Multiple Forms of Memory?

• Memory for short periods of time seems to be different than memory for longer periods Memory of time • Brain damage can disrupt some kinds of memory but leave other kinds unaffected. Intro Psychology • Some things seem easy to remember and Georgia Tech some things really difficult. Instructor: Dr. Bruce Walker

Episodic Buffer Donald O. Hebb Visual Cache DiagrInanerm • Reverberations of Scribe neural activity store Inner Speech information for short periods

Visual Cache Inner Scribe

Innerr Speech

PERCEPTION • Strengthening of connections between activated neurons store information over PERCEPTION the long term (Hebbian Learning)

Temporal Distinctions in Memory Temporal Distinctions in Memory

• Retention of • Over time, information over short hippocampus periods of time appears to become depends on specific less important. brain regions. • Memories become more dependent on • Hippocampus and cortical areas, less surrounding cortex on hippocampal regions

1 Damage to Hippocampus and Learning Lists of Words Associated Areas. • Present a list of words • After presentation, a signal to recall is given Hippocampus nearby areas - quick acquisition of information. and subjects attempt to recall as many as - Can’t store the information forever. possible. • Plot the probability of recall for words as a Cortical areas function of their position in the list (serial - slow acquisition of information. position) - much longer term storage.

Barbara Bush Serial Position Curve Peter Smith Bill Kingstone Recency Effect Kate Moss List Length 20 List Length 30 List Length 40

P 100 e

Susan Sarandon r c

e 80

n Primacy Effect

Warren Albert t a

g 60 e

Shelby White R 40 e

Danielle Steele c a l Linda Hamilton l 20 0 Olaf Meyer 4 8 12 16 20 24 28 32 36 40 Bart Kiele Serial Position Emily Dickinson Oscar Blanc Murdock (1962)

Working Memory Phonological Loop

• “A system for temporarily holding and • Phonological loop functions very similar to manipulating information as part of a wide overt speech range of essential cognitive tasks such as • Subjects can generally remember about as learning, reasoning, and comprehending” many words as they can say in 2 seconds.

Baddeley (1990) • Is this meaningful? – Is memory span influenced by speaking rate?

2 Phonological Loop - Mental Rehearsal Phonological Loop

• Phonological Similarity Word Length 1 Z L Q N K S J Effect: 2 P B V C T D G Longer words take – Note: 2 is more difficult than 1 longer to say, shorter memory span. • Word Length 1 bus clock spoon fish 2 refrigerator hippopotamus …. 3 Friday Typhoon versus Cricket Wicket

Phonological Loop Phonological Loop

Word Length Effect: As children get older, overt speaking rate Also, memory span increases and this for 2 syllable, long tracks closely to words (e.g., their increase in memory furlough) is less span. than for 2 syllable short words (e.g., bishop)

Visuospatial Memory Proactive Interference

• Not quite as nicely developed • Previous items interfere with current memory set. • Some interesting analogies with the phonological loop but just not much • Previous items are confused with current memory set, and they are more likely to be research. recalled.

• Definitely seems to be something different • Reduce interference by making items more distinct?

3 What does all of this research Release from Proactive Interference suggest?

• Wickens (1972) • Similarity is bad – causes interference – Presented FRUITS for

first 3 trials 100

– Either switch (75%) or Professions continue with same. 80 • Distinctiveness helps make individual Flowers – Big increase in 60 memories easier to recall. performance on 4th trial with switch. 40 Vegetables Percentage

– Amount of increase 20 inversely related to Fruits (control)

similarity Recall 0 1 2 3 4 Trial Number

Encoding Specificity Encoding Specificity

• What kinds of things serve as cues? • What kinds of things serve as cues? Godden & Baddeley (1975) Godden & Baddeley (1975) Memory capacity of deep sea divers. Learn lists of words:

Percent of w 50 On the beach Words learned on land. Under 15 feet of water. 40 Tested: 30 ords recalled On the beach 20 Words learned Under 15 feet of water. 10 underwater

0 Recalled on Recalled Land Underwater

State Dependency Getting Stuff in for the Long Haul

• Recall is better when individuals are in the same emotional and physical state as they • Hyde & Jenkins (1973) were in during learning. – Presented a list of words Test – 3 Different Instructions: Ordinary Marijuana Study words for a later memory test Study Cigarette Cigarette Average Rate the Pleasantness of the words (not told of any test) Ordinary Cigarette 25% 20% 23% Count the number of letters in the word Marijuana Cigarette 12% 23% 18% – What is the effect of processing words on later memory performance? Eich (1975)

