P2 Lecture 8: Forgetting and Memory Context

Question 1

What is trace decay theory?

Answer 1

• • When we rehearse things, it strengthens the memory trace
• • Memory trace fades away over time, unless you rehearse or come back to it

Question 2

What was the Jenkins & Dallenbach study on memory decay?

Answer 2

• • two groups of people, one were awake and the others asleep
• • if memory loss is simply due to decay of information, then it shouldn’t matter if you’re awake or asleep
• • it turns out that the awake group had a lower accuracy in remembering nonsense syllables compared to the sleep group (shows that something else is interfering with out memory trace, and that interference is happening more when you’re awake than when you’re asleep)

Question 3

What is interference theory?

Answer 3

– memories don’t just “fade” away
– two types of interference:
Proactive: when something that you’ve learned now interferes with something that you will be learning later
Retroactive: when something that you’ve learned now interferes with something you’ve previously learned

Question 4

What is the paired-association task on interference theory?

Answer 4

– the person has to learn the pair of items in list 1 so that when they are given half of the pair (ex. mtz) they will know what the other pair is (ex. cah)
– in list 2, the A items are the same, but they have been paired with something else (C items)
– participants have to learn these pairs, and then during the test phase they have to generate either the B or C items associated with the A items
PROACTIVE
– Exp group learns list 1 (A-B) and list 2 (A-C), and then get tested on list 2 (A-C)
– control group only learns list 2 and gets tested on list 2
– in exp group, B (from list 1) interferes with C (from list 2); B word intrudes into C list
RETROACTIVE
– Exp group learn list 1 (A-B) and list 2 (A-C), but get tested on list 1 (A-B)
– control group only learns list 1 and tested on list 1
– in exp group, C (from list 2) interferes with B (from list 1); C word intrudes into B list

Question 5

Why is recall worse in experimental than control groups in interference studies?

Answer 5

• • In both PI and RI paradigms, recall is worse for Experimental than Control groups because…
    1) Response competition
• • occurs when A is paired with two alternatives
• • Competition between (B) and (C) ao you get intrusion errors
    2) Unlearning
• • Original associations (A-B) are unlearned
    3) List Differentiation
• • Interference occurs because of failure to discriminate which list has been learned.

Question 6

What was the Melton & Irwin study on response competition/unlearning?

Answer 6

• • Y axis is amount of retroactive interference and X axis is # trials on 2nd list
• • the more trials on learning the 2nd list, the more RI on first list
• • for the first 5 trials on learning the 2n list, the number of intrusions from 2nd list is the reason the RI on the first list increases (the participants pair the A item with the C item from second list instead of the B item from first list)
• • however, after 5 trials, the number of intrusions from 2nd list decreases (participants no longer pair the A item with C item from second list), yet they still get more RI (the second list items are not intruding anymore)
• • what’s happening is the first list is being unlearned (A-B connections are not just being interfered with they’re being unlearned)

Question 7

What was the Barnes & Underwood study on unlearning?

Answer 7

– Modified free recall technique:
learn A-B
vary amount of study on A-C
test session: give A, recall B and C
– as participants get more and more trials on the 2nd list, they get worse and worse on the first list, but they get better and better on the 2nd list
– this is because the first list gets unlearned and the connection gets stronger with the second list with more trials

Question 8

What is the problem with the unlearning theory (Postman & Stark study)?

Answer 8

• • RI paradigm
• • recognition test: the participants were given the actual items from first or second list (B or C) and they had to determine whether they were items that were previously paired with A
• • it turns out it shows no evidence for RI, the original A-B pairs from first list are not completely unlearned, they’re just not easy to access (the connections are still there, but suppressed)
• • lead to the list differentiation hypothesis

Question 9

What was the Underwood & Freund study on list differentiation?

Answer 9

• • had people learn the first list (A-B), then some varied interval later (short/long), they trained people on the second list (A-C)
• • they would then later on test the participants on the second list
• • when you do this, you get very little PI with the long delays (the long interval allowed these two lists to keep separated and helps with differentiation)
• • the cue (time in this case) makes the list distinctive and thus better able to retrieve

Question 10

What was the Wickens study on the release from PI?

