Memory

Memory
1
‫تخصصی‬ ‫کارگاه‬
‫حافظه‬ ‫توانبخشی‬
‫شناختی‬ ‫های‬ ‫هفته‬ ‫آخر‬ ‫های‬ ‫کارگاه‬ ‫سری‬ ‫از‬
Faezeh Dehghan. OTR. PhD student of neuroscience
Iran university of medical science

Memory
• the ability to take in, store, and retrieve information
• Baddeley and Hitch (1974), influenced by Atkinson and
Shriffin (1971), suggested that memory can be divided
into three categories broadly based on the length of time
information can be stored:
• sensory memory
• short-term store, which holds information for a few
seconds
• long-term store, which holds information for anything
from minutes to years
2

The Role of Attention in Memory
• In order to encode information into memory, we must first pay
attention, a process known as attentional capture.
• Attentional Capture
• In order for information to be encoded into memory, we must first
pay attention to it.When a person pays attention to a particular
piece of information, this process is called attentional capture.
• By paying attention to particular information (and not other
information), a person creates memories that could be (and
probably are) different from someone else in the same situation.
This is why two people can see the same situation but create
different memories about it—each person performs attentional
capture differently.
• There are two main types of attentional capture: explicit and
implicit.
4

• Explicit Attentional Capture
• Explicit attentional capture is when a stimulus that a
person has not been attending to becomes salient
enough that the person begins to attend to it and
becomes cognizant of its existence.
• Very simply, it's when something new catches your focus
and you become aware of and focused on that new
stimulus.
5

• Implicit Attentional Capture
• Implicit attentional capture is when a stimulus that a
person has not been attending to has an impact on the
person's behavior, whether or not they're cognizant of
that impact or the stimulus.
• If you are working on your homework and there is quiet
but annoying music in the background, you may not be
aware of it, but your overall focus and performance on
your homework might be affected.
6

Sensory Memory
• During every moment of an organism's life, sensory information is being
taken in by sensory receptors and processed by the nervous system.
• Sensory information is stored in sensory memory just long enough to be
transferred to short-term memory
• Sensory memory types
• Visual sensory memory—brief memory of an image or icon.Also called
iconic memory.
• Auditory sensory memory—brief memory of a sound or echo.Also called
echoic memory
• Haptic memory - Haptic memory represents SM for the tactile sense of
touch. Sensory receptors all over the body detect sensations such as
pressure, itching, and pain. Information from receptors travel through
afferent neurons in the spinal cord to the postcentral gyrus of the parietal
lobe in the brain.This pathway comprises the somatosensory system.
7

Sensory Memory
Function —process for basic physical characteristics
Capacity—large , can hold many items at once
Duration—very brief retention of images 3 sec for visual
info, 2 sec for auditory info
Divided into two types:
▪ iconic memory–visual information
▪ echoic memory– auditory information
Attention is needed to transfer information to working
memory
8

Short-Term Memory
• Function—conscious processing of information
• where information is actively worked on
• Capacity—limited (holds 7+/-2 items)
• Duration—brief storage (about 30 second )
• Primary memory and immediate memory refer to the memory
span as measured by the number of digits that can be repeated
in the correct order after one presentation (seven plus or minus
two for the vast majority of people)
9

Maintenance Rehearsal
• Mental or verbal repetition of information allows information
to remain in working memory longer than the usual 30 seconds
• This type of rehearsal usually involves repeating information
without thinking about its meaning or connecting it to other
information.This is why the information is not usually
transferred to long term memory
• An example of maintenance rehearsal would be remembering
a phone number only long enough to make the phone call.
10

Elaborative rehearsal
• Elaborative rehearsal is a type of memory rehearsal that is
useful in transferring information into long term memory.
• This type of rehearsal is effective because it involves thinking
about the meaning of the information and connecting it to
other information already stored in memory. It goes much
deeper than maintenance rehearsal.
• According to the levels-of-processing effect by Fergus I. M.
Craik and Robert S. Lockhart in 1972, this type of rehearsal
works best because of this depth of processing.
11

Chunking
• Grouping small bits of information
into larger units of information
▪ expands working memory load
▪Which is easier to remember?
▪ 4 8 3 7 9 2 5 1 6
▪ 483- 792- 516
• ‫انار‬ ‫با‬ ‫سیب‬
‫سگ‬ ‫با‬ ‫گربه‬
• ‫گربه‬ ‫با‬ ‫قرمز‬
‫موش‬ ‫با‬ ‫آبی‬
12

