TOPIC 8: MEMORY Flashcards
Predominant view of memory
- a form of information processing; applies metaphor
- comprised of different structures (sensory,short-term, &long-term memories) and processes (encoding,storage, &retrieval)
Atkinson & Shiffrin (1968):
The Modal Model
- Sensory Memory
Sperling (1960):
Part I:
Part II:
part I:
flashed matrix of letters on screen for 50 ms:
- total recall rate: ~50%
Part II:
matrix flashed on and off / delay / tone presented
- brief delay: tested recall for desired row ~100%
- accuracy declined as delay increased
- implied complete image was temporarily stored
Iconic memory
very accurate, very brief visual sensory memory
echoic memory
auditory-based sensory memory
- Short-Term Memory (STM)
George Miller (1956): STM capacity
- measured withdigit-span task - STM capacity = “The Magical Number seven, Plus or Minus Two”
However, more recent work (Baddeley, 1994; Cowan, 2001) puts practical STS capacity at four, plus or minus one.
- chunking
digit-span task
list of numbers presented; recite them in the order of presentation
chunking
combining items into meaningful units reduces amount to be remembered
- applied in acronyms
Peterson & Peterson (1959; also Brown, 1958)
STM duration
- subjects given three consonance and a three-digit number
- during retention interval, had to count backwards by 3s - after a certain amount of time, recall the three letters
results of the Peterson and Peterson
STM fades in less than 20 seconds withoutmaintenance rehearsal
maintenance rehearsal
repeating the stimuli
Alan Baddeley (1976):
working memoryview of STM emphasizes processing of memories
- phonological loop
- visuospatial sketchpad
- episodic buffer
- central executive
phonological loop
stores sound-based information
- has phonological store & subvocal rehearsal process
visuospatial sketchpad
for solving problems “in your head”
- has visual cache & inner scribe
episodic buffer
temporary storage to/from LTM; also integrates information from other components
Central executive
attentional control system
- for coordinating the other functions
- switches between tasks, storage or retrieval strategies
- also transfers memory to/from LTM
Serial Position Effect
- shows functional division between STM and LTM
- primacy
- recency
primacy
earlier words recalled (are in LTM); due to greater rehearsal (Atkinson & Schiffrin, 1971)?
recency
later words recalled (are in STM); delaying test wipes out recency
- middle words may receive interference from both earlier and later words
- Long-Term Memory (LTM)
- capacity virtually unlimited
- duration may be unlimited–for some items, not all
•Levels of Processing(Craik & Lockhart, 1972):
- gave participants list of words to remember
- different groups encoded words differently
• shallow encoding
• intermediate encoding
• deep encoding
- different groups encoded words differently
• shallow encoding
based on appearance
• intermediate encoding
based on sound
deep encoding
based on meaning
- deeper processing enhances encoding
•elaborative rehearsal
- when encoding new memories, relate them to existing memories
- aids inmemory consolidation
memory consolidation
formation of long-term memories
•self-reference effect
- the more meaningful some information is toyou, the more likely you are to remember it
•visual images
- words that form visual images remembered best (i.e., concrete nouns vs. abstract concepts)
- words that form visual images remembered best (i.e., concrete nouns vs. abstract concepts)
- explained bydual coding theory
dual coding theory:
memory enhanced if encoded by meaningandimages
•mnemonic devices
techniques to aid memory, often by visually associating to-be-remembered items with a known series of images
method of loci:
associate each item with locations in a familiar place (e.g., a “memory palace”)
peg-word system:
relate each item to a word that rhymes with a number (e.g., one is a bun, two is a shoe, etc.)
