2. Memory
LESSON OUTLINE
1. Definition of memory
2. Stages of memory/ stages of information processing (i.e.
encoding, storage and retrieval.)
3. Characteristics of memory in terms of encoding, duration
and capacity
4. Describe the multi-store model of memory: Atkinson and
Shiffrin.
5. Describe the theories of forgetting: Decay theory, Motivated
forgetting theory, Interference theory, and Cue-dependent
forgetting theory.
6. Outline the types of memory disorders.
3. Memory
Memory:
• It is defined as the ability to encode, store and retrieve
information and past experiences over time.
Cognition: defined as the processes of acquiring and
using knowledge.
Que:
• Differentiate btn Human brain and Computer
4. Stages of Memory
There are three stages of memory processing and they
include:
• Encoding: process of receiving input and
transforming it into a form or code, which can be
stored.
• Storage: process of actually putting coded
information into memory
• Retrieval: process of gaining access to stored, coded
information when it is needed.
5. Stages of Memory
1. ENCODING
When information comes into our memory system
(from sensory input), it needs to be changed into a form
that the system can cope with, so that it can be stored.
• (Think of this as similar to changing your money into
a different currency when you travel from one
country to another)
• For example, a word which is seen (on the
whiteboard) may be stored if it is changed (encoded)
into a sound or a meaning (i.e. semantic processing)
6. Stages of memory
• There are three main ways in which information can
be encoded (changed):
i. Visual (picture)
ii. Acoustic (sound)
iii. Semantic (meaning)
• For example, how do you remember a telephone
number you have looked up in the phone book?
• If you see it then you are using visual coding, but if
you are repeating it to yourself you are using acoustic
coding (by sound).
7. Stages of memory
• Evidence suggests that the principle coding system in
short term memory (STM) is acoustic coding.
• When a person is presented with a list of numbers and
letters, they will try to hold them in STM by rehearsing
them (verbally)
• Rehearsal is a verbal process regardless of whether the
list of items is presented acoustically (someone reads
them out), or visually (on a sheet of paper).
• The principle encoding system in long term memory
(LTM) appears to be Semantic coding (by meaning).
• However, information in LTM can also be coded both
visually and acoustically.
8. Stages of memory
2. STORAGE AND MEMORY
• This concerns the nature of memory stores, i.e.
where the information is stored, how long the
memory lasts for (duration), how much can be stored
at any time (capacity) and what kind of information is
held.
• The way we store information affects the way we
retrieve it.
• There has been a significant amount of research
regarding the differences between Short Term
Memory (STM) and Long Term Memory (LTM).
9. Stages of memory
• Most adults can store btn 5 and 9 items in their short-term
memory.
• Miller put this idea forward: he called it the magic number 7.
• He thought that short-term memory capacity was 7 (plus or
minus 2) items because it only had a certain number of “slots”
in which items could be stored.
10. Stages of memory
• For Short-term memory; Miller didn’t specify the amount of
information that can be held in each slot.
• Indeed, if we can “chunk” information together we can store a
lot more information in our short-term memory.
• In contrast the capacity of Long Term Memory (LTM) is
thought to be unlimited.
• Information can only be stored for a brief duration in STM
(0 – 30 seconds), but LTM can last a lifetime.
11. Stages of memory
3. RETRIEVAL AND MEMORY
• This refers to getting information out of storage.
• If we can not remember something, it may be because we are
unable to retrieve it.
• When we are asked to retrieve something from memory, the
differences between STM and LTM become very clear.
12. Stages of memory
• STM is stored and retrieved sequentially.
• For example, if a group of participants are given a list of
words to remember, and they are asked to recall the fourth
word on the list, participants go though the list in the order
they heard it in order to retrieve the information.
• LTM is stored and retrieved by association. This is why you
can remember what you went upstairs for if you go back to
the room where you first thought about it.
13. Stages of memory
• Organizing information can help aid retrieval.
• You can organize information in sequence (such as
alphabetically, by size or by time)
• Imagine a patient being discharged from the hospital whose
treatment involved taking various pills at various times,
changing their dressing and doing exercise.
• If the doctor gives these instructions in the order which they
must be carried out throughout the day (i.e. in sequence of
time), this will help the patient remember them.
14. Characteristics of memory in terms of
encoding, duration and capacity
Capacity
• How much information it can store.
Duration
• How long the information stays in the store for.
Encoding
• The way we store that particular information.
15. Characteristics of memory in terms of
encoding, duration and capacity
SENSORY MEMORY
Duration: small
Capacity: small
Encoding:
1. Haptic: encodes information from touch
2. Iconic: encodes what you see
3. Echoic: encodes things by sound
16. Characteristics of memory in terms of
encoding, duration and capacity
SHORT TERM MEMORY
Duration:
• 2-30 seconds
• Peterson & Peterson concluded that information disappears
rapidly, when rehearsal is prevented.
Capacity:
• Average 7± 2 is the average pieces of information for
individuals with the help of Digital Span Technique, which is
where someone will read something in a sequence either by:
1. Serial Recall: same order
2. Free Recall: any order.
Encoding: Echoic
• Conrad concluded that we must convert visual presented
material to an acoustic code.
17. Characteristics of memory in terms of
encoding, duration and capacity
LONG TERM MEMORY
Duration: unlimited and relatively permanent.
