Memory

Do we remember from stories our parents tell us or are they genuine?

Why can I remember every detail of what and where I was when I found out John Lennon was shot?

Flashbulb? Short term/long term

Let’s end the mystery!

What is MEMORY?

•Memory – internal record of some prior event or experience; a set of mental processes that receives, encodes, stores, organizes, alters, and retrieves information over time

Three Stages of Memory

• Stage 1Stage 1 - Sensory Memory is a brief representation of a stimulus while being processed in the sensory system

• Stage 2Stage 2 - Short-Term Memory (STM) is working memory– Limited capacity (7 items)– Duration is about 30 seconds

• Stage 3Stage 3 - Long-Term Memory (LTM) is large capacity and long duration

Comparisons of STM & LTM

Comparing STM & LTM

Short term memory Long term memory

Duration

Capacity

Encoding differences

Serial position effect

Brain damage

Short (seconds)

7 + or – 2 (Miller)

Acoustic

Recency effect (last material is better remembered because of interference)

Some patients only lose STM

Long, potentially forever

Unlimited

Semantic

Primacy effect (earlier material is better remembered because it is better rehearsed)

Some patients only lose LTM

Integrated Model Concepts• Encoding – process of

translating info into neural codes (language) that will be retained in memory

• Storage – the process of retaining neural coded info over time

• Retrieval – the process of recovering info from memory storage

Memory Model

Overview of LTMOverview of LTM

Varieties of LTMVarieties of LTM

• Two types of LTM – Semantic memory refers to

factual information – Episodic memory refers to

autobiographical information as to where and when an event happened

Organization of LTM• Retrieval Cue – a clue or

prompt that helps stimulate recall and retrieval of a stored piece of information from long-term memory – 2 types:

1.Recognition2.Recall

1.Ziegarnik Effect - recall ratio for tasks interrupted at the middle or latter end of task completion is higher than for tasks interrupted at or near the beginning.

Memory Measures•Recognition is when a

specific cue (face or name) is matched against LTM

•Recall is when a general cue is used to search memory

•Relearning - situation where person learns material a second time. •Quicker to learn material 2nd

time

Flashbulb Memories

• Memories formed instantaneously and remembered forever, after shocking events

•Where were you when you first heard:–That The WTC had been

crashed into?

Anatomy of Memory

Bilateral damage tothe hippocampus results in anterogradeamnesia (Patient H.M.)

Anatomy of

MemoryAmygdala: emotional memory and memory consolidationBasal ganglia & cerebellum: memory for skills, habits and CC responsesHippocampus: memory recognition, spatial, episodic memory, laying down new declarative long-term memoriesThalamus, formation of new memories and working memoriesCortical Areas: encoding of factual memories, storage of episodic and semantic memories, skill learning, priming.

Forgetting

•Forgetting is the inability to recall previously learned information

Forgetting rate is steep just after learning and then becomes a gradual loss of recall

Serial Position Effect

Recall immediatelyafter learning

Recall several hoursafter learning

Recall from Recall from LTM STM

LTM

Primacy effect – remembering stuff at beginning of list better than middle

Recency Effect – remembering stuff at the end of list better than middle

Study Strategies

• Distributed practice refers to spacing learning periods in contrast to massed practice in which learning is “crammed” into a single session

• Distributed practice leads to better retention

Theories of ForgettingTheories of Forgetting• Proactive interference: old

information interferes with recall of new information

• Retroactive interference: new information interferes with recall of old information

• Decay theory: memory trace fades with time

• Motivated forgetting: involves the loss of painful memories (protective memory loss)

• Retrieval failure: the information is still within LTM, but cannot be recalled because the retrieval cue is absent

Organization of LTM

•Tip-of the tongue phenomenon: person can’t easily recall the item, but shows some recall for its characteristics (“…it begins with the letter ….”)

AmnesiaAmnesia• Amnesia is forgetting produced by

brain injury or by trauma– Retrograde amnesia refers to problems

with recall of information prior to a trauma

– Anterograde amnesia refers to problems with recall of information after a trauma

Point of Trauma

Retrograde amnesiaAnterograde amnesia

Issues in MemoryIssues in Memory•Reasons for inaccuracy of

memory:–Source amnesia: attribution of a

memory to the wrong source (e.g. a dream is recalled as an actual event)

–Sleeper effect: a piece of information from an unreliable source is initially discounted, but is recalled after the source has been forgotten

–Misinformation effect: we incorporate outside information into our own memories

Memory StrategiesMemory Strategies• Mnemonic devices are

strategies to improve memory by organizing information– Method of Loci: ideas are

associated with a place or part of a building

– Peg-Word system: peg words are associated with ideas (e.g. “one is a bun”)

– Word Associations: verbal associations are created for items to be learned