Answer 10

• • the control group is proactive interference (learn one list of syllables, then a second, then a third, and then a fourth list, which is the test list)
• • the experimental group had to learn list of numbers rather than letters/syllables, but the last list they learned and were tested on were letters

Control; letters->letters->letters->letters
Experimental; numbers->numbers->numbers->letters

• • the control group shows PI, and so does the experimental group until they get to the final list (fourth trial) in which the experimental group does not experience PI
• • the experimental group was released from PI because they were able to differentiate the first three lists from the fourth list (going from numbers to letters whereas the control group goes from letters to letters and no way to differentiate)

Question 11

What is the Encoding Specificity?

Answer 11

• • Information is NOT encoded into memory as isolated individual items, but encoded as part of a richer memory representation that includes the context.
• • Context provides cues that are encoded & stored, and which can therefore influence retrieval
• • Memory is best when the retrieval cues match the encoded cues.

Question 12

What is the Smith, Glenberg, & Bjork study on the encoding specificity (campus)?

Answer 12

• • one group of students learned in a lab on campus where the researcher was wearing a lab coat, and the other group learned off campus in the lawyers building where the researcher was just wearing a suit
• • four groups in total; the ones that were learning on campus tested on campus and off campus, and the ones who learned off campus tested off campus and on campus
• • the groups that learned and tested in the same context did well on the various memory tests but the groups that learned in different contexts did poorly on the various memory tests

Question 13

What is the Godden & Baddeley encoding speciality study (surface/underwater)?

Answer 13

• • the navy divers had to learn a list of items either on the surface or underwater and then a test phase on the surface or underwater (four groups total)
• • the ones who learned in the same context as when they were tested did better (learn underwater and test underwater or learn on surface and test on surface

Question 14

What was the Bower study on encoding specificity (affective/mood)?

Answer 14

• • state-dependent learning: hypnosis mood induction
• • four groups: learn happy and test happy, learn happy and test sad, learn sad and test sad, learn sad and test happy
• • recall same mood > recall differ mood
• • shows mood is a contextual cue

Question 15

What is a typical/general study on eyewitness reports?

Answer 15

• • show people a series of slides, or a video of an incident (ex. Staged car accident) and then ask the participants a series of questions
• • the questions were designed in a way to see whether the persons memory for what they saw could be changed or altered

Question 16

What was the Loftus, Miller, & Burns study on eyewitness reports (stop/yield)?

Answer 16

– Series of slides of car turning at an intersection followed by an accident.
– after watching these series of slides, they were put in different groups
– there were four different groups; the group that saw the stop sign and were asked about whether they saw the stop sign, the group that saw the stop sign and was asked about whether they saw a yield sign, the group that saw a yield sign and were asked if they saw a yield sign, and the group that saw a yield sign and asked if they saw a stop sign (intervening/recoding phase)
– “Did the red car stop at the stop sign?” versus
“Did the red car yield at the yield sign?”
– Recognition test - choose between pairs of slides
– Critical slides: red car at “Stop “ vs. “Yield” sign
– 75% of the people chose the slide that was consistent with the question that was asked, even though they actually saw the other slide (even though they saw the car at the stop sign, if they were asked if the car stopped at the yield sign, they would pick the yield even though that’s not what they actually saw and vice versa)
– retroactive interference

Question 17

What was the Loftus & Palmer study on eyewitness reports (speed of car)?

Answer 17

– – a video of a car crash this time and participants were asked a series of questions on it
– all of the other questions were the same except the speed question
– depending on what verb used when asking how fast the cars were going, the participants had different answers on the speed
“smashed
collided
bumped
hit
contacted”
– people estimated that the cars were going on average 10 miles slower when the word “contacted” was used than when the word “smashed” was used
– –if the old encoding was overwritten –old memory was changed by the speed question- then the participants should “know” things consistent with this new encoding (asked how fast cars were going when smashed, to which they give a higher speed, and then asked if they saw any broken glass, and the ones who were asked about the speed with the word smash were more likely to say there was glass)
– retroactive interference