Chapter 7 - Encoding, Retrieval and Consolidation

Retrieval Encoding

Process of remembering information that has been stored in Long-Term Memory

Maintenance Rehearsal

Rehearsal that involves repetition without any consideration of meaning or making connections to other information

Elaborative Rehearsal

Rehearsal that involves thinking about the meaning of an item to be remembered or making connections between that item and prior knowledge

Levels of Processing Theory

Memory depends on how information is encoded with better memory being achieved when processing is deep than when processing is shallow. Memory depends on the depth of processing an item receives

-Shallow Processing - Processing that involves repetition with little attention to meaning, usually associated with maintenance rehearsal

-Deep Processing - Processing that involves attention to meaning and relating an item to something else. Usually associated with elaborative rehearsal 

Craik and Tulving - Level of Processing Experiment

-Presented a word, then asked participants one of 3 questions;

“Is the word in capital letters?” (Physical Feature = Shallow)

“Does it rhyme?” (Deeper processing)

“Does it complete the sentence?” (Deepest processing)

-Given a memory test after, results showed deeper processing is associated with better memory

Bower and Winzenz - Image Effect on Memory

Used the paired-associate learning - A learning task in which participants are first tested with pairs of words, then one words of each pair is presented and the task is to recall the other word

-Presented 15 pairs of nouns (ex; boat-tree) for 5 sec

-One group silently repeats the pair, the other forms an image of it

-Participants who created the mental image remembered more than twice as many words than the other group

Leshikar - Reference Effect

Self Reference Effect - Memory for a word is improved by relating the word to the self

-Self-Condition; participants look at adjectives (happy, sad) asked if it applied to them

-Common Condition - Participants look at adjectives, asked if it was a common word

In a recognition test after, the self-condition did better in remembering 

Slameka and Graf - Generation Effect

Generation Effect - Memory for material is better when person generates the material by themselves rather than passively receiving it

-Read Group - read these pairs of related words (ex; king-crown, horse-saddle)

-Generate Group - fill in the blank with a word related to the first word, ex; king-cr___ or horse-sa___)
After, participants in the generate group reproduced 28% more words than the read group, demonstrating the generation effect

Organization and Memory

Bower et al Experiment;

-One group studied 4 separate trees for various categories, then asked to recall as many words

• Participants tended to organize their responses in the way the trees were organized, recalled 73 words

-Second group studied 4 trees, but words were not separate. Participants were only able to recall 21 words

-Shows that organization is essential in memory

Nairne Experiment - Survival Effect

Performed an experiment with three conditions;

Survival Condition - Participants imagine being stranded in a foreign land, had to rate a list of words based on their survival usage

Moving Condition - Participants imagine moving, rated a list of words based on their usage in moving

Pleasantness Condition - Participants imagine how pleasant certain words are

-Survival group had the greatest level of recall, therefore a survival condition allows for better encoding and retrieval of information

Retrieving Items Assists in Encoding

When we retrieve items from our memory, it helps with encoding

Karpicke and Roediger Experiment;

Group 1 (Control Group) - Study all pairs of words, tested on all pairs. Later they studied the old pairs of words and were then tested on the pairs of words.

Group 2 (Less Studying) - Studied all pairs of words, tested on all pairs. Later, they only studied the pairs not recalled in the previous test.

Group 3 (Less Testing) - Studied all pairs of words, tested on all pairs. Then they studied all pairs but were tested on pairs not recalled in previous tests.

Testing Effect

Enhanced performance on a memory test caused by being tested on the material to be remembered 

Tino Mantyla - Retrieval Cues

Power of Retrieval Cues

-Presented participants with 504 nouns, then had participants write 3 words that they associated with each noun

-In the test phase, participants were presented with the words they generated (self-generated retrieval cues) or retrieval cues generated by others

-Results indicated that self-generated cues had a 91% remembrance rate compared to other-person generated cues with 55%

Encoding Specificity

Principle that we learn information together with its context. This means that presence of the context can lead to enhanced memory for the information

State-Dependent Learning

Principle that memory is best when a person is in the same state for encoding and retrieval

Encoding Specificity Experiment

Experiment performed by Braddley

-Participants either studied underwater then tested on land, or vice versa, or studied underwater and were tested underwater or studied on land and tested on land

-Participants who encoded information and retrieval information in the same environments did better on a memory test

-Demonstrates State-Dependent Learning

Transfer-Appropriate Processing

When the type of task that occurs during encoding matches the type of task that occurs during retrieval

Muller and Pilzecker and Consolidation

2 Groups learned nonsense syllables

-Immediate group learned one list then another with no delay

-The delay group learned one list then waited 6 minutes for the next list

When recalling, the delay group recalled 48% while the immediate group recalled 28%

