Memory and Cognition PSY 324 Topic: Long-term Memory- Encoding and Retrieval Dr. Ellen Campana Arizona State University

Storage of Memories Information is used in one type of memory system (STM / WM) but in order for it to stick around for longer than a few seconds it needs to be transferred into Long-term Memory Information is used in one type of memory system (STM / WM) but in order for it to stick around for longer than a few seconds it needs to be transferred into Long-term Memory Transferring information TO LTM is called encoding or storage Transferring information TO LTM is called encoding or storage Vocabulary note: Vocabulary note: Coding refers to the form in which information is represented Coding refers to the form in which information is represented Encoding refers to the process used to get information into LTM Encoding refers to the process used to get information into LTM Transferring information OUT OF LTM in order to use it in STM/WM is called retrieval Transferring information OUT OF LTM in order to use it in STM/WM is called retrieval

Rehearsal We saw last chapter that in certain cases simply repeating information can cause it to be stored We saw last chapter that in certain cases simply repeating information can cause it to be stored What affect showed this in the last class??? What affect showed this in the last class??? Simply repeating information is called maintenance rehearsal because it is most useful for keeping the information in STM/WM Simply repeating information is called maintenance rehearsal because it is most useful for keeping the information in STM/WM Maintenance rehearsal is actually NOT an effective way to transfer information to LTM Maintenance rehearsal is actually NOT an effective way to transfer information to LTM A more effective way to encode information is through elaborative rehearsal – making connections between the new item and memories you already have A more effective way to encode information is through elaborative rehearsal – making connections between the new item and memories you already have Does this sound familiar? What concept is like this in STM? Does this sound familiar? What concept is like this in STM? Levels of Processing Theory explains these differences Levels of Processing Theory explains these differences

Levels of Processing Theory (Craik & Lockhart, 1972) Basic idea: memory depends on the specific process used to get information into LTM Basic idea: memory depends on the specific process used to get information into LTM Shallow processing: little attention to meaning, based on surface characteristics Shallow processing: little attention to meaning, based on surface characteristics Count the vowels Count the vowels Deep processing: considering meaning and/or relating items to other information in LTM Deep processing: considering meaning and/or relating items to other information in LTM Think about how useful it would be on a desert island Think about how useful it would be on a desert island Try the demo on page 198 (takes too long for class) Try the demo on page 198 (takes too long for class) Confirmed in many different studies of memory for words, but two levels turned out to be too simple Confirmed in many different studies of memory for words, but two levels turned out to be too simple

Levels of Processing Craik & Tulving (1975) introduced more levels Craik & Tulving (1975) introduced more levels Shallow: A question about the physical features Shallow: A question about the physical features Is the word printed in capital letters? [bird] Is the word printed in capital letters? [bird] Deeper: A question about rhyming Deeper: A question about rhyming Does the word rhyme with train? [pain] Does the word rhyme with train? [pain] Deepest: A fill-in-the-blanks question Deepest: A fill-in-the-blanks question Does the word fit in the sentence “he saw a ___ on the street”? [car] Does the word fit in the sentence “he saw a ___ on the street”? [car]

Levels of Processing % of words recalled after delay Fill-in- the- blanks RhymeCapital Letters

Levels of Processing Are you convinced? Are you convinced? People were, at first. But then a bunch of new tasks were tried and a people discovered a circularity in the argument People were, at first. But then a bunch of new tasks were tried and a people discovered a circularity in the argument What makes a level “deep”? It leads to better memory. What makes a level “deep”? It leads to better memory. And why care about “depth”? It can predict memory. And why care about “depth”? It can predict memory. Dissatisfaction with the Levels of Processing Theory coincided with introduction of a new theory about the encoding of long-term memory: Transfer-Appropriate Processing Dissatisfaction with the Levels of Processing Theory coincided with introduction of a new theory about the encoding of long-term memory: Transfer-Appropriate Processing

Transfer-Appropriate Processing Basic idea: memory is best when the task at encoding matches the task at retrieval Basic idea: memory is best when the task at encoding matches the task at retrieval Morris and Coworkers (1977) independently varied the tasks at encoding and retrieval Morris and Coworkers (1977) independently varied the tasks at encoding and retrieval Encoding tasks: meaning-task (fill-in-the-blanks) and rhyming-task Encoding tasks: meaning-task (fill-in-the-blanks) and rhyming-task Retreival tasks: standard recognition task and rhymed recognition task (does it rhyme with a word you heard?) Retreival tasks: standard recognition task and rhymed recognition task (does it rhyme with a word you heard?)

