The document discusses memory, including the definition, physiology, stages of memory formation, theories of forgetting, types of memory such as sensory, short-term, and long-term memory, and disorders of memory. It provides details on how information is processed and stored in the brain's memory systems from initial sensory input through encoding, storage, and retrieval. Memory tests and disorders like amnesia are also briefly covered.

1. Memory
Dr. Osama Refaat
Lecturer of Psychiatry, Cairo University
Director of Training Department MOH

2. Definition
• Memory: The capacity to retain information
over time
• Memory is one of the most important concepts
in learning; if things are not remembered, no
learning can take place

3. Physiology of Memory
• Memory trace represents a biochemical and
electrophysiological change in brain
• Major areas:
– Temporal lobe
– Diencephalon
– Mammillary bodies
– Limbic system (amygdala, hippocampus, cingulate
gyrus)

4. • Major neurotransmitters:
– Acetylcholine
• Nucleus basalis of Mynert (Forebrain)
– Glutamate
• NMDA receptors

5. Stages of Memory
• Encoding: the conversion of incoming
information into a form that can be stored in
memory (memory trace).
• Storage: maintaining information in memory
over a period of time.
• Retrieval: the process of searching for stored
information and bringing it to mind.

6. Basic Reasons for Forgetting
• Encoding Failure: information did not get
into memory.
• Storage Failure: information has
disappeared from memory; it is no longer in
storage.
• Retrieval Failure: information is stored in
memory but it cannot be located.

7. Major Theories of Forgetting
• Decay Theory: information in memory
eventually disappears if it is not used. (“Use it
or lose it.”)
• Interference Theory: information stays in
memory permanently even if it is not used.
Forgetting occurs because other things we have
learned somehow prevent us from finding the
information we want
• Repression: active forgetfulness

8. Experiment
You learn a list of 10 “nonsense
syllables” (like XUG or MUW),
then get a test on it 1, 2, 4 or 8
hours later (“retention interval”).
Does it matter if you are asleep
or awake during this retention
interval?

9. We are exposed to new information when we are
awake but not when we are asleep.
Compare the amount recalled after 8
hours awake to the amount recalled after
8 hours asleep.
Your choices:
(A) Recall will be higher after being asleep.
(B) Recall will be higher after being awake.
(C) Asleep = awake.
Decay Theory predicts: ?
Interference Theory predicts: ?

10. Decay Theory predicts: C
Interference Theory predicts: A

11. Results Supported the
Syllables Recalled (out of 10)
10
Interference Theory
Asleep
5
Awake
0
0 2 4 6 8
Retention Interval

12. Types of Memory
3 types of memories:
– Sensory Memory
– Short-Term Memory
– Long-Term Memory

13. These memories differ in terms of
3 characteristics:
• Capacity: how many units of
information can be held at one time.
• Duration of Storage: how long
the information can be held.
• Reason for Forgetting: storage
failure versus retrieval failure.

14. Long-Term Memory
• Relatively permanent storage of
information

15. Long-Term Memory Contains...
Declarative Memory: Nondeclarative Memory:
Information you cannot
Information you can describe
describe
Semantic Episodic
Memory: Skilled
Memory: Habits
Personally actions
General
experienced
information
events

16. Long-Term Memory
• Capacity: virtually unlimited.
• Duration of Storage: up to a
lifetime.
• Reason for forgetting: retrieval
failure (e.g., interference).

17. Short-Term Memory
(Working Memory)
• Def: Brief storage of information
currently being used
• Capacity: 7 units, plus or minus 2
– Chunking can increase the capacity of STM
• Duration of Storage: less than 30
seconds without rehearsal.
• Reason for forgetting: storage failure
(e.g., decay, displacement).

18. Sensory Memory
• Def: Temporary storage of
information
• Capacity: large; contains most
details of sensory input.
• Duration of Storage: visual:
1/10 second; auditory: 2 seconds.
• Reason for forgetting: storage
failure (e.g., decay).

19. Forgetting

20. STM LTM
Forgetting from Short-Term Memory:
Decay or Displacement?
After information enters STM, a copy may or may
not be sent to LTM.
Soon, however, that information will disappear
from STM.
Two processes could cause information to
disappear from STM: decay and displacement.

21. STM LTM
Forgetting from Short-Term Memory:
Decay or Displacement?
Decay: information that is not rehearsed disappears
as time passes.
Displacement: information being held in STM is
pushed out by newly arriving information.
Displacement is most likely to occur when the
capacity limit of STM has been reached (about 7
units of information).

22. STM LTM
Forgetting from Short-Term Memory:
Decay or Displacement?
B R D Q L T H J
Displacement is most likely to occur when the
capacity limit of STM has been reached (about 7
units of information).

