MEMORYYear 12 Psychology Unit 3Area of Study 2

(Chapter 6, Page 286)

Memory Storage & retrieval of information acquired through learning:

Internal record/representation of prior events/experiences.

A collection of complex interconnected systems: Each serve a different purpose and operate in a very different way. All receive, process and store info for future use.

Memory is not perfect: We often fail to process & store all info we are exposed to or all

info that we need.

When receive sensory info, brain must select what is attended to, processed and stored in various memory systems.

Activity: 6.2

MEMORY:INFORMATION PROCESSING SYSTEM Receives, organises, stores and recovers info. Like a computer, it does not passively receive and store new

info, rather it actively alters and organises incoming info so that it can be stored in a way that is easily retrieved.

Considered an information processing system because of three key processes:

Stages of Memory

Sensory Memory

Short-term Memory

Long-term Memory

External stimulus

Forgetting

Attention

Rehearsal

ForgettingResponse

Storage

Retrieval

Internal stimulus (thoughts)

Forgetting

STAGES OF MEMORY:SENSORY MEMORY Function - receives sensory info from environment.

Entry point for new info which is retained in original sensory form (held as exact copies and not encoded).

Capacity - unlimited. Can store all sensory experiences (briefly).

Duration - 0.2sec-4sec. Sensory impressions stored just long enough to slightly

overlap (so we perceive the world as continuous, rather than disconnected sensations).

Sensory info remains long enough for us to attend to and select the info to be transferred to STM.

STAGES OF MEMORY:SENSORY MEMORY  Not consciously aware of the majority of info

entering. Only become aware when attention is directed to toward it in the process of transferring it to STM.

Any stimulus that is registered is available to be selected for attention and for processing in STM.

If sensory info is not attended to is it lost quickly (within seconds at most) & completely.

Info that is attended to is transferred to STM. Sensory info is stored in sub-systems called

sensory registers (e.g. iconic memory & echoic memory).

SENSORY MEMORY:ICONIC MEMORY From Greek word ‘icon’, meaning ‘image’.

Visual sensory memory or the memory of visual sensory info Stored in their original sensory form.

Unlimited capacity, brief duration (1/3 of a sec).

Info is held long enough for overlap with the next. Example: movies- a series of individual frames is

viewed as a continuously moving image.

SENSORY MEMORY:ICONIC MEMORY (STUDY) George Sperling (1960): used a tachistoscope

projector to display sets of 12 letters for one twentieth of a sec. Could only recall 4-5 letters. Reported that they had retained an image of all letters for

an instant. However, by the time they had written down 4-5 letters the remaining letters had faded from memory.

To test whether all letters were actually retained in iconic memory, sounded a tone just after the letters were flashed.

High tone – recall top row; Medium tone – recall middle; Low tone – recall bottom.

Results indicate that all the letters were stored in iconic memory (could remember that row with perfect accuracy).

Delaying the tone found out how quickly images fade in iconic memory.

Typical duration = 0.2-0.4sec.

SENSORY MEMORY:ECHOIC MEMORY Auditory sensory memory or the memory of

auditory sensory information. Processes all sounds. Stores sounds in original sensory form. Holds info for 3-4sec.

This relatively longer holding time is important for understanding speech: We hear words as syllables (individual sounds) Cannot identify word until all sounds have been heard, so

they need to be stored long enough for all the sounds to be received and then combined.

SENSORY MEMORY:ECHOIC MEMORY (STUDY)  Cowan et al. (2000): participants focused on

reading a story & ignored the numbers they heard being spoken. Signal sounded at random times during their reading.

Participants then had to repeat the last few numbers heard.

Could accurately repeat if the signal was presented immediately after the last spoken number.

Recall diminished when time between last number and the signal was delayed up to about 10sec.

Participants reported being only vaguely aware of the spoken numbers while they were reading, but when the signal sounded they could still ‘hear’ the last few numbers, could shift their attention to those numbers and could therefore repeat them.

Activity: 6.6

SENSORY MEMORY:STORING & FILTERING Can store virtually all the info provided by sensory

receptors but the info fades rapidly (rate varies among the different senses).

Info is lost & replaced so rapidly that we are rarely aware of our capability to store sensory info.

Acts as a filter to keep out irrelevant and unimportant information that could clutter our sensory stores. Would be frustrating, confusing, dangerous & inefficient to

process EVERYTHING that reached sensory memory or attend to all the sensory info that our receptors detect.

E.g. if out walking & hear car brakes screeching, will attend to & act on that incoming sensory info for your safety. In doing so, you ignore all other incoming info (other sounds, smells, etc.).

SHORT TERM MEMORY Temporarily holds all info you are

consciously thinking about at any one moment. Receives info from SM and/or LTM.

Limited storage capacity for brief periods (longer than SM), unless info is renewed in some way: Consciously repeating/rehearsing it; Using the information.

Info is encoded (unlike sensory memory).

SHORT TERM MEMORY SO, once info reaches STM there are three options:

Info can be retained in STM: By working on (attending to/using) or rehearsing the

information.