-Likely due to the immediate group learning the 2nd list interrupting with the formation of a stable memory for the first list

Consolidation - Process that transfers new memories into a state more resistant to disruption

Synaptic and Systems Consolidation

Synaptic Consolidation - A process of consolidation that involves structural changes at the synapse, happens over a few minutes

Systems Consolidation - A process of consolidation that involves gradual reorganization of circuits within the brain region, takes place over a long time (weeks, months, years)

Hebb and LTP

Repeated neural activity can strengthen the synapse via structural changes, greater transmitter release, and increased firing

-Neurons that fire together, wire together

Long Term Potentiation - Increased firing that occurs in a neuron due to prior activity at the synpase

Standard Model of Consolidation

Proposes that memory retrieval and rehearsal depends on the hippocampus during consolidation, but once consolidation is complete, retrieval/rehearsal no longer uses the hippocampus

Reactivation - Occurs during memory consolidation, hippocampus replays neural activity associated with a memory, resulting in the formation of connections between cortical areas 

Evidence for Standard Model of Consolidation

If our hippocampus suffers damage, we’re likely to have amnesia

-Recent memories (those immediately prior to an injury) are fragile because they haven’t been consolidated, meaning they require the hippocampus for consolidation (so we lose them since the hippocampus is damaged)

-But earlier memories have already been consolidated and encoded into our LTM

-Makes sense in the context of being unable to form new memories. New memories require consolidation

• Example; Patient HM (hippocampus removed) couldn’t form new LTM

Types of Amnesia

Retrograde Amnesia - Loss of memory for something that happened prior to an injury or traumatic event, such as a concussion

Anterograde Amnesia - Difficulty in forming new memories after injury

Graded Amnesia - When amnesia is most severe for events that occurred immediately prior to an injury but less severe for earlier, more remote events

Multiple Trace Model of Consolidation

Idea that the hippocampus is involved in retrieval of remote memories, especially episodic

-This contrasts with SMC that proposes the hippocampus is involved only in the retrieval of recent memories 

Evidence for Multiple Trace Model

-Participants perform a paired-word task (memorizing a pair of words)

Hippocampus data collected via fMRI;

-RR words (words that participants remembered well) resulted in a high level of hippocampus activity, along with RK (words participants sort of remembered)

-But after 1 week, when recalling words, there was minimal hippocampus activity for RK words, indicating that the hippocampus was only active for words with a strong episodic component (the ones we remembered well)

-Demonstrates that the hippocampus is constantly involved in retrieval

Sleep Enhances Memory

Gais Experiment; Two groups had to learn 24 pairs of German-English words

Sleep Group - studied the word then slept within 3 hours

Awake Group - studied the word and remained awake for 10 hours

-Sleep group recalled 16 pairs vs just 0.5 pairs recalled by the awake group
Theories on this Effect;

-Sleep eliminates environmental stimuli that might interfere with consolidation

-Sleep might enhance consolidation

-Sleep effect is enhanced if you know you will be tested

Reconsolidation

Process proposed that occurs when a memory is retrieved and so becomes reactivation. Once this occurs, the memory must be consolidated again, as it was during the initial learning; this repeat consolidation is reconsolidation

Nader et Al - Reconsolidation

Condition 1 - Rat receives pairing of tone/shock on day 1, anisomycin is injected to prevent freeze before consolidation. On day 3, rat doesn’t freeze to the tone

Condition 2 - Rat receives pairing of shock/tone on day 1, but no anisomycin until after consolidation. Therefore, it freezes when tone is given on day 3

Condition 3 - Following condition 2, presenting tone on day 2 to reactivate memory, rat freezes then anisomycin is injected. Because the memory was reactivated by the tone, anisomycin now has an effect, rat doesn’t freeze when tone is presented on day 3

-Shows that when reactivated, memory becomes fragile. Therefore, original memory is fragile until it is consolidated for the 1st time, a reactivated memory becomes fragile until it is reconsolidated

Evidence for Reconsolidation in Humans

-Participants learn a list of words but within a specific context

Condition One (Reminder Group) - on day 1, list A comes from a blue bucket. On day 2, list A comes from a blue bucket but a second list is presented from a different object. On day 3, participants tested on list A

Condition Two (No-Reminder Group) - on day 1, list A comes from a blue bucket. On day 2, list A is not presented but list B is presented from a different object. On day 3, participants tested on list A

Condition Two performed the best. When we presented list A and B together (in the Reminder group) it interfered with each other (preventing reconsolidation)

In the No-Reminder group, there was no interference because there was no reactivation, therefore list A was recalled better