Storage
- spread of activation
- semantic (orassociative)networks
•semantic (orassociative)networks:
related concepts in memory are interlinked
spread of activation:
thinking about one concept causes other, related concepts to become activated or “primed”
Types of Long-Term Memory
explicit (ordeclarative)memory
•implicit (ornondeclarative)memory
explicit (ordeclarative)memory
conscious, intentional remembering of knowledge or an event
- episodic
- semantic
implicit (ornondeclarative)memory
unconscious retention in memory due to previous experience
- procedural
- conditioning
- priming
episodic:
life events
semantic:
general knowledge
-conditioning:
e.g., classical or operant
-priming:
presentation of a stimulus affects response to a subsequent one
-procedural:
skills, abilities
types of amnesia:
- retrograde amnesia
* anterograde amnesia
•retrograde amnesia
inability to rememberpastepisodic memories
anterograde amnesia
inability to formnewexplicit memories
Retrieval
- recall
- recognition
- isolation effect.
recall
reproducing previously encountered information from memory
recognition
identifying previously learned information
isolation effect
a distinctive stimulus will be better remembered
“flashbulb” memories:
especially strong, vivid, and detailed memories associated with unexpected, emotionally charged events
repeated recall:
- immediately following an emotional event, record a person’s experience and memories
- compare these to a surprise reassessment at a later time
are memories for saliant events and surroundings better then those for everyday events?
yes.
encoding specificity principle:
memory retrieval is enhanced when retrieval conditions match encoding conditions
-context- dependent memory:
depends on matching external cues
results of the Godden & Baddeley (1975): does context matter?
- recall best when retrieval context retrieval learning context
state-dependent memory:
depends on matching internal states
•forgetting curve
Hermann Ebbinghaus (1885):
results from Hermann Ebbinghaus (1885):
- forgetting is rapid at first, then more gradual
- why? Nonsense is hard to remember
- also, recall depends on amount of time spent learning the list
•spacing effect
Underwood (1970):
Underwood (1970):
- participants practiced list of 42 nouns four times
- massed practice
- distributed practice
•massed practice:
information repeated in one long session
•distributed practice:
information repeated in separate sessions, with time in between
pseudoforgetting
information was not encoded in the first place, so was not forgotten
- decay theory:
memories fade with time
- interference theory:
memories compete with each other
decay:
performance will decline with time equally in both groups
interference:
sleep group will perform better than awake group
Jenkins & Dallenbach (1924): results
- sleep group had better recall
* implies that interference is responsible for forgetting
Jenkins & Dallenbach (1924):
- subjects learned nonsense syllables
- tested after certain retention interval, up to 8 hours
- one group slept, other stayed awake
retroactive interference:
new info makes it harder to remember older info.
proactive interference:
already-learned info makes it more difficult to remember new info.
misinformation effect
information given after an event can distort the memory
misinformation effect:
information given after an event can distort the memory
Loftus:
memory is reconstructive; it is a “rebuilding” of reality, not an exact copy
ohnson & colleagues (1993):
source monitering:
source monitering
making attributions about the origins of memories, knowledge, or beliefs
source failure:
not knowing the source of a memory
source confusion:
misattributing the source of a memory
repression:
active submerging of a painful memory without conscious awareness
Freud (1901):
- considered repression to be the most powerful defense mechanism used by the ego to reduce anxiety
- notconfirmed experimentally
false memory syndrome:
memory of traumatic experience which is objectively false, but in which the person strongly believes it to be true
Loftus & Pickrell (1995):
- participants were made to believe they had been lost in a shopping mall
- parents and family members kept reintroducing the topic into conversation
- researchers kept asking questions about the (false) event
- participants were initially uncertain about these memories, but gradually became more sure
results form the Loftus & Pickrell (1995):
- 29% of participants “remembered” false events
* some even provided additional details about the eventthat never happened
Karl Lashley (1950): Where are memories stored?
- trained rats to run a maze, then removed sections of brain
- performance gradually deteriorated as more brain removed
- could not localize theengram (the physical trace of a memory)
- complex memories must be distributed
Eric Kandel & colleagues (1971): How are simple memories stored?
- studied Aplysia californica (sea slug): has large, few (20,000) neurons
- examined learning via habituation: decrease in response to a stimulus due to repeated stimulus presentation
- conditioned the gill withdrawal reflex: stimulation of siphon causes gills to be withdrawn into the body
- repeated jets of water produced habituation that lasted several hours
- however, multiple daily sessions produced change in behaviour that lasted weeks
- studied synapse between siphon sensory neuron and motor neuron for gill withdrawal
- found that more neurotransmitters was released
- other studies found increased sensitivity in postsynaptic neurons, requiringless neurotransmitter to be released
what does sensory memory allow?
the transfer of information to STM