Info can be discarded: If it is not encoded, used or consciously rehearsed.

Info can be sent to LTM for storage: Requires further encoding.

SHORT TERM MEMORY SO, once info reaches STM there are three options:

Info can be retained in STM: By working on (attending to/using) or rehearsing the

information.

Info can be discarded: If it is not encoded, used or consciously rehearsed.

Info can be sent to LTM for storage: Requires further encoding.

SHORT TERM MEMORY:AKA ‘WORKING MEMORY’ STM also known as ‘working memory’ because

it is the part of memory where info you are consciously aware of is actively ‘worked on’: Processing info from sensory memory; Using/manipulating info from LTM.

Info only remains while we consciously process, examine or manipulate it. Like a mental ‘workspace’ (temporary storage facility)

for info used in conscious cognitive activity.

Computer: process new info from keyboard (sensory) & retrieve stored info from hard disk (LTM).

SHORT TERM MEMORY:DURATION Info can be held for a short period (18-20secs). Info can be kept in STM for longer than the

normal 18-20sec by maintenance rehearsal (see slide further on).

Margaret and Lloyd Peterson (1959): use of trigrams to demonstrate duration of STM. Memorise meaningless groups of 3 letters; Given a distractor (e.g. count backwards by

threes); After 3-18sec interval, recall trigrams. Longer interval = less recall.

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Activity: 6.7

SHORT TERM MEMORY:CAPACITY Limited amount of info can be held at any one

time: 7 + 2 (regardless of type of info, only 5-9 pieces

held). When STM is full, new items can only be

added by pushing old ones out. Space in STM also filled when info is

temporarily brought back form LTM. Info in STM is lost through decay (not being

used) and displacement (being pushed out).

Chunking can be used to manipulate our capacity.

SHORT TERM MEMORY: BADDELEY & HITCH (1974)MODEL OF WORKING MEMORY

Working memory has 3 sub-systems: Verbal Working memory (phonological loop): stores a limited number of

sounds (phonemes), such as words, for a short time. Time it takes to pronounce each word impacts on amount you can retain in memory. Shorter words = can rehearse more in a shorter period. Many longer words = some info lost from the limited verbal working memory system.

Visual Working memory (visuospatial sketchpad): temporarily stores visual & spatial information, such as the location of objects in the environment.

Central executive: integrates (does not store) information from the verbal & visual storage system, as well as information retrieved from LTM. Plays important role in working on info held in the two other sub-systems. Involved in processes such as calculation of mental arithmetic, decision-making. Functions like an office executive: collects info from assistants (other sub-systems)

then decides what deserves attention (to process into LTM) and what should be ignored (& consequently lost).

Suppresses irrelevant info from our conscious thought. Helps you decide what to do next, or what not to do. Can only perform one task at a time.

SHORT TERM MEMORY: BADDELEY & HITCH (1974)MODEL OF WORKING MEMORY

Limitation: Doesn’t explain how working memory actually links with LTM, SO 4th component added in 2000:

Episodic Buffer: sub-system of working memory that enables other components to interact with LTM. Not yet fully described; Limited-capacity temporary storage system that holds

about 4 chunks of information in any form; Can combine auditory & visual-spatial info and connect

those sub-systems with LTM; Episodic: ‘Pulls together’ streams of information from elsewhere

(working memory and LTM) then combines them into ‘episodes’ like movie scenes.

Buffer: Provides space to process information into episodes (edit, reorder information in an organised and meaningful way).

Also under control of the central executive.

EPISODIC BUFFER CAN BE SEEN AS A ‘MENTAL WORKBENCH’

Activity: 6.14

Pages 318 & 319

Models for Explaining Human Memory:Atkinson-Shiffrin Multi-Store Model Memory as three distinguishable components:

Sensory Register – Entry point for all new information from the external environment.

Short-Term Store – ‘Temporary working memory’ which holds information we are consciously aware of.

Long-Term Store – Holds information relatively permanently in a highly organised way (with an essentially unlimited capacity).

Model played important role in shifting study of human memory away from idea of a single system; still a useful framework, although some of its underlying ideas have since been challenged or even refuted (see page 295).

Activity: 6.3

If sensory info not attended to, its ‘memory trace’ (neural imprint) decays.

Rehearsal is needed to maintain information in short-term store.

Info may bypass short-term store & transfer directly to long-term store. BUT model did not explain how this occurred.

Considered possibility that there may be different sensory registers for different types of information (visual; auditory).

Models for Explaining Human Memory:Atkinson-Shiffrin Multi-Store Model Structural Features: Permanent, built-in, fixed

features of memory. Three different stores; Their functions; Their storage capacities; Their duration (how long information is held).

Control Processes: Selected and used by each individual & may vary across situations. Under conscious ‘control’ of the individual. Examples: attention, rehearsal, retrieval.

Activity: 6.4

SHORT TERM MEMORY:EFFECTS OF REHEARSAL Rehearsal: process of actively manipulating

info so that it can be retained in memory.

