PSY 4 45: Learning & Memory

PSY 445: Learning & Memory Chapter 10: Storage & Retrieval

LTM for naturalistically learned material • Bahrick, Bahrick, & Wittlinger (1975) • Recall • Can you list all your classmates? • Can you name all these faces? • Recognition • Is this the name of a classmate? • Is this the face of a classmate? • Match these names and faces Tested nearly 400 high-school graduates on their ability to recognize and name classmates after delays of up to 30 years.

Permastore Recognition Name Matching Recall Name the picture Bahrick, Bahrick, & Wittlinger (1975) Results were mixed: • Relatively unimpaired: • Ability to recognize their classmates’ faces/names. • Ability to match up names to the appropriate portraits. • Extensively impaired: • Ability to recall a name: 15% for recent grads (33 months) then decline to 7% for the older participants Conclusion: • Recall, but not recognition,of well-learned personal material, closely follows the forgetting curve first demonstrated by Ebbinghaus (1913)

Bahrick, Bahrick, and Wittlinger(1975) Findings • Picture Recognition Test • 50% recall after 34 years • Name Matching Test • 75% recall at 34 years • 60% recall after 47 years • The memory for faces of high school classmates seems quite durable • Forgetting is rather gradual

Remembering Knowledge Learned in School • Semb, Ellis, & Araujo (1993) • Assessed learning 4 and 11 months after a child psychology course • Grades fell only about 20% • MC > Recall • Conway, Cohen, & Stanhope (1991) • Former cognitive psych college students tested up to 12 years after completion of the course • Largest drop occurred with the first 3-4 years; then gradual forgetting afterwards – just like Ebbinghaus

Remembering Knowledge Learned in School • Bahrick (1984) • Tested individuals decades after taking Spanish or algebra • Could tell who got the good grades and who didn’t do so well

Memory for TV shows • Squire & Slater (1975) • MC format of titles of the shows • Recent shows (one to two years) = 70% • Older shows (eight to fifteen years) = 55-60%

Memory for public events • Marslen-Wilson & Teuber (1975) • Older individuals were better at identifying faces from the more recent decades and forgot more of the names from earlier decades

Long-Term retention in animals • Vaughn & Greene (1984) • Pigeons were able to remember discriminative stimuli for food availability up to 730 days

Psychological Models of Semantic Memory • Basic set-up: • Nodes represent concepts in memory • Relations represented links among sets of nodes • Spreading activation Robin Property Wings

Collins & Quillian’s Model (1969) • Spreading activation • Activation is the arousal level of a node • Spreads down links • Used to extract information from network

Collins & Quillian’s Model (1969) • Structure is hierarchical • Time to retrieve information based on number of links • Inheritance • Lower-level items also share properties of higher level items

Collins & Quillian’s Model (1969) Has skin Animal Breathes Eats Has fur Has fins Fish Dog barks swim 4 legs Has gills Is pink Has spots Dalmatian Skinny tail Salmon Is edible Black & white Lays eggs upstream

Collins & Quillian Model (1969) • Support • Collins & Quillian (1969) serial reaction time (SRT) experiment • Criticism • Some violations in SRT experiments • Does not explain the typicality effect

Models of Semantic Memory • Collins & Quillian (1969) • Evidence: When people do a semantic verification task, you see evidence of a hierarchy (response times are correlated with the number of links)

Models of Semantic Memory • Problems with network models: • With the hierarchy: “A horse is an animal” is faster than “A horse is a mammal” which violates the hierarchy • A chicken is more typical of animal than a robin, a robin is more typical of bird than a chicken. • How can a network account for this?