Long-Term Memory
• the long-term store or long-term memory (LTM) is the system that
stores information for longer periods of time ranging from
minutes to decades.
• Once information passes from sensory to working memory, it can
be encoded into long-term memory
• Function—organizes and stores
• information
• more passive form of storage than working memory
• Unlimited capacity
• Duration—thought by some to be permanent
• Encoding—process that controls movement from working to
long-term memory store
• Retrieval—process that controls flow of information from long-
term to working memory store
13

• LTM can be understood or distinguished in various ways,
including semantic, episodic, and procedural memory;
visual and verbal memory; and implicit and explicit
memory.
15

Types of Long-Term Memory
• Explicit memory—memory with awareness; information
can be consciously recollected; also called declarative
memory
• Implicit memory—memory without awareness; memory
that affects behavior but cannot consciously be recalled;
also called nondeclarative memory
17

Explicit Memory
• Declarative or conscious memory
▪ Memory consciously recalled or declared
▪ Can use explicit memory to directly respond to a
question
▪Two subtypes of explicit
• Episodic information—information about events or
“episodes”
• Semantic information—information about facts, general
knowledge, school work
18

semantic memory
• Memory not tied to personal events
▪ General facts and definitions about the world
• We use semantic memory when we answer questions such
as the color of a banana, the capital of Egypt, whether a cat
is larger or smaller than a elephant , and the meaning of the
word justice.
• We have a huge store of information as to what things
mean, look like, sound like, smell like, and feel like.
• Does NOT depend on tying the item to your past
19

episodic memory
• Memory tied to your own personal experiences
• episodic memory: Memory for personal experiences (e.g.,
where you spent last Christmas, when the credit card bill
was paid, or what your friend asked you to do this
evening) is more autobiographical to travel back in time
• Episodic memory problems, like semantic memory
problems, result from deficits in LTM.
20

procedural memory
• Memory for skills or routines is known as procedural memory.
Learning to ride a bicycle, reading words written back to
front, and learning to type are examples of procedural
learning.
• The primary characteristic of this kind of learning is that it
does not depend on conscious recollection; instead, the
learning can be demonstrated without the need to be aware
of where and how the original learning took place.
• For this reason, most people with memory problems show
normal or relatively normal procedural learning
• Some patient groups are known to show impaired
procedural learning, particularly those with Huntington’s
disease and Parkinson’s disease
21

Stages in the Process of Remembering:
Encoding, Storage, and Retrieval
• The taking in of information is the encoding stage, retaining the
information is the storage stage, and accessing the information when
required is the retrieval stage.
• encoding information (learning it, by perceiving it and relating it to
past knowledge), storing it (maintaining it over time), and then
retrieving it (accessing the information when needed). Failures can
occur at any stage, leading to forgetting or to having false memories.
• Encoding is the crucial first step to creating a new memory. It allows
the perceived item of interest to be converted into a construct that
can be stored within the brain, and then recalled later from short-
term or long-term memory.
22

• Memory: Persistence of learning over time through the storage and
retrieval of information
• STEPS: External events  sensory memory  short term/working
memory  long term memory
• WM:Automatic or effortful encoding
• Can be aided by the timing of rehearsals, imagery, and mnemonic devices
• WM has short duration and limited capacity
• LTM: is limitless and constructive
• Works by leaving traces of neural impulses
• Long term potentiation  permanent change in synapses
• Stress hormones influence memory
• We have implicit (cerebellum) and explicit (hippocampus)LTM
• Retrieval of information happens by recall, recognition
• Priming (unconscious), context effects, and mood congruence help us retrieve
relevant information
23

Memory Encoding
• Encoding is a biological event beginning with perception through the senses.
• The process of laying down a memory begins with attention (regulated by the thalamus and the frontal
lobe), in which a memorable event causes neurons to fire more frequently, making the experience more
intense and increasing the likelihood that the event is encoded as a memory.
• Emotion tends to increase attention, and the emotional element of an event is processed on an
unconscious pathway in the brain leading to the amygdala. Only then are the actual sensations derived
from an event processed.
• The perceived sensations are decoded in the various sensory areas of the cortex, and then combined in the
brain’s hippocampus into one single experience.
• The hippocampus is then responsible for analyzing these inputs and ultimately deciding if they will be
committed to long-term memory.
• It acts as a kind of sorting center where the new sensations are compared and associated with previously
recorded ones.
• It is also one of the few areas of the brain where completely new neurons can grow.
26

