
(Nondeclarative)
LTM
• Implicit Memory
Declarative LTM
• Semantic Memory
• Episodic Memory
Procedural LTM
Includes memory for skills, procedures, habits
and conditioned responses. These memories
are not conscious but are implied to exist
because they affect behaviour; also Implicit
Memory.
Declarative LTM
Contains information that is conscious
and known; also, explicit memory.
Semantic Memory
Type of declarative memory containing
general knowledge.
Episodic Memory
Type of declarative memory containing
personal information that are not readily
available to others.
LTM Organisation: Semantic
Network Model
Retrieval of Long Term
Memories
Encoding Specificity
The tendency for memory of information to be
improved if related information that is available when
the memory is first formed is also available when the
memory is being retrieved.
Recall vs Recognition
The Serial Position Effect
Tendency of information at the beginning (Primacy
Effect) and end (Recency Effect) of a body of
information to be remembered more accurately than
information in the middle.
False Positive
Error of recognition in which people think they
recognise some stimulus that is not actually in
memory.
Automatic Encoding
Tendency of certain kinds of information to
enter LTM with little or no effortful encoding.
Flashbulb Memories
Type of automatic encoding that occurs
because an unexpected event has strong
emotional associations for the person
remembering it.
The Reconstructive Nature
of Long-Term Memory
Retrieval
How Reliable Are Memories?
Constructive Processing
of Memories
• Memories are rarely completely accurate and
become less accurate over time.
• Loftus and others have suggested that memory
retrieval is a constructive process; memories are
“built” at the time of retrieval.
• Hindsight bias – “knew-it-all-along”
Memory Retrieval
Problems
• The Misinformation Effect
o Misleading information can become part of the actual
memory, affecting its accuracy.
Reliability of Memory
Retrieval
• False memory syndrome
o Creation of inaccurate or false memories through the
suggestion of others, often while the person in under
hypnosis
1. The event must be made to seem as plausible as
possible.
2. Individuals are given information that helps them
believe that the event could have happened to
them personally.
Forgetting
Mnemonist
The Forgetting Curve
• Distributed practice
o Produces far better retrieval than massed practice
(cramming)
• Encoding failure
o Nonattended information is not encoded into memory
• Memory trace decay
o Over time, if not used, neuronal connection can weaken
or decay
• Interference
o Other information interferes with accurate retrieval
o Proactive: previously learned
o Retroactive: newly acquired
Neuroscience of
Memory
Different brain areas are associated with
different types of memory
• Procedural memories: cerebellum
• Short-term memories: prefrontal cortex and
temporal lobes
• Semantic and episodic long-term memories: frontal
and temporal lobes
Consolidation
• Several physical change in brain are associated
with memory formation
o Changes at receptor
• Long-term potentiation – changes in the sensitivity of
the synapse through repeated stimulation
o Changes in dendrites
• 4E-BP2
H.M.
Hippocampus
• Plays a vial role in the formation of new declarative
long-term memory.
Organic Amnesia
• Caused by problems in brain function associated
with brain trauma, disease or aging.
• Retrograde
o Loss of memory from the point of injury backwards
• Anterograde
o Loss of memory from the point of injury forwards
Infantile Amnesia
• Memories before age 3 are likely implicit, not
explicit.
• Social relationships
o Children develop autobiographical memory.