Transcript Ch 29 Memory – Encoding, Storage and Retrieval

Higher Human Biology
Unit 3: Behaviour, Populations
and environment
Chapter 29: Localisation of memory
Memory – encoding, storage and
retrieval
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Mrs Smith Ch25 The Brain
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Learning
Intentions
To examine the
workings of the
brain and the
nervous system
and its role in
Memory
Success Criteria
Describe the
processes of
encoding,
storage and
retrieval
Learning Outcomes
• To learn about the limbic system in
relation to memory storage
• To examine the process of memory –
encoding, storage and retrieval
• To compare the differences between long
and short-term memory and how memory
is transferred from STM to LTM
• To find out what causes Alzheimer’s
disease at a molecular level
Limbic System
Memory
• Memory is the brain’s
ability to store information
then retrieve it when its
needed.
• Different types of memories
are associated with different
parts of the brain.
Selective Memory
• The receptors in the human
sense organs are continuously
picking up stimuli and
transmitting impulses to the
brain.
• This results in sensory images
such as visual and acoustic
(auditory) impressions being
formed in certain areas of the
CEREBRUM.
• However only a fraction of these sensory images
become committed to memory, because this process
is highly selective.
If our memory was not selective
The mind would
become too cluttered
with useless
information such as
every phone number
ever used, every
musical note of
every tune ever
heard and so on.
The stages of memory
There are 3 stages in memorising facts and
experiences:
• encoding
• storage
• retrieval
1. Encoding
• All sensory information, before becoming part
of a memory, must be encoded - be
converted to a form that the brain can
process & store.
• Sometimes encoding is automatic, other time
it requires effort e.g. learning biological terms
There are several ways of
encoding information:
• E.g. trying to remember the word for fork in
Spanish – “tendor”
• Acoustic – say the word a few times
• Visual - visual image of a new word
• Semantic - think about the meaning of the word
• To memorise we use techniques such as
rehearsal, organisation and elaboration
Examples of Encoding
• Acoustic Coding (most common)
– If we memorise a poem, word for word
• Visual Coding (less common)
– To remember someone’s face
• Semantic Coding (less common)
– To remember the gist of a play or tv
programme
Examples of Encoding
• The majority of information received by the brain
is acoustic coding (sound). Some is also visual
or semantic (meaning).
• To remember a phone number: we usually see it
(visual), rehearse it (acoustic) and may place a
meaning to it (semantic).
• It is easier to remember items organised into groups or use
mnemonics to remember long numbers and lists of names
- twit twoo (PIN 2820)
- OILRIG
- Richard of York gave battle in vain (ROYGBIV)
2. Storage
Storage is the retention of information/memories,
over a period of time.
This may last a short amount of time or over the
course of a life time.
3. Retrieval
• Retrieval is the recovery of the stored
material.
• This involves the recall of information
which has been committed to either the
long-term or short-term memory.
Helping our retrieval skills
Easier to retrieve facts and
experiences if we are in the
same situation as we were
when it was encoded. As this
rarely happens, we rely on
contextual cues (smell,
sound, sight, person etc) to
“jog” our memory. Can use
visualisation techniques e.g.
posters for organic molecules
Summary
ENCODING
Change stimulus into a
form we can retain.
STORAGE
Store in short term
or long term
memory.
RETRIEVAL
Access when required.
Learning
Intentions
Success Criteria
To examine the
workings of the
brain and the
nervous system
and its role in
Memory
Design and carry
out an
investigation to
determine the
memory span for
letters or
numbers.
Investigating memory span
A person’s short-term
memory span can be
measured by finding out the
number of individual
‘meaningless’ items which
they can reproduce
correctly in order
immediately after seeing
and hearing them once.
Memory Span Con’ t
e.g.
Remembering objects
Recalling number series: once covered
741
2835
46279
584153
2658437
96124892
TASK: Write numbers 3 to13 below each other. I will read out
some numbers, after I read out the last digit of each series, I will
signal you to lift your pencil and write down the digits you have
just heard. Place your pencil down and I will begin the next series
Memory Experiment
Series
Number of pupils who
Number of
digits in series remember series correctly
741
3
2835
4
46279
5
584153
6
9082637
7
16136209
8
592403517
9
8076148362
10
78501942493
11
512367509308
12
6821496708754
13
Memory experiment results
• The tester will check the responses against
the first list.