Capacity: unlimited
Encoding: Mainly semantic (by meaning), Baddeley 1966
18. Multi store model of memory:
Atkinson and Shiffrin
Multi store model (Atkinson and Shiffrin, 1968) is a classical
model of memory.
It is sometimes called the Modal model or the dual process
model.
Atkinson and Shiffrin (1968) suggested that memory is made
up of a series of stores.
• Multi store model describes memory in terms of information
flowing through a system.
• Information is detected by the sense organ and enters the
sensory memory.
• If attended to this information enters the short term memory.
19. Multi-store model of memory:
Atkinson and Shiffrin
• Information from the short term memory is transferred to the
long term memory only if that information is rehearsed.
• If rehearsal does not occur, then the information is forgotten,
lost from short term memory through the process of
displacement or decay.
Modifying the model:
• More goes on in short-term memory besides rehearsal; this is
now called working memory.
• Some information seems to get straight from sensory
experience into long-term memory; this is automatic
processing.
20. Working memory
• Although it is called “memory,” working memory is not a
store of memory like STM.
• It is a set of memory procedures or operations.
• One way to prevent the decay of information from short-term
memory is to use working memory to rehearse it.
Maintenance rehearsal
• It is the process of repeating information mentally or out loud
with the goal of keeping it in memory.
• We engage in maintenance rehearsal to keep a something
that we want to remember (e.g., a person’s name, e-mail
address, or phone number) in mind long enough to write it
down, use it, or potentially transfer it to long-term memory.
21. Theories of Forgetting
Forgetting (retention loss) refers to apparent loss of
information already encoded and stored in an individual’s
long term memory.
It is a spontaneous or gradual process in which old memories
are unable to be recalled from the memory storage.
The theories of Forgetting are:
• The memory Trace Decay Theory
• The Interference Theory
• The Repression or Motivated Forgetting Theory
• The displacement Theory
• The Theory of Storage Failure.
• Cue-dependent forgetting
22. The Decay theory/ Memory Traces
Decay theory
• Trace decay theory states that forgetting occurs as a result of
automatic decay or fading of the memory traces.
• Trace decay theory focuses on time and the limited duration
of short term theory
• The theory suggests that short term memory can only hold
information for between 15 and 30 seconds unless it is
rehearsed. After this time the information/ trace decays and
fades away.
• Older memories can be stronger than most recent memories.
Decay theory mostly affects short term memory.
• Long-term memory is often more resistant to shocks or
physical attacks on the brain.
23. Motivated forgetting theory
Also called the Repression theory.
Motivated forgetting arises from strong motive or desire to
forget, usually because the experience is disturbing or
upsetting to remember.
By result we push the unpleasant & painful memories into the
unconscious and thus try to avoid at least consciously the
conflicts that bother us.
This is well motivated and intentional.
This is because we like to see the world around us as quite
pleasant and reasonable.
For example,
We forget death of dearest ones/ relatives and friends.
We consciously forget marriage party which we don’t want to
occur.
24. Interference Theory
• Interference theory is also known as retrieval interference.
• Interference theory (Roediger & Karpicke, 2006) refers to the
idea that forgetting occurs because the recall of certain items
interferes with the recall of other items.
• In nature, the interfering items are side to originate from an
over stimulating environment.
25. Interference Theory
TYPES OF INTERFERENCE
Proactive interference: (pro = forward)
• Underwood (1957) provided early evidence that things you’ve
learned before encoding a target item can worsen recall of
that target item.
• In a meta-analysis of multiple experiments, he showed that
the more lists one had already learned, the more trouble one
had in recalling the most recent one.
• This is proactive interference, where the prior existence of
old memories makes it harder to recall newer memories.
26. Interference Theory
Retroactive interference: (Retro = backward)
• Retroactive interference occurs when later learning interferes
with the previous learning; i.e., learning new things somehow
overwrites or obscures existing knowledge.
27. Interference Theory
Output interference:
• Output interference occurs when the act of retrieving
interferes with the retrieval of the actual information needed
in the first place.
• Primarily, this is caused by the limited capacity of the short-
term memory.
28. Cue-dependent Forgetting
• It is the failure to recall a memory due to missing stimuli or
cues that were present at the time the memory was encoded.
• It is one of the five cognitive psychology theories of forgetting.
• It states that a memory is sometimes temporarily forgotten
purely because it cannot be retrieved, but the proper cue can
bring it to mind.
• A good metaphor for this is searching for a book in the library
without the reference number, title, author or even subject.
29. Cue-dependent Forgetting
• The information still exists, but without these cues retrieval is
unlikely.
• Further more, a good retrieval cue must be consistent with
the original encoding of the information.
• If the sound of the word is emphasized during the encoding
process, the cue that should be used should also put
emphasis on the phonetic quality of the word.
30. Summary for theories of forgetting
• Decay theory: which states that time alone causes memory
traces to fade.
• Interference theory: which suggests that other memories
interfere with remembering
• Motivated forgetting theory: which suggests that we forget
information that is unpleasant or threatening.
• Retrieval failure theory: which proposes that information
memory must be distorted when we attempt to recall it.
• Cue-dependent theory: absences of stimulus that can help
you to remember information.
