Chapter 7: Human Memory Retention and Retrieval Flashcards
explain Penfield study about stimulating areas of the brain and how it relates to the idea that forgotten memories might still be in the brain
-Electrical stimulation of the cortex
-Stimulation of the temporal lobes with neurosurgical procedure
-Led to reports of memories that patients were unable to report in normal recall
-When people’s cortices were stimulated they were able to record memories that they were otherwise unable to recall
-No way to know if they remembered things they had forgotten, or if they are just making up things; did not know enough about peoples histories to know
what is experimental evidence (number word association study) that forgotten memories might still exist
NELSON (1971)
-Taught people number-word associations
-Create stimuli that people are going to know the same amount about, we all know the same about numbers and words
-Banana = 12; chair =3 for example
Tested them on these later
-People remembered some and forgot other ones
-Then, retaught them associations that they forgot
-Some people got taught the same associations as before and other people were taught new associations
-When tested, they recalled 78% of unchanged associations, but 43% of changed associations
Even though people had forgotten the original associations, there must have been something that has left behind since they remembered more of them
explain the study with the hammer that highlights potential memory for forgotten memories
People were asked to imagine how an artist would draw or functional uses for an object
-Ex. Hammer
-People told to either imagine ways to use it or how an artist would depict it
Were scanning brain activity while this was going on
-Brain activity pattern analyzer could distinguish between the tasks
-By looking at brain activity, program could tell if someone was picturing the hammer or a utilitarian use for it because it was different in the brain
-Later, when participants were shown words again, it could still distinguish, even for those they could not remember
-Could determine what people were told even if behaviorally a person could not remember what they were told / what they saw before
what are the two theories of forgetting
decay theory and interference theory
what is decay theory
Memory traces simply decay in strength with time
what is interference theory
Memory traces are replaced with interfering material
what are the two kinds of interference with inferencing theory
Retroactive interference: new piece of learning replaces your old information stored
Proactive interference: something you learned in the past gets in the way of your ability to retrieve something in the future
-Ex. Memory of old password is getting in the way of you learning your new one
what does the retention function of memory say
Memory performance systematically deteriorates with delay.
explain the two components of the retention function of memory
1) NEGATIVE ACCELERATION
-Rate of change gets smaller and smaller as the delay increases.
2) POWER LAW OF FORGETTING
-Memory performance deteriorates as a power function of practice.
study that highlights the retention function
Results from Wickelgren’s Experiment to Discover a Memory Retention Function
-Anytime you learn something and test yourself over a period of days on it, when there are times where you are not studying it or looking it over, initially there is a very steep drop off for how much you remember and overtime it eventually drops off
study of retention function with different languages
-Long-term retention of vocabulary words (up to fifty years)
BAHRICK (1984)
-Looking up retention of vocabulary words for languages that people learned
-Graphed a negative acceleration in a retention function
-Flat between 3 and 25 years
-Rapid between 25 and 49 years (due to cognitive decay)
retention function study with rats
RAYMOND AND REDMAN (2006): The retention function
-Showed decay functions may be found in associated neural processes
-Decreased LTP in rats hippocampus with delay
-If you continually stimulate a neuron (with an electrode or by practicing), the more likely it is to fire in the future, but the rate it increases goes down overtime
-Study in rats, when neurons are not stimulated, instead of becoming more likely to fire again, they become less likely to fire again, but this lesser rate of firing decreases over time
explain the interference study with related vs. unrelated words
How Interference Affects Memory
-Had both groups memorize the same list of words, one group memorized a list of similar words, the other group memorized one with different words
-The word that memorized the related list had a harder time recalling the first list than the group who learned something totally unrelated
what is the fan effect
increase in reaction time is related to an increase in the fan of facts emanating from the network representation of the concept.
study about the fan effect
Anderson (1974)
Study: taught people simple sentences / word associations (ex. The doctor is in the bank, the fireman is in the park)
-The first sentence just involves a doctor, the second two sentences just involve a lawyer, the last two sentences involve a park
-The doctor is in the bank
-The fireman is in the park
-The lawyer is in the church
-The lawyer is in the park
Lawyer and church is a 2-1 association because lawyer is associated with two things and church is associated with one
Later on, they showed people these sentences and other sentences they had not seen, interested in how quickly they identified the sentences, seeing how they quickly they could note the things they had seen before
Results: quicker to respond to sentences that has less associations, fits well with spreading activation theory; what is happening here is that the 1:1 ratio activation is not as spread out as the 2:2 ratio
-Memory structure gets half the activation because it is spread out elsewhere
explain the fMRI study with fan effect
(Sohn & colleagues, 2003)
-Response of the prefrontal cortex during verification of facts
-Contrasted high-fan sentences to low-fan sentences
-There is greater response in the high-fan condition.
-The greater activation means that your brain is having a harder time doing the task
what are redundancy effects and how do they impact interference
Major restriction on the situations in which interference effects are seen
-Redundancy among learning materials eliminates interference effects
-When facts are redundant or related to one another, learning more of them actually facilitates memory and makes it easier to remember things
study about redundancy effects and interference
Bradshaw and Anderson (1982)
Study: taught people facts in different conditions (teaching people a single fact, taught people three irrelevant facts, taught people three facts that had an obvious relationship to each other)
-Instant recall: people were good in all conditions
-Week later recall: people were best able to recall the related facts, followed by the single fact, then following by the irrelevant facts (with a huge drop off)