Memory processes

Memory Processes

Chapter 6

Outline

1. Encoding and Transfer of Information

2. Retrieval

3. Processes of Forgetting and Memory Distortion

4. The Constructive Nature of Memory


1. Forms of Encoding Short-Term Storage

• Acoustic Encoding– Participants were presented with series of

six letters in a serial-recall task– Errors – participants substituted letters that

sounded like the correct letters (e.g. B for P)– Short-term memory relies primarily on an

acoustic rather than semantic or visual code


1. Forms of Encoding Short-Term Storage

• Semantic Encoding (by meanings of words)– Although encoding in short-term memory appears to

be primarily acoustic, there may be some secondary semantic encoding as well

• Visual Encoding– We sometimes temporarily encode information

visually as well, although visual encoding appears to be more fleeting and vulnerable to decay than acoustic encoding


1. Forms of Encoding Long-Term Storage

• Semantic Encoding– Most information stored in long-term

memory is primarily semantically encoded– Evidence

• In recognition tasks participants make more errors when distracters are semantically related to target words

• We have tendency to remember words by clustering them into categories (e.g. animals)


1. Forms of Encoding

Long-Term Storage

• Visual Encoding– We tend to cluster items into categories

according to their visual similarities

• Acoustic Encoding– Sometimes (even though rarely) we use

acoustic encoding too


2. Transfer of Information from Short-Term Memory to Long-Term Memory

• Basic Concepts– Consolidation

• Process of integrating new information into stored information

– Metamemory Strategies• Based on reflecting on our own memory processes

wit a view to improving our memory



• Rehearsal– Repeated recitation of an item– To move information into long-term memory, an

individual must engage in elaborative rehearsal, in which the person meaningfully integrates the items into what the person already knows

– Maintenance rehearsal – the person simply repetitiously rehearses the items to be repeated, temporarily maintains information in short-term memory without transferring it to long-term memory



• Spacing effect– People tend to remember information longer when they

acquire it via distributed practice (i.e., various sessions spaced over time) rather than via massed practice (session crammed together all at once)

– A good night’s sleep, which includes plenty of REM stage sleep, aids in memory consolidation

– Benefits of distributed practice seem to occur because we have a relatively rapid learning system in the hippocampus that becomes activated during REM sleep



Mnemonic devices• Specific techniques to help you memorize lists of

words by adding meaning to otherwise meaningless lists of items

1. Categorical clustering– One organizes a list of items into a set of categories

(e.g. fruits, vegetables,…)2. Interactive images

– One imagines the objects represented by words one has to remember interacting with each other in some active way



Mnemonic devices (cont.)3. Pegword system

– One associates each word with a word on a previously memorized list and forms and interactive image between the two words (e.g. “one is a bun,” “two is a shoe” – imagining an apple between two bunds a sock stuffed inside a shoe)

4. Method of loci– One visualizes walking around an area with distinctive

landmarks and one then links the various landmarks to specific items to be remembered (e.g. a strange-looking house with a sock on top of the house in place of the chimney)



Mnemonic devices (cont.)

5. Acronyms– One devises a word or expression in which each of its

letters stands for a certain other word or concept (e.g. UK)

6. Acrostics– One forms a sentence rather than a single word to help

one remember new words (e.g. “every good does fine” to recall names of notes in music)



Mnemonic devices (cont.)

7. Keyword system– One forms an interactive image that links the sound

and meaning of a foreign word with the sound and meaning of a familiar word (e.g. libro (Spanish) with liberty and think of the Statue of Liberty holding up a large book)

2. Retrieval

1. Retrieval from Short-Term Memory

• Saul Sternberg (1966)– Wondered whether items are retrieved all at

once (parallel processing) or sequentially (serial processing)

– See his paradigm on the next slide

?

Memorize the following list of numbers:

6, 3, 8, 2, 7, 5

Was 8 on the list?