Models of Semantic Memory • Problems with network models: • Answering “no”: You know the answer to a questions is “no” (e.g., “a bird has four legs”) because the concepts are far apart in the network. But, some “no” responses are really fast (e.g., “a bird is a fish”) and some are really slow (e.g., “a whale is a fish”). The reason for this isn’t obvious in the model

Problems with network models • Does not explain the typicality effect

Typicality Effect • Statements about prototypical objects are verified quickly. • Is an apple a fruit?  Yes/No • Is pomegranate a fruit?  Yes/No Smith et al. (1974)

Collins & Loftus (1975) Semantic Model • Got rid of hierarchy • Allowed links to vary in length to account for typicality effects See Next Slide 

Collins & Loftus (1975) swims fish 4 legs fur Goldie dog pet Lucy mutt poodle

Neuropsychological Dissociations • A modular approach suggests that there are hypothetically separate memory modules in the brain, each underlying different sorts of knowledge • Caramazza & Hillis (1991) • Two patients were impaired at verb production • One had problem with reading; the other with writing to dictation • Verbs would be mispronounced; misspelled, misread, or go unrecognized as words • Presented homonyms • Patients could read word when it was a noun but not as a verb • “There was a crack in the mirror”– no problem • “Don’t crack the nuts in here” – could not read this

Duchaine, Yovel, Butterworth, & Nakayama (2006) • Case study: Edward: • Lifelong face recognition difficulties (prosopagnosia) • Also problems with expression perception • No navigational difficulties

Edward's profile of impairment: Face naming test (black = Edward, grey = control participants) Face naming test (black = Edward, grey = control participants)

Detection test: Edward 91.2% correct, controls 87.2% (unimpaired) Face naming test (black = Edward, grey = control participants) Face detection test: Edward 91.2% correct, controls 87.2% (i.e. unimpaired)

Face naming test (black = Edward, grey = control participants) Face detection test: Edward 91.2% correct, controls 87.2% (i.e. unimpaired) Old/new discrimination test: black = Edward, (a) relative to average control performance, (b) in relation to individual control performances.

Greebles: computer-generized beings greeble-learning abilities. Implies greebles are learnt using object-recognition systems, not face-processing mechanisms. Face vs. body recognition

Edward's profile of impairment and its implications: Fairly specific problems with face recognition and emotion recognition. Normal-range performance with inverted faces and headless bodies shows he has no problems with low-level pattern recognition (e.g. curvature discrimination) or within-class discrimination generally. Normal second-order configural processing for houses but not faces - so no generalconfigural deficit. Deficit seems to be at the structural encoding stage of face processing. Duchaine et al. (2006): suggest Edward failed to develop a face-specific processing mechanism; this did not affect other object-recognition systems.

Biological Substrates • Engram • Neural representation of the brain • Ongoing search in the field of learning and memory • Theories: • Memory-molecule theory • Synaptic connection theory • Long-term potential

Biological Substrates • Memory-Molecule Theory • Much evidence that biochemical changes occur during the brain during learning • This theory posits that a unique memory molecule is formed that encodes each new experience • Early hopes that we could develop a “knowledge pill” have faded • Early support for this theory have faded as well

Biological Substrates • Synaptic Connection Theory • Much evidence that the number of synaptic connections between neurons is not fixed but is affected by life experiences • Long-term potential in hippocampal cells may lead to better memory • This theory posits that: repetitive stimulation in one cell (or a set of cells) enhances the capacity for adjacent cells to be triggered • Spreading activation occurs from one cell to another • Repeated experience allows activation of one cell by another to occur more readily • One stimulus cues another as in classical conditioning, paired-associate learning, and cued recall

Synaptic Connection Theory • Kandel (2001) • Found evidence for two storage process: STM, LTM • Synaptic changes seen that underlie learning in a marine snail (Aplysia) • Long-term potentiation also seen in experiments on mice • Transient chemical changes occur at the synapses that allow subsequent stimuli to trigger nerve impulses • This process lasts for hours • Repeated intense stimulation leads to chemical changes in the synapse, coding in the nucleus of the cell and the growth of additional connections between cells • These final changes are the ones that characterize consolidation and the formation of durable LTM

Consolidation Theory • Memories start off in temporary from and over time become consolidated into a more permanent form • Reverberation can occur • The initial STM’s might be retained in the brain in one form (possibly in the persisting activity of recently triggered nerve cells) • These transient memories are susceptible to disruption or interference which can block their consolidation into permanent memory • LTM might be encoded by structural changes that occur at the synapses • The consolidated memories are more resistant to loss, change, or interference

Consolidation Theory • This theory posits that when learning occurs it can be demonstrated immediately after the learning experience • However, the memory is in an unconsolidated state (STM processes) which will decay and be forgotten unless consolidated into permanent memory