• There are three or four main types of encoding:
• Acoustic encoding is the processing and encoding of sound, words and
other auditory input for storage and later retrieval.This is aided by the
concept of the
• Visual encoding is the process of encoding images and visual sensory
information.Visual sensory information is temporarily stored within the
iconic memory before being encoded into long-term storage.
• The amygdala (within the medial temporal lobe of the brain which has a
primary role in the processing of emotional reactions) fulfills an important
role in visual encoding, as it accepts visual input in addition to input from
other systems and encodes the positive or negative values of conditioned
stimuli.
• Tactile encoding is the encoding of how something feels, normally through
the sense of touch. Physiologically, neurons in the primary somatosensory
cortex of the brain react to vibrotactile stimuli caused by the feel of an
object.
• Semantic encoding is the process of encoding sensory input that has
particular meaning or can be applied to a particular context, rather than
deriving from a particular sense.
27

Encoding Specificity
• When conditions of retrieval are similar to conditions of
encoding, retrieval is more likely to be successful
–You are more likely to remember things if the conditions
under which you recall them are similar to the conditions
under which you learned them
Context effects—environmental cues to recall
• State dependent retrieval—physical, internal factors
• Mood Congruence—factors related to mood or emotions
28

Flashbulb Memories
• Recall of very specific images or details about a vivid, rare, or
significant event
• May seem very vivid and specific, but they are not more accurate
than ordinary memories
• A flashbulb memory is a detailed and vivid memory that is stored on
one occasion and retained for a lifetime. Usually, such memories are
associated with important historical or autobiographical events.
• Flashbulb memories are thought to require the participation of the
amygdala, a brain structure involved in emotional memory, and
possibly other brain systems which regulate mood and alertness.
29

MEMORY STORAGE
• Storage is the more or less passive process of retaining
information in the brain, whether in the sensory
memory, the short-term memory or the more
permanent long-term memory.
• Each of these different stages of human memory
function as a sort of filter that helps to protect us from
the flood of information that confront us on a daily basis,
avoiding an overload of information and helping to keep
us sane.
• process of consolidation, the stabilizing of a memory
trace after its initial acquisition
30

MEMORY RECALL/RETRIEVAL
• Recall or retrieval of memory refers to the subsequent
re-accessing of events or information from the past,
which have been previously encoded and stored in the
brain.
• In common parlance, it is known as remembering.
• During recall, the brain "replays" a pattern of neural
activity that was originally generated in response to a
particular event, echoing the brain's perception of the
real event.
• In fact, there is no real solid distinction between the act
of remembering and the act of thinking.
31

ForgettingTheories
• Encoding failure
▪ Interference theories
▪ Motivated forgetting
▪ Decay
32

Forgetting as encoding failure
 Some information is encoded without effort
 Some information requires effortful encoding or it never
enters long-term memory
External
events
Sensory
memory
Short-
term
memory
Long-
term
memory
Attention
Encoding
Encoding
Encoding
failure leads
to forgetting 33

InterferenceTheories
• Memories interfering with memories”
• Forgetting NOT caused by mere passage of time
• Caused by one memory competing with or replacing another
memory
▪Two types of interference
34

Forgetting as retrieval failure
 Forgetting can result from failure to retrieve information from
long-term memory
External
events
Attention
Encoding
Encoding
Retrieval failure
leads to forgetting
Retrieval
Sensory
memory
Short-term
memory
Long-term
memory
35

• There are two main methods of accessing memory: recognition and
recall.
• Recognition is the association of an event or physical object with one
previously experienced or encountered, and involves a process of
comparison of information with memory, e.g. recognizing a known
face, true/false or multiple choice questions, etc.
• Recognition is a largely unconscious process, and the brain even has
a dedicated face-recognition area, which passes information directly
through the limbic areas to generate a sense of familiarity, before
linking up with the cortical path, where data about the person's
movements and intentions are processed.
• Recall involves remembering a fact, event or object that is not
currently physically present (in the sense of retrieving a
representation, mental image or concept), and requires the direct
uncovering of information from memory, e.g. remembering the
name of a recognized person, fill-in the blank questions, etc.
36

• Recognition is usually considered to be “superior” to recall (in
the sense of being more effective), in that it requires just a
single process rather than two processes.
• Recognition requires only a simple familiarity decision, whereas
a full recall of an item from memory requires a two-stage
process (indeed, this is often referred to as the two-stage theory
of memory) in which the search and retrieval of candidate items
from memory is followed by a familiarity decision where the
correct information is chosen from the candidates retrieved.
• Thus, recall involves actively reconstructing the information and
requires the activation of all the neurons involved in the
memory in question, whereas recognition only requires a
relatively simple decision as to whether one thing among others
has been encountered before.
• Sometimes, however, even if a part of an object initially
activates only a part of the neural network concerned,
recognition may then suffice to activate the entire network
37

