Human Cognitive Processes: psyc 345

Ch. 7 Long-term memory:

Encoding and retrieval

Takashi Yamauchi© Takashi Yamauchi (Dept. of Psychology, Texas A&M University)

• (Q1) What is the best way to store information in long-term memory?

• (Q2) What are some techniques to help us get information out of LTM when we need it?

• (Q3) How is it possible that a lifetime of experiences and accumulated knowledge can be stored in neurons?

• (Q1) What is the best way to store information in long-term memory?

Encoding

• What encoding strategy enhances long term memory?

• http://www.youtube.com/watch?v=0J9J_yD4-1k&NR=1

Level-of-processing theory

• Memory depends on depth of processing

• Deep processing vs. shallow processing– Focusing on an item’s meaning and relating it

to something else.

• Shallow processing– Little attention to meaning, attention to

physical features to items. Rote memory

Craik & Tulving (1975)

• Experiments:

– Levels of processing and remembering

– Deep processing helps• (Processing semantic information helps)

• CogLab: level of processing

Experiment:

• Tasks:

– Subjects were shown words one by one on a screen.

– They carried out one of 3 different tasks.

• Task1: Capital letters?

• low semantic involvement– Ss judged whether the word presented on the

screen is printed with capital letters or not.

– TRAIN yes– Table no

• Task2: Rhyme?– In another trial, Ss were shown a word (e.g., TRAIIN)

and judged whether or not the word rhymed with a word (e.g., BRAIN).

• Train brain - yes• Crate weight yes• Table cable yes• Book –> note no

• Task 3: Fill in the blanks

– Ss judged whether or not the word shown first fitted a particular sentence.

– E.g., “friend” was shown, and a sentence • “He met a in the street” was shown. • The answer is “yes”.

Different levels of depth

• Task 1 < Task 2 < Task 3

Memory test (recognition):

• After Ss carried out these tasks, then a list of 80 words was given. – In the list, 40 words appeared during the first

phase.– 40 words were new words that did not appear

in the first phase.

• Ss indicated the words that they remember from the first phrase.

These tasks differ in the level of processing.

Craik & Tulving 1975

Answer

Question Yes No

Structural Is the word in capital letters? TABLE table

Phonemic Does the word rhyme with WEIGHT crate MARKET

Category Is the word a type of fish? SHARK heaven

Sentence Would the word fit the sentence:

"He met a in the street?" FRIEND cloud

Processing semantic information

• The three tasks differed in the degree to which semantic information was processed.

• Fill in blanks > Rhyme > Capital letter

  

• Level of processing: (2:22)

– http://www.youtube.com/watch?v=0J9J_yD4-1k&NR=1

Fig. 6-18, p. 206

Additional factors that aid encoding

• Creating connections– Visualizing study items. – Relating study items to yourself. – Generating study items by yourself

• Bower & Winzenz (1970)– Ss received a list of 15 pairs, (boat, tree)…

– One group were told to just repeat the words.

– Another group were told to form mental pictures

•Ss in the mental picture group were able to recall twice as many words as the Ss in the repeat group.

Self-referencing effect

• Ss received a word list. – Sad, positive, overwhelming, sly, shy, happy,

…– They answered yes-no questions

• happy– Printed in small case? (physical

characteristics)

• snappy– Rhymes with happy? (rhyming)

• upbeat– Means the same as happy? (meaning)

• happy– Describe you? (self-reference)

• (Q2) What are some techniques to help us get information out of LTM when we need it?

Retrieving information from LTM

• What are effective ways of encoding and retrieving?

• Using retrieval cues

• Retrieval cues are like “hints” that are useful for retrieving memories.

Cued recall

• Mantyla (1986)

• Ss received a list of 600 nouns – (e.g., banana, freedom, tree, …)

• During learning, Ss wrote down three words and associated the words with each noun.– E.g., banana yellow, bunches and edible.

Cued recall

• Ss were given a surprise memory test.

• Ss were presented with the three words they had created. – e.g., yellow, bunches and edible

• 90% of the 600 words were recalled correctly.

• Another group of participants:– Did not create their own cues– But they were given cues that were produced

by someone else• E.g., banana yellow, bunches and edible.

• 55% of the words were recalled.