Maintenance Rehearsal: repeating info over and over to retain it in STM. Can be verbal or non-verbal; Can be retained indefinitely in STM, if not

interrupted; Does not always lead to long-term retention; Does not assist encoding info for transfer to LTM; Amount of new info that can enter STM is

restricted because of limited storage capacity (7 + 2).

SHORT TERM MEMORY:EFFECTS OF REHEARSAL

Elaborative Rehearsal: process of linking new info in a meaningful way with info already stored in memory (or with other new info), to aid in its storage and retrieval from LTM. Use of elaborative rehearsal strategies = info more likely

to be stored in LTM. The more the info is linked with other experiences the more

likely it will be remembered. More active than maintenance rehearsal. More effective (ensures info is encoded well) & efficient in

storing meaningful info.

Self-reference effect: relate new info to personal experiences and our personal situation – encoding is enhanced and therefore we are more likely to remember it.

Activity: 6.11

SERIAL POSITION EFFECT Recall is better for items at the end & beginning

of a list. The graph results in a U-shaped curve. (p.369) Primacy Effect: superior recall of items at the

beginning. Receive more attention & rehearsal, so transferred to LTM.

Recency Effect: superior recall of items at the end. Remembered because they are still in STM.

Middle items too late to be adequately rehearsed and transferred into LTM, but too early to be held in STM without rehearsal.

Serial position effect only evident if test memory immediately after learning list of items.

SERIAL POSITION EFFECT

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SHORT TERM MEMORY: CAPACITYCHUNKING Grouping separate bits of info into a larger

single unit or ‘chunk’ of info. Increases the amount of info held in STM. Improves capacity, however for permanent

storage the info MUST STILL be transferred to LTM.

Phone number length and layout: 5-5-7-8-1-9-3 versus 5578 8193

Applying meaning/significance to groups: C I A N S W F B I versus CIA NSW FBI

SHORT TERM MEMORY: CRAIK & LOCKHART (1972)LEVELS OF PROCESSING FRAMEWORK

‘Depth’ of information processing during learning determines how well it is stored in LTM.

Memories are encoded, organised & stored in LTM semantically: More meaning given to information = better storage. Continuum of processing levels: shallow to deep.

Shallow: Attend to superficial details. Deep: Apply more meaning to the information.

Limitation: difficult to quantify and measure levels of processing.

SHORT TERM MEMORY: CRAIK & LOCKHART (1972)LEVELS OF PROCESSING FRAMEWORK

Craik & Tulving (1975) experiment. Words flashed on screen for participants to process:

Semantically (meaning of the word); Acoustically (sound of the word); Visually (appearance of the word). Deeper processing (semantic encoding) led to better

memory.

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LONG TERM MEMORY Holds unlimited amounts of info for a long period

of time (the ‘memory warehouse’). Differs to STM in how info is retrieved, the form it is

stored, and the way it can be forgotten. We retrieve info from LTM using retrieval cues. Info retrieved from LTM is held in STM while it is

being used. Once info is used it can be transferred back to LTM

for continued storage. Info stored in LTM is potentially permanent

(excluding brain injury or complications).

Two storage types: Procedural & Declarative Memory

LONG TERM MEMORY:PROCEDURAL MEMORY Memory of actions and skills that have been

learned previously and involve knowing ‘how to do something’.

Also called implicit memories because it’s often hard to recall when/how we learned to perform them.

Difficult to put into words or explain how you knew the information. Riding a bike. You just ‘know’ how to do it, even if it’s

been a long time since you rode one. You would find it difficult to explain every behaviour or movement required.

LONG TERM MEMORY:DECLARATIVE MEMORY

Memory of specific facts or events that can be brought consciously to mind and explicitly stated or declared. Also called explicit memories (‘knowing that’).

Episodic Memory: holds info about specific events or personal experiences.

• Include details of time, place and the psychological/ physiological state the person was in when the event occurred.

• Like a mental diary, recording episodes we experience. Semantic Memory: stores info we have about the

world.• Includes our specialised knowledge in areas of expertise,

academic knowledge, rules, everyday general knowledge and the meaning of words.

• Facts not dependent on place or time. Both episodic and semantic memory are linked and

often hard to separate.

LONG TERM MEMORY: ORGANISATIONSEMANTIC NETWORK THEORY

Info is organised systematically in overlapping networks of concepts that are interconnected and interrelated by meaningful links. Each concept (called a node) is linked with other nodes. When we retrieve info the activation of one node causes related

nodes to be activated. Each concept is organised into a hierarchy, with subcategories. At each node, certain characteristics of that concept are stored. LTM contains thousands of concepts. Effective means of storage, enables efficient and effective retrieval of

info. Minimises duplication. Retrieval begins by searching a particular region then tracing

associations for links among concepts in that region (operates like a search engine).

Specific retrieval cue activates the relevant node/s (stored memories), which in turn activate other nodes they are linked to (related memories).

Shorter link = stronger association & less time taken to activate (retrieve).

Longer link = weaker association & more time taken to activate (retrieve).

More nodes activate = quicker retrieval of info from LTM.

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Activity: 6.21