• Free recall is the process in which a person is given a list of items to
remember and then is asked to recall them in any order (hence the name
“free”).
• This type of recall often displays evidence of either the primacy effect (when
the person recalls items presented at the beginning of the list earlier and
more often) or the recently effect (when the person recalls items presented
at the end of the list earlier and more often).
• Cued recall is the process in which a person is given a list of items to
remember and is then tested with the use of cues or guides.When cues are
provided to a person, they tend to remember items on the list that they did
not originally recall without a cue, and which were thought to be lost to
memory.
• This can also take the form of stimulus-response recall, as when words,
pictures and numbers are presented together in a pair, and the resulting
associations between the two items cues the recall of the second item in the
pair.
• Serial recall refers to our ability to recall items or events in the order in which
they occurred, whether chronological events in our autobiographical
memories, or the order of the different parts of a sentence (or phonemes in a
word) in order to make sense of them.
38

• Testing of serial recall by psychologists have yielded several general rules:
1. more recent events are more easily remembered in order (especially with
auditory stimuli)
2. recall decreases as the length of the list or sequence increases;
3. there is a tendency to remember the correct items, but in the wrong
order;
4. where errors are made, there is a tendency to respond with an item that
resembles the original item in some way (e.g. “dog” instead of “fog”, or
perhaps an item physically close to the original item);
5. repetition errors do occur, but they are relatively rare;
6. if an item is recalled earlier in the list than it should be, the missed item
tends to be inserted immediately after it;
7. if an item from a previous trial is recalled in a current trial, it is likely to be
recalled at its position from the original trial.
39

• Colour may have an effect on our ability to memorize
something.
People remember colour scenes better than black-and-
white ones, although only if naturally (as opposed to
falsely) coloured.
In particular, warm colours, like red, yellow and orange,
may help us to memorize things by increasing our level
of attention (our ability to select from information
available in the environment).
40

Memory development
• The development of memory in children becomes evident
within the first 3 years of a child's life as they show
considerable advances in declarative memory.
• This enhancement continues into adolescence with major
developments in short term memory, working memory, long
term memory and autobiographical memory
• Recent research on the development of memory has indicated
that declarative, or explicit memory, may exist in infants who
are even younger than two years old. For example, newborns
who are less than 3 days old demonstrate a preference for their
mother’s own voice
42

• Declarative memory develops very rapidly throughout the first
2 years of life; infants of this age show evidence of cognitive
development in many ways (e.g., increased attention,
language acquisition, increasing knowledge).
• There is a difference in the brain development of explicit and
implicit memory in infants.
• Implicit memory is controlled by an early-developing memory
system in the brain that is present very early on, and can be
explained by the early maturation of striatum, cerebellum, and
brain stem, which are all involved in implicit learning and
memory.
43

• Development of explicit memory depends on a later
developing memory system in the brain that reaches
maturity between 8 and 10 months of age.
• Explicit memory depends heavily on structures in the
medial temporal lobe, including the hippocampus and the
parahippocampal cortex. Much of the brain system is
formed before birth, however the dentate gyrus within
the hippocampal formation has about 70% of the number
of cells in adults
44

• Working Memory
• According to Baddeley's model of working memory, working memory
is composed of three parts. First is the central executive which is
responsible for a range of regulatory functions including attention,
the control of action, and problem solving. Second, the phonological
loop, which is specialized for the manipulation and retention of
material in particular informational domains.
• Finally, the visuospatial sketchpad stores material in terms of its
visual or spatial features.The strength of the relationships between
the three components of working memory vary; the central executive
is strongly linked with both the phonological loop as well as the
visuospatial sketchpad which are both independent of each other.
Some evidence indicates linear increases in performance of working
memory from age 3-4 years through to adolescence
45

• Central Executive
• In children from 2-4, the memory storage capacity limitation constrains
complex comprehension processes. As the child grows older however,
less processing is necessary which opens more storage space for memory
• Phonological Loop
• Evidence indicates linear increases in performance from age 4 years
through to adolescence. Prior to about 7 years of age, serial recall
performance is mediated by the phonological store which is one
component of the phonological loop.
• Preschool aged children do not use a subvocal rehearsal strategy to
maintain decaying phonological representations in the store but instead
they identify visual features of pictures in order to remember them.
• At the age of seven, children begin to use a subvocal rehearsal process to
maximize retention in the phonological store.
46

• Visuospatial Sketchpad
• Younger children (under the age of 5) may be dependent than
older children or adults on using the visuospatial sketchpad to
support immediate memory for visual material.
• Older children adopt a strategy of verbally recoding pictures
where possible and also use the phonological loop to mediate
performance of the “visual” memory task.
• Between the ages of 5 and 11, visual memory span increases
substantially and it is at this point when adult levels of
performance are reached
47

Memory rehabilitation
• Data is important!
• Accurate input = Accurate recall
• Coding –decoding (all sensory system)
• First start with procedural memory
48

54
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