Transfer-Appropriate Processing Fill-in- the- blanks Rhyme % correct Standard Recognition Test Rhymed Recognition Test Matching

Other factors that aid encoding NOTE: All of these are about encoding, but caused by increasing retrieval cues NOTE: All of these are about encoding, but caused by increasing retrieval cues Forming connections with other information Forming connections with other information More vivid /detailed => better memory More vivid /detailed => better memory Visually imagining pairs of words => better memory Visually imagining pairs of words => better memory Bower & Wizenz (1970) Bower & Wizenz (1970) Self-reference effect Self-reference effect Rogers and Coworkers (1979) Rogers and Coworkers (1979)

Other factors that aid encoding Generating information Generating information The generation effect (Slameka and Graf, 1978) The generation effect (Slameka and Graf, 1978) Read (king-crown) vs fill-ins (king-cr_____) Read (king-crown) vs fill-ins (king-cr_____) Memory for words that were filled in is better Memory for words that were filled in is better Organizing information Organizing information Bower and colleagues –similar groupings Bower and colleagues –similar groupings Bransford and Johnson – balloon picture study Bransford and Johnson – balloon picture study

Encoding Specificity Basic idea: Context of learning (location, etc.) can act as a retrieval cue Basic idea: Context of learning (location, etc.) can act as a retrieval cue It’s actually good for you that we’re using scan-tron! It’s actually good for you that we’re using scan-tron! Diver Study (who?) Diver Study (who?) Group of divers Group of divers ½ learned a list on land ½ learned a list on land ½ learned a list under water ½ learned a list under water ½ tested on land ½ tested on land ½ tested under water ½ tested under water

State-Dependent Learning Basic idea: Your own internal state can act as a retrieval cue Basic idea: Your own internal state can act as a retrieval cue Emotions, sleep-deprivation state, chemicals Emotions, sleep-deprivation state, chemicals

How Long-term Memories are Stored (biologically-speaking)

Storage at the Synapse Remember Chapter 2, discussion of faces? Remember Chapter 2, discussion of faces?

Storage at the Synapse Representation of each face is a memory Representation of each face is a memory How did these particular memories come to be represented by these particular neurons firing in this pattern? How did these particular memories come to be represented by these particular neurons firing in this pattern? Key is in the synapses between neurons Key is in the synapses between neurons Neurotransmitters cause structural changes Neurotransmitters cause structural changes Structural changes modify the firing rate of neurons Structural changes modify the firing rate of neurons Hebbian Learning, Long-term Potentiation Hebbian Learning, Long-term Potentiation “Neurons that fire together, wire together” “Neurons that fire together, wire together”

Structure of a Neuron

Storage at the Synapse

Process of Long-term Potentiation Process of Long-term Potentiation A and B are connected such that A’s axon synapses with B’s dendrite A and B are connected such that A’s axon synapses with B’s dendrite Both A and B may be connected to many other neurons Both A and B may be connected to many other neurons When A and B fire at the same time, neurotransmitters cause structural changes When A and B fire at the same time, neurotransmitters cause structural changes Effect is that over time the same stimulus will produce faster firing rates by B Effect is that over time the same stimulus will produce faster firing rates by B Hebb came up with this in 1948, but neurological evidence came much later Hebb came up with this in 1948, but neurological evidence came much later Important because it is used in connectionist models Important because it is used in connectionist models