• The procedure is repeated at least twice
using different lists.
• Each subjects best overall list is take to
represent his or hers memory span.
• When studying a population, such as the
class results are pooled and can be graphed.
A false memory
• Horizon Video Part 1 & 2
• http://www.bbc.co.uk/sn/tvradio/programm
es/horizon/broadband/tx/memory/false/
The effect of ‘Chunking’ on
Memory Span!
Chunking is the grouping information into one large
unit made of smaller units. This increases memory
span.
e.g. 01236 is the telephone code for Cumbernauld
so makes it easier to
remember local phone
numbers, allowing us to
remember more than we
could without chunking.
Memory Span – Chunking Con’t
• STM is only capable of holding about 7 items at
once ± 2.
• Short-term memory can be increased by
chunking. Splitting up information that needs to
be remembered into chunks (bite sized portions)
• Trying to remember the following telephone nos.:
012369871914 (12 items)
01236
Cumbernauld
Area
Code
1 item
987
(3 items)
5 items
1914
year First
World War
began
1 item
Learning
Intentions
Success Criteria
To examine the
workings of the
brain and the
nervous system
and its role in
Memory
Explain the
process involved
in transferring
information
between short
and long term
memory
Different Levels of Memory
2.
1.
Continuous
flow of
information
from
environment
Brain
constantly
forming
sensory
images
Selected
sensory
images
transferred
Short lived: Most
sensory images
quickly forgotten
Short
term
memory
limited
capacity
-7 items
3.
Long
term
memory
Some
images
transferred Unlimited
capacity
By
• Rehearsal
Many items • Organisation
forgotten • Elaboration
of meaning
Level 1 Memory
• Stimuli from the outside world are
continuously being perceived as sensory
images by the brain.
• These impressions are very short-lived.
– 0.5 secs for Visual
– 2 secs for Auditory
• Only a few of these are selected and
transferred to level 2.
Level 2 Short Term Memory
(STM)
• Most info encoded into this second level
consists of visual and auditory images.
• Used when reading. Allows us to
remember words for a few seconds so we
understand a sentence.
• Has very limited capacity – approx 7 items
so lists longer than approx 8 items almost
impossible to remember without
specialised techniques (e.g. Chunking)
Level 2 Short Term Memory
(STM)
• Not only is STM limited in capacity (7
items), the items are held for only for a
short-time (approx 30 seconds).
• During this 30 secs retrieval is very
accurate.
• STM is constantly bombarded by new
information so when extra information
added, other items are displaced.
• After the 30 secs they are either transferred
to level 3 or displaced and forgotten.
Homer explains his STM
“How is education supposed to make me feel smarter? Besides, every
time I learn something new, it pushes some old stuff out of my brain.
Remember when I took that home winemaking course, and I forgot how
to drive?”
Level 3: Long-term memory
• To retain info for any length of time, it must
be transferred to LTM – long term memory.
• This system is thought to hold an unlimited
amount of information.
• During encoding the items are organised
into categories such as facts, episodes,
skills, habit etc.
• These are then stored for a long time even
permanently.
Transfer from STM & LTM
Requires a conscious effort: Transfer methods...
1. Rehearsal - repetition
2. Organisation - grouping information into related
groups or categories.
3. Elaboration of meaning - Analysis of the
meaning of the item.
Task: Torrance-TYK pg 236 Qu 1-3
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Rehearsal
• Rehearsal is repeating something (silently
or out-loud), over and over again.
• Extends length of time held in STM and
facilitates transfer to LTM
Rehearsal:
Study tip
• Research shows that
students who regularly
stop and rehearse what
they are reading (and
trying to learn) are much more successful at
committing the information to memory than
students who read continuously and resist
taking rehearsal breaks.
• Several short rehearsal breaks are more
effective than one long rehearsal at the end
of a marathon learning session.
Serial position effect
When shown a group of similar objects, one after the other,
then asked to write down as many as possible in any order…
• Can remember objects
at start of a series
(PRIMARY EFFECT)
as there has been
time for rehearsal so it
is transferred to LTM.