4 Getting Stuff in for the Long Haul Levels of Processing

• Hyde & Jenkins (1973) • Craik and Lockhart, U of Toronto – Any perceived stimulus is processed Intentional Learning - 69% of words recalled – Stimuli may be processed at an incidental, “shallow” level. (e.g., maintenance rehearsal using the phonological loop) Incidental Learning - Pleasantness, 68% – Alternatively processing may be intentional, Incidental Learning - Count letters, 39% focused on meaning. – Deeper gives better memory performance than shallow.

Levels of Processing Levels of Processing

• Craik & Tulving (1975) • Craik & Tulving (1975)

Answer questions about words Answer questions about words – Recognition • Semantic: “Is the word a type of fish? – SHARK” results • Rhyme: “Does the word rhyme with park – SHARK” • Semantic: 73% • Orthographic: “Does the word start with S – SHARK” • Rhyme: 56% • Orthographic: 17% (note: these scores are corrected Hits – False alarms, chance performance is 0%)

False Recall False Recall

• Remember versus Know Judgements low hill thread clouds valley pin – Roediger & McDermott asked subjects if they: up climb eye tall summit sewing tower top sharp Remember: Items for which they have a vivid jump molehill point above peak prick memory of the actual presentation building plain thimble noon glacier haystack Know: items that they were sure had been cliff goat thorn presented but for which they lacked specifics. sky bike hurt over climber injection airplane range syringe dive steep cloth elevate ski knitting

5 Memory Distortions

• Elisabeth Loftus (1974) – Students viewed films depicting vehicle accidents. – After each film, students asked to give an account of the accident they just saw. – Questions were asked to elicit additional information.

Memory Distortions Memory Distortions

• Elisabeth Loftus (1974) • Elisabeth Loftus (1974) – “How fast where the cars going when they ______each other?” Verb Mean Speed Estimate • “hit”, “smashed into”, “collided with”, “bumped”, “contacted” Smashed 40.8 Collided 39.3 – Later question asked students to report the Bumped 38.1 speed of the car. Hit 34.0 Contacted 31.8

Memory Distortions Memory Distortions

• Elisabeth Loftus (1974) • Loftus & Coan (1993) – One week later, students were asked if they Participants read detailed descriptions of four saw broken glass (no films showed any broken events. glass) 3 events were actually from their childhood, 1 event (being lost in a shopping mall) had never – 32% of “smashed” students said yes occurred. – 14% of “hit” students said yes

6 Memory Distortions Memory Distortions

• Loftus & Coan (1993) • Loftus & Coan (1993) 2 weeks later, 25% of participants reported high “I was with you guys for a second and I think I levels of confidence in their memory of being went over to the toy store, the Kay-bee toy and lost. uh, I got lost and I was looking around and I thought “Uh-oh. I’m never going to see my family again. I was really scared you know. And then this old man, I think he was wearing blue flannel, came up to me. … he was kind of old. He was bald on top…”

Eye Witness Testimony The Sleeper Effect

• Information from low credible source is rated as having low credibility. • Over time, the source of the information is lost, and the information becomes rated as more credible.

• In other words, lose details like source, but we keep enough information to be misled.

Mere Exposure Memory Distortions

“Because you see,” says Bloom, “for an advertisement you must have repetition. That’s the whole secret.” • Memory reports are combinations of James Joyce from Ulysses Information from original event Person’s background knowledge and schemas (Bartlett) Bob Zajonc, Stanford University Information presented after the event Simple repetition of a stimulus can • Implications result in a shift in preference toward the repeated stimulus. – Accuracy of eye witness testimony – Identification of criminals from photos or a lineup. – Recovered memories

7 What function is served by What function is served by having two types of memory? having two types of memory? • Similarity is bad. • Semantic similarity is bad if you want very specific information

• Similarity is good. • Semantic similarity is good if you want to acquire and retain useful, general knowledge.

What function is served by But let’s not go overboard having two types of memory? • Hippocampus and surrounding structures • Imagine a library with limited money, people, and space. – Fast acquisition of information – little overlap in representations to help reduce • To save money, it is decided to remove interference books that are not useful for students and • Cortical Brain Areas faculty. – Slower acquisition of information • How do you identify those books? – highly overlapping representations to allow generalization

8