Fragility of New Memories Much evidence that new memories are fragile Much evidence that new memories are fragile Concussions – memory for events just prior is lost Concussions – memory for events just prior is lost Electroconvulsive Therapy – again, memory for events just prior is lost (at least temporarily) Electroconvulsive Therapy – again, memory for events just prior is lost (at least temporarily) Another dimension of amnesia Another dimension of amnesia Retrograde amnesia – loss of declarative memory for events prior to a trauma Retrograde amnesia – loss of declarative memory for events prior to a trauma Graded amnesia – loss worse for more recent memories Graded amnesia – loss worse for more recent memories Anterograde amnesia – inability to form new memories Anterograde amnesia – inability to form new memories

Graded Amnesia H.M. in your book (had hippocampus removed) H.M. in your book (had hippocampus removed) Had both retrograde and anterograde amnesia Had both retrograde and anterograde amnesia His retrograde amnesia was graded His retrograde amnesia was graded Could remember events before 10-15yrs before operation Could remember events before 10-15yrs before operation More recent memories, more damage More recent memories, more damage PAST FUTURE Old memories have graded damage Operation New memories are never even formed

Graded Amnesia Why talk about graded amnesia right now? Why talk about graded amnesia right now? Demonstrates that recent memories are more fragile Demonstrates that recent memories are more fragile Some process must make memories less fragile Some process must make memories less fragile Hippocampus involved in recent (not old) memories Hippocampus involved in recent (not old) memories That’s because H.M. had no hippocampus That’s because H.M. had no hippocampus Consolidation is the process that makes memories less fragile over time Consolidation is the process that makes memories less fragile over time Synaptic consolidation Synaptic consolidation Systems consolidation Systems consolidation

Process of Consolidation Synaptic consolidation Synaptic consolidation First type to be studied First type to be studied Rapid, happens over the time span of minutes Rapid, happens over the time span of minutes Long-term Potentiation is an example Long-term Potentiation is an example Systems consolidation Systems consolidation Large-scale reorganization of circuits of neurons Large-scale reorganization of circuits of neurons Gradual, happens over days, weeks, months, years Gradual, happens over days, weeks, months, years Standard model of consolidation Standard model of consolidation Retrieval depends on hippocampus during consolidation Retrieval depends on hippocampus during consolidation Afterwards, hippocampus no longer involved Afterwards, hippocampus no longer involved

Standard Model of Consolidation Early on, memory is distributed across the brain, no connections between active cortical areas Early on, memory is distributed across the brain, no connections between active cortical areas Sights, sounds, smells, etc. Sights, sounds, smells, etc. Hippocampus coordinates activity across the cortical area during memory reactivation Hippocampus coordinates activity across the cortical area during memory reactivation Links form between active cortical areas Links form between active cortical areas Gradually the hippocampus is no longer involved in retrieval Gradually the hippocampus is no longer involved in retrieval

Standard Model of Consolidation

Much of consolidation (including reactivation) happens during sleep / relaxed wakefulness Much of consolidation (including reactivation) happens during sleep / relaxed wakefulness Can also happen during rehearsal Can also happen during rehearsal Especially elaborative rehearsal Especially elaborative rehearsal Results in situation where only cortical activity is necessary for remote memories Results in situation where only cortical activity is necessary for remote memories Remote memories are memories for events that occurred long ago Remote memories are memories for events that occurred long ago

Consolidation Controversy That’s the nice clean model… but there is controversy about the claim that the hippocampus completely drops out of retrieval That’s the nice clean model… but there is controversy about the claim that the hippocampus completely drops out of retrieval Evidence for no hippocampal involvement Evidence for no hippocampal involvement Brain imaging – Medial Temporal Lobe (which contains the hippocampus) is not active for remote memories Brain imaging – Medial Temporal Lobe (which contains the hippocampus) is not active for remote memories Used semantic, not episodic, memories Used semantic, not episodic, memories Evidence for hippocampal involvement Evidence for hippocampal involvement Brain imaging studies looking at episodic memories Brain imaging studies looking at episodic memories

Test Reminders

Studying for Tests Elaborate and Generate – why? Elaborate and Generate – why? Organize – why? Organize – why? Associate – why? Associate – why? Take breaks – why? Take breaks – why? Distributed vs. Massed Practice Effect Distributed vs. Massed Practice Effect Match Learning and Testing Conditions Match Learning and Testing Conditions ….or at least move around a lot ….or at least move around a lot

The End