Fig. 6-28, p. 217

• Creating your own retrieval cues during encoding REALLY helps

Encoding specificity

• How are encoding and retrieval related?

• Encoding specificity theory

– Memory retrieval is effective to the extent by which the context of encoding corresponds to the context of retrieval (Tulving & Thompson, 1973)

• Godden & Baddeley (1975)– One group of Ss studied a list of words

underwater. – Another group studied the words on land. – At test, each group was further divided into and

recalled the words either underwater or on land.

Caption: (a) Design for Godden and Baddeley’s (1975) “diving” experiment. (b) Results for each test condition are indicated by the bar directly under that condition. Asterisks indicate situations in which study and test conditions matched.

Grant et al. (1998)

Caption: (a) Design for Grant et al.’s (1998) “studying” experiment. (b) Results of the experiment. Asterisks indicate situations in which study and test conditions matched.

• Other methods to improve your memory (2:50)

• http://www.youtube.com/watch?v=BBjr4jKYEpw&feature=related

• Things that impede your memory (1:35)• http://www.youtube.com/watch?

v=OHl7BewJ0yU&feature=PlayList&p=8DE5E0C927437E3B&playnext=1&playnext_from=PL&index=32

• (Q3) How is it possible that a lifetime of experiences and accumulated knowledge can be stored in neurons?

How are memories stored in the brain

• Hebb (1948)• http://en.wikipedia.org/wiki/Donald_O._Hebb

• Learning and memory are represented by physiological changes at the synapse.

• Long-term potentiation (LTP)

Neuron IV

Neurons

Dendrites

Cell body

Axon

Synapse

Dendrite Axon

Synapse

Synapse and neurotransmitter

neurotransmitters reach a terminal of a dendrite of the other neuron, and change the neuron’s resting potential.

Fig. 6-20, p. 209

• Neuroanimator demonstration

– Ch 13. 3: Long-lasting LTP

Forming Memories in the brain: The fragility of new memories

• Memory loss• Teenage memory loss due to concussion

(2:11)– http://www.youtube.com/watch?

v=gv4SJN016hQ

• H. M. – his hippocampus is surgically removed.– He cannot form new memories– He also lost memories of events up to 10-15

years before the operation.

Fig. 6-21, p. 209

H. M. had both anterograde and retrograde amnesia

Consolidation

• These examples show that memory for recent events is more fragile.

• Some process of transferring of memory occurs.

Consolidation– Transforms new memories to a stronger less

fragile state.

Consolidation

Retrieval of episodic memory initially depends on the hippocampus.

Later, the hippocampus is not involved in retrieval.

How does it happen?

-- >reactivation

Fig. 6-22, p. 211

Incoming information activates cortical areas and the hippocampus

The hippocampus replays the neural activities associated with a memory. This results in the formation of connections between cortical areas.

Eventually, the cortical connections become strong enough, and the hippocampus is no longer necessary.

What creates consolidation?

• Sleeping helps strengthen memory.

• A lot of neural connections between hippocampus and neocortex.

• Neurons in hippocampus send neural signals to neurons in neocortex while you sleep.

• Synapse and learning (10:45)

• Teenagers and sleep deprivation– http://www.youtube.com/watch?

v=pqpOZd2LtIo&feature=PlayList&p=8DE5E0C927437E3B&index=24&playnext=2&playnext_from=PL

• Poor sleep and Alzheimer’s disease– http://www.youtube.com/watch?

v=WOC5a9h5_dk

Additional materials

Memory for emotion

• A strong connection between emotion and memory.

• We tend to remember well emotionally charged experiences (both negative and positive).

• Why?

Fig. 6-26, p. 214

LaBar & Phelps (1998)

Arousing words (profanity, sexually explicit words) are remembered better than neutral words

Dolcos et al. (2005)

Emotional pictures are also remembered better than neutral pictures.

Why

The amygdala is the center for processing emotion.

The hippocampus is right next to the amygdala.

• What happens if you don’t have amygdala?

• DVD: Secrets of the mind – (Capgras delusion; from 29:00 to 39:00 ) 10 min.

• A case study (imposter feeling) of a patient with the damage to amygdala.

• http://www.youtube.com/watch?v=dqBGzkz1oDU