23. STM LTM
Forgetting from Short-Term Memory:
Decay or Displacement?
B R D Q L T H
J
Displacement is most likely to occur when the
capacity limit of STM has been reached (about 7
units of information).

24. Types of Interference
• Retroactive Interference:
– Recently learned information prevents recall of
earlier learned information.
• Proactive Interference:
– Earlier learned information prevents recall of later
learned information

25. • When information is learnt:
• RI:
Interferin
Target Info g Info
• PI:
Interferin
g Info Target Info

26. • When information is learnt:
• RI:
Lesson 1 Lesson 2
• PI:
Lesson 1 Lesson 2

27. Remembering

28. Basic Sequence
Sensory Short-Term Long-Term
Sensory Memory
Input Memory Memory
Suppose that you wanted to memorize the phone
number of a restaurant: 562-7837. In terms of the
model, your goal is to get this information into long-
term memory.
You look at a page of a phone book.
Scanning the page, you find the listing you want.
This is a “sensory input” to the system. The first stop
is sensory memory.

29. Basic Sequence
Sensory Short-Term Long-Term
Sensory Memory
Input Memory Memory
Attention
A copy is made in sensory memory of the visual
patterns, 562-7837.
Generally, just paying attention to something in
sensory memory moves it to short-term memory.
However, with verbal information, there is an extra
step because short-term memory prefers to take
information in an auditory form—a form you can hear.

30. Basic Sequence
Sensory Short-Term Long-Term
Sensory Memory
Input Memory Memory
Attention
This is called auditory encoding, the conversion of
visual patterns to sounds. You do this when you
“listen” to the sounds of these words on the screen.
It involves pattern recognition. Visual patterns in
sensory memory are compared to prototypes in long-
term memory.

31. Basic Sequence
Sensory Short-Term Long-Term
Sensory Memory
Input Memory Memory
Attention
Sounds corresponding to the visual patterns are then
located and copied into short-term memory. .
When you become aware of these sounds, you know
they are in short-term memory. The process of
auditory encoding has been completed.
The link from LTM to STM illustrates the process of retrieval, a
key intermediate step in memorization.

32. Basic Sequence
Sensory Short-Term Long-Term
Sensory Memory
Input Memory Memory
Attention
You have a new sequence of sounds in short-term
memory: 562-7837. Your goal is to move this
sequence into long-term memory.
There are two strategies for moving information from
STM to LTM: (1) repetition; (2) elaboration.

33. Basic Sequence
Sensory Short-Term Long-Term
Sensory Memory
Input Memory Memory
Attention Repetition
When you repeat (rehearse) information, two things
happen:
1. You recirculate it in STM. Each time you do this,
you “reset the clock” and get another few seconds
before the information decays.
2. You increase the chances that the information will
be copied into LTM. But this is an unreliable strategy.

34. Basic Sequence
Sensory Short-Term Long-Term
Sensory Memory
Input Memory Memory
Attention Elaboration
Elaboration is much more effective. You retrieve
related information from LTM and combine it with the
information you are holding in STM.
For example, you can use the letters that correspond
to the digits on the phone dial and make a word out of
the digits:

35. Basic Sequence
Sensory Short-Term Long-Term
Sensory Memory
Input Memory Memory
Attention Elaboration
5 6 2 - 7 8 3 7
L O B S T E R
Visualization works best. Try to come up with
words that refer to objects you can picture in
your “mind’s eye”.

36. Basic Sequence
Sensory Short-Term Long-Term
Sensory Memory
Input Memory Memory
Attention Elaboration
What you encode (enter into) long-term memory
is the word, lobster, and the mental picture of a
lobster. You also encode the rule, “Dial the digits
that go with the letters.”

37. Basic Sequence
Sensory Short-Term Long-Term
Sensory Memory
Input Memory Memory
Attention Elaboration
It will help if you create a mental picture that
links the lobster to the restaurant; maybe visualize
a lobster going inside, like a customer.
When it comes time to dial, the thought of the
restaurant triggers the image of the lobster, which
reminds you of your code word, “lobster”, and the
rule: “Dial the digits that go with the letters.”

38. Testing Memory
• Bed side tests
– Registration
– Short term memory (digit span: the capacity to hear
and immediately repeat back a unfamiliar sequence
of numbers)
– Long term memory
• Specialized memory tests
– WMS
• Part of cognitive battery
– CAMCOG

39. Disorders of Memory
• Amnesia:
– Anterograde
– Retrograde
– Global
– Circumscribed
• Hypermnesia
• Paramnesia:
– Retrospective Falsification
– Confabulation
– Déjà vu (illusion of familiarity)
– Jamais vu (illusion of unfamiliarity)