2. Retrieval

1. Retrieval from Short-Term Memory• Saul Sternberg (1966)

– Parallel processing• Simultaneous handling of multiple operations• Response times should be the same, regardless of

the size of the set of items, because all comparisons would be done at once

– Serial processing• Operations being done one after another• It should take longer to retrieve four digits than to

retrieve two digits

2. Retrieval


• Saul Sternberg (1966)– Serial processing

• Exhaustive serial processing – the participant always checks the test digit against all digits in the set, even if a mach were found partway through the list

• Self-terminating serial processing – the participant would check the test digit against only those digits needed to make a response

2. Retrieval


• Saul Sternberg (1966)– Results

• Response times increased linearly with set size but were the same regardless of serial position

• It indicates that serial exhaustive model seems to be right

2. Retrieval

2. Retrieval from Long-Term Memory

• Categorization dramatically affects retrieval– Cued-recall (participants tested category by category)

is far better than free-recall (participants recalled as many words as they could regardless of the category)

– Participants given hierarchical presentation of categories of items recalled 65% of words, compared with recall of just 19% by participants given the words in random order

3. Processes of Forgetting and Memory Distortion1. Interference theory

• Competing information causes us to forget something

• “Brown-Peterson” paradigm (Brown and Peterson, 1959)– Participants had to recall trigrams (strings of three

letters) at intervals of 3, 6, 9, 12, 15, or 18 seconds after the presentation of the last letter

– After oral presentation of each trigram, participants were asked to count backward by threes from a three-digit number spoken immediately after the trigram

3. Processes of Forgetting and Memory Distortion1. Interference theory

• Two kinds of interference– Retroactive interference

• Caused by activity occurring after we learn something but before we are asked to recall that thing

• The interference in the Brown-Peterson task appears to be retroactive because counting backward by threes occurs after learning of the trigram and interferes with our ability to remember information we learned previously

– Proactive interference• The interference material occurs before, rather than after,

learning of the to-be-remembered material• In the Brown-Peterson task the trigrams learned earlier

interfered with participants’ ability to remember later trigrams

?

Say the following list of words once to yourself, and then, immediately thereafter,

try to recall all the words, in any order, without looking back at them:

Table, cloud, book, tree, shirt, cat, light, bench, chalk, flower, watch, bat, rug, soap,

pillow

3. Processes of Forgetting and Memory Distortion

Recency and primacy effects• Recency effect

– Superior recall of words at and near the end of the list – Words at the end are subject to proactive but not

retroactive interference

• Primacy effect– Superior recall of words at and near the beginning of

the list– Words at the beginning of the list are subject to

retroactive but not proactive interference– Words in the middle of the list are subject to both

types of interference, therefore, recall is poorest in the middle of the list

3. Processes of Forgetting and Memory Distortion2. Decay theory

• Information is forgotten because of gradual disappearance, rather than displacement, of the memory trace

• It is exceedingly difficult to test – Preventing participants from rehearsing and

ruling out the interference at the same time is difficult

– Possibility: visually present participants with words and then engage them in a tone-detection task


• Memory retrieval is not just reconstructive– Involving the use of various strategies for retrieving

the original memory traces of our experiences and then rebuilding the original experiences as a basis for retrieval

• Memory retrieval is also constructive – Prior experience affects how we recall things and

what we actually recall• Participants read an ambiguous passage that could be

interpreted meaningfully as being either about watching a peace march or about a space trip

• Participants omitted different details, depending on what they thought the passage was about


Autobiographical memory

• Refers to memory of an individual’s history

• It is constructive– One does not remember exactly what has

happened– Rather, one remembers one’s construction or

reconstruction of what happened– It is differentially good for different periods of

time


Memory Distortions• Seven specific ways in which distortions occur:

– Transience: memory fades quickly– Absent-mindedness: people sometimes brush their

teeth after already having brushed them– Blocking: people have something that they know they

should remember, but they can’t– Misattribution: People often cannot remember where

they heard what they heard– Suggestibility: people are susceptible to suggestion– Bias: People often are biased in their recall (e.g. pain)– Persistence: People sometimes remember personally

significant but inconsequential things (e.g. single failure on an exam)


Eyewitness Testimony– Experiments have shown people’s great

susceptibility to distortion in eyewitness accounts

– Problems with wrongful conviction when using eyewitness testimony

– Lineups can lead to faulty conclusions– It is clearly suspect in children because they

are highly susceptible to suggestive questioning


• Repressed Memories– No compelling evidence points to the existence of

such memories

• Context Effects on Encoding and Retrieval– Flashbulb memory

• Memory of an event so powerful that the person remembers the event as vividly as if it were preserved on film

– We remember better event with significant emotional intensity

– When information is encoded in various contexts, the information also seems to be retrieved more readily in various contexts

Memory processes

Art & Photos

transfer of information

memory distortion

new information

p shortterm memory

secondary semantic encoding

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memory processes chapter

constructive nature