• Can remember objects
at end due to objects
still being in STM
(RECENT EFFECT)
Serial Position Effect
…but it is difficult to remember the ones
in the middle because our short-term
memory is crowded and so did not allow
the transfer to long-term memory.
The images / words in the middle
are pushed out or displaced from
the STM
If it is a very unusual or
favourite item (e.g. Jeans) it
can sometimes be recalled
no matter what its position.
Serial Position Effect
In an investigation into the serial position effect, the recency
effect causes items at the end of the list to be recalled , whilst
the primacy effect helps recall of items at the start of the
sequence.
Elaboration of meaning aids transfer to long-term memory.
Organisation
Horizon clip on cues: Video 1
http://www.bbc.co.uk/sn/tvradio/progra
mmes/horizon/broadband/tx/memory/se
nses/
• Grouping items in an organised way increases their chance of
being successfully transferred from the short-term to longterm memory.
• Organised groups have contextual cues (hints) which help
the retrieval of information from the long-tem memory.
• So organisation helps the transfer of info in both directions
Organisation – grouping information into related
groups or categories.
Shortterm
memory
Longterm
memory
Past Paper MCQ 25
Q. Which of the following best describes memory?
A. The total memory capacity of the brain
B. The time taken to learn a piece of information
C. The storage capacity of the short-term memory
D. The capacity to store information in long-term
memory
Answer: Past Paper MCQ 25
Q. Which of the following best describes memory?
A. The total memory capacity of the brain
B. The time taken to learn a piece of information
C. The storage capacity of the short-term memory
D. The capacity to store information in long-term
memory
Elaboration of Meaning
Analysis of the meaning of the item to be memorised and
finding out more about it to make it more meaningful.
Short-term
memory
Long-term
memory
e.g. making a mind-map of all the
information you know helps you
learn by elaboration of meaning
This allows more connections
(more contextual cues) so more
ways to retrieve the information.
Classification of information in
the LTM
• The system of storage in the
LTM in analogous to a filing
cabinet of unlimited capacity,
organised into distinct
categories of information.
• As items are encoded and
transferred to the LTM, they
are classified and filed in
appropriate section(s).
Retrieval of Items from the LTM
The LTM contains a vast and permanent store of
remembered experience which is constantly being
revised, reorganised and enlarged as new material
flows into it.
When a piece of information needs to be called up and
retrieved from the LTM, a search is mounted. This is
aided by contextual cues.
It is thought a contextual cue somehow triggers off an
impulse through a ‘ memory circuit’.
The more powerful the contextual (e.g. A wedding day)
the more easily the experience can be retrieved.
Lapses in memory
Once the information has been transferred to the LTM, it
is stored permanently, In theory that means that it is
never forgotten, so how can failure to recall some item
that was once very well known be explained?
Sometimes we find it hard to remember if the:
• Contextual cues are weak or incomplete.
• Memory has not been retrieved for a long time.
Tip of the tongue state.
• The individual lacks sufficient
contextual cues to recall the
required information.
• However the person is armed
with a sufficient number of
cues to narrow the search and
retrieve some related
information.
• Slowly the cues lead to the
required information and the
information suddenly appears
in the conscious mind.
Retrieval of Items from the LTM
– Mnemonic devices
Tricks used to aid memory
• Rhymes e.g. ‘30 days has September….’
• Memorise simple sentence, with the first letter of
each word representing something to be
remembered
• Forming bizarre associations e.g. objects in a
room – linked to a list of things to remember
Mnemonic Devices
R
ed
O range
Y ellow
G reen
B lue
I ndigo
V iolet
Mnemonic Devices
Task: Torrance-TYK pg 239 Qu 1-4
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Task: Torrance AYK
pg240/241 Qu’s 1-6
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What you should know Ch28-29
Cloze pg 241-242
SQA Essay Questions 2010 (1A)
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SQA Essay Questions 2007 (1B)
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SQA Essay Questions 2004 (1A)
There seems to be one of
these essays every 3 years
(2004, 2007, 2010). I
wonder if there will be one
in 2013????
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