Testing for Consolidation • Consolidation Blocking Experiments • Electroconvulsive shock (ECS) • Given shortly after a learning trial prevents retention of that learning • Protein-Synthesis Inhibitors • These drugs inhibit metabolic behavior in the brain shortly after the learning trial • The normal chemical activities that could possibly have consolidated a fresh memory are blocked; permanent memory is not possible

Retrieval from Episodic Memory • Distinctiveness • Retrieval cues may be uniquely targeting a single memory • Flashbulb memories • Von Restorff effect • Testing Effects • Retrieval is facilitated by previous retrieval • Improvement in recall performance arising from repeated testing sessions on the same material • Increases with more recall tests • Largest effects on free recall, but also appears for cued recall and recognition • Doesn’t fit in with forgetting paradigm See Next Slide 

Testing Effects Erdelyi&Kleinbard (1978) Procedure Studied 60 object line drawings (pictured objects such as DOG, CAT, or TREE) Only one study period but then tested 20 times Repeatedly tried recalling the pictured objects

Testing Effects Erdelyi & Kleinbard (1978) Results Recall improved over testing days Essentially reversed Ebbinghaus’s forgetting curve Larger effects for pictures than for less-imaginable words Conclusion Hypermnesia arises through visualization and reconstruction

Hypermnesia in Everyday Life • Bluck, Levine, &Laulhere (1999) • Procedure • Asked people who had viewed the televised OJ Simpson verdict 8 months prior to recall details about the event • Participants were interviewed three times in a row • Results • The number of verifiable details remembered increased over the interviews, revealing hypermnesia • Verifiable details went from 27% to 52% with no notable increase in % of false alarms

What makes a good retrieval cue? • Associations • Encoding Specificity • Contextual Learning • State-Dependent Learning • Mood-Dependent Recall

Associations • Effective retrieval cues include those that are connected to the target by strong associations • Mantyla (1986) • Procedure • Acquisition Phase • Participants studied 600 words; as each word was presented, participants were asked to generate up to three properties that described the word • Test Phase • Either the self-generated one-word descriptors or someone else’s cues were supplied to the participant when attempting to recall a particular word • Note: Total time for both phases was 6 hours (one session)

Associations • Mantyla (1986) • Results • Immediate Recall Test: • 90% recall with own words • 20% recall with someone else’s words • One-Week Delayed Recall Test: • Approximately 65% recall with own words • 20% recall with someone else’s words

Encoding Specificity • Tulving & Thomson (1973) • Theoretical interpretation of relationship between info at encoding and cue at retrieval • Specific encoding operations determine what is stored, and what is stored determines what retrieval cues are effective in providing access to it • Recognition occurs when the memory test reactivates the same meaning with which target words had been encoded (during acquisition)

Encoding Specificity Principle • Specific encoding operations determine what is stored, and what is stored determines what retrieval cues are effective in providing access to it • -> leaves room for uniqueness of encoding in • different individuals (subjective encoding) • -> benefits of cues for retrieval may vary from • individual to individual

Encoding-Specificity Principle • specific encoding operations determine what is stored, and what is stored determines what retrieval cues are effective in providing access to it • problem for empirical research: • how do we know what person encodes in the first place (in terms of experience)? • -> can we ever distinguish between loss of access vs. loss of availability (retrieval failure vs. true forgetting) ? • Schacter: probably not at cognitive level, • in principle yes at neural level

Contextual Learning • Recall is better if the retrieval context is similar to the encoding context • Déjà vu Effect See next two slides 

Godden & Baddeley (1975)

Grant et. al (1998)

State Dependent Learning • Memory is better when a person’s internal state during retrieval matches their internal state during encoding • Information learned in the same drug-influenced state leads to better memory

Mood Dependent Recall • Moods Cue • Memory is better when a person’s internal state during retrieval matches their internal state during encoding • Information learned in a particular emotional state (e.g., depressed, happy, etc.) may be more easily recalled when in that same state of mind Murray et al. (1999) Mood congruence See next slide 

PSY 4 45: Learning & Memory