Lecture 8: Forgetting, Context and Memory Flashcards
1
Q
What is trace decay theory?
A
- Each rehearsal strengthens memory trace
- Trace decays over time
2
Q
How did Jenkin’s and Dallenbach’s study provide evidence against the trace decay theory?
A
- Shows that NOT just decay
- One condition studied just before bed then woke up and given a memory test (recall of nonsense syllables) to see how much they had forgotten ( if you slept for 4 or 8 hours etc. the memory should’ve faded over time)
- The other group were awake and active after learning (had the same amount of time before the test as sleep condition)
- Graph with results: X- axis = retention interval (in hours), y axis = accuracy (in number of syllables)
- If you give people the test right after learning (short interval) people did the best. And as you extend the retention interval performance gets worse. According to trace decay theory memory recall should have been the same for both conditions because its just time that decays memory (decrement in performance should’ve been the same bc it doesn’t matter what you’re doing, it’s just time). Results showed that the performance went down more rapidly for people who were awake, the sleep/rest condition did better (i.e., more accurate) with longer intervals
3
Q
What is the interference theory?
A
- Memories don’t just ‘fade’ away
- Two types of interference: Proactive and retroactive. These are paradigms, i.e., different ways of looking at memory loss
4
Q
What is the typical task associated with the interference theory?
A
- Typical task: paired-associate learning
- Something from column A was paired with a specific item from the B column (e.g., MTZ- CAH). The task was to learn these pairs. Which could take quite a few trials. Then you are given a second list where things from the A column are paired with items from the C column. In the testing phase you are given the first item and have to recall the second or paired item.
- Notice that in list 2 column A is the same, so you are given the same items with a new pairing
5
Q
What is proactive interference?
A
- Learn 1 (A-B), Learn 2 (A-C), Test (A-C)
- Control group only learned the A - C pairings (learned list 2 only)
- The experimental group is going to experience proactive interference (learns list 1 first and list 2 second)
- The control group does better than the experimental group because they have no interference (i.e., two sets of pairings)
- Premise of proactive interference: something you’ve learned earlier/first interferes with something you learn later/second
6
Q
What is retroactive interference?
A
- Learn 1 (A-B), Learn 2 (A-C), test (A-B)
- Experimental group will experience retroactive interference. A-C interferes with A-B (C word intrudes into A-B list).
- control group just learned A-B
- Premise: what you learn later or second, interferes with something you learned earlier or first
7
Q
What are the general interference findings?
A
- In both PI and RI paradigms, recall is worse for experimental than Control groups.
Why? (we know that it’s not due to memory trace fading away because we can control for time and see otherwise)
(1) Response competition
(2) Unlearning
(3) List Differentiation
8
Q
What is response competition?
A
- Occurs when A is paired with two alternatives (competition between memories of the two lists)
- A-B (mtz - cah) then A- C (mtz-tms)
- Graph: RI paradigm. Y axis = amount of RI interference from baseline and x axis = number of trials (5, 10, 20 up to 40)
- The higher up the slope is on the graph means the worse you do on the first list (i.e., the more retroactive interference you experience. The more trials or practice you have on A-C list the worse you do on recalling the A-B list (the first list). After a while the association of the A column with C pairings is so strong that you have trouble recalling the B pairings, but why?
- According to Response competition theory this happens because when you are trying to generate the B items there is competition from the second list (A-C). It competes to the extent that participants will generate the C items rather than the B items. This is what happens initially. After about 5 trials, the second list is no longer competing /intruding (the # intrusions decrease as number of trials increase). It only explains the first part in this paradigm of interference. Something else is happening (the A-C line should continue going up with the other if response competition was the explanation).
9
Q
What is unlearning?
A
- Original associations (A-B) are unlearned
- Barnes & Underwood (1959)
– Modified free recall technique:
– learn A-B
– vary amount of study on A-C
– test session: give A, recall B and C - Conclude: As List 2 (A-C) associations are learned (stronger), List 1 (A-B)
becomes unlearned. It’s not about response competition because participants must report both.
10
Q
What are the problems with the unlearning theory?
A
- Postman & stark
- Task: RI paradigm and Recognition test (rather than recall)
- Sometimes items from the first list, sometimes from the second and sometimes not either
- Results: no evidence for RI
- Suggests:
- A-B associations are NOT unlearned
- A-B traces still exist, but become harder to access? Simply suppressed?
11
Q
What is list differentiation hypothesis?
A
- Interference occurs because of failure to discriminate which list has been learned (and which list needs to be retrieved from)
- Underwood & Freund (1968) (time is one way to differentiate these lists)
- PI: A-B varied interval
- Little PI at long delay!
- Long interval facilitates differentiation of list
- General idea: if cues makes list distinctive, then better able to retrieve
- Wickens (1972)
- release from PI
- Control group: learned lists of consonant strings and then tested on consonant string
- Experimental: learned strings of numbers and then tested on consonant strings
- Each condition’s performance decreases the more they had to learn. However, in the last phase/trial the experimental group shows a release from a proactive interference due to sorting out the lists, performance goes back up. If you change the category you can keep information separate
12
Q
What is encoding specificity (Tulving)?
A
General idea:
- 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.
13
Q
Can learning context influence memory/ test performance?
A
- Smith, Glenberg, & Bjork
- Learn off campus (nice modern setting lawyers office, with formally dressed researcher) vs. Learn on campus (researcher in tshirt, in a plain small office)
- When learned off campus and tested off campus = good memory, when learned off campus and tested on campus = poor memory.
- Shows: The environment in which you learn something can have an impact on how well you do. Environmental context can aid retrieval.
- Not just the items you are focusing on getting stored but also the environmental cues - Godden and Baddeley
- Had people in the navy learn a list of items underwater with cards, tested later either underwater (same) or on the surface. Then had people learning on the surface and tested on the surface or underwater
- when Learning context is the same as test context, people performed well (e.g., underwater and underwater)
14
Q
Can mood affect recall?
A
Bower (1991)
- State dependent learning: Hypnosis mood induction
- Results: recall same mood > recall different mood
- Shows: mood is a contextual cue
- Overall, happy group did better than the sad group on the test
15
Q
What is the typical study used to test the credibility of eyewitness reports?
A
- show film of event (car accident)
- series of questions to influence the re-encoding
- memory test
