L33 Psych 301 Lecture Notes - Lecture 16: Interference Theory, Rhetorical Question, Sample Size Determination
7 Dec 2020
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• Pilot study:….
o 20 Lithuanian word pairs, given for 5 seconds a piece, one at a time, type the
English word
o Next phase while practicing pairs: half pairs showed up as restudied pairs, the
other half given as retrieval practice pairs
▪ Feedback after each trial→ correcting what you got wrong
• Feedback even given on restudied pairs for consistency
▪ 2x for each pair
o Retention interval of 1 hour
o Final test phase: 20 pairs tested (5 seconds)
▪ 10 were restudied previously, 10 were tested previously
• Some change that would make testing effect bigger, smaller, reversed, go away
o Some word-pairs that made some sense→ burna—mouth
▪ Split up word-pairs into “associated” word-pairs and non-associated
word-pairs
o No feedback→ shouldn’t change restudy condition, so will make retention
converge or reverse
• New manipulation: half of participants got no interference (unrelated activity—trivia),
half of participants had interference (learned more word-pairs)
o Interference=when info that is similar in format gets in the way of information
someone is trying to recall
▪ Proactive interference=earlier leaning impairs new learning
▪ Retroactive interference=new learning impairs earlier learning
• This new study is looking at RI
• Testing and interference—things we know
o Interference impacts testing/leaerning
o Testing protects against proactive interference
▪ Szpunar, McDermott, and Roediger (2008)
o What about retroactive interference?
▪ Evidence from existing literature is not quite as clear
▪ One paper that says testing does not protect against RI—Hupbach, 2015
▪ One paper that says testing does protect against RI—Potts & Shanks,
2012
• Variables and such→ Method section, design subsection
o IVA=practice type, within subjects
▪ Restudy
▪ Retrieval
o IVB=post-practice activity, between subjects
▪ Interference=new learning
▪ No interference=unrelated activity (trivia)
o DV=final cued recall
No interference
Interference
Retrieval
RT/NI
R/I
Restudy
RS/NI
RS/I
• Phase 1=learn list 1→ phase 2=post-practice activity (interference=learn list 2 vs. no
interference=trivia)→ phase 3=final cued recall test on list 1
o Phase 2
▪ Interference condition=learn list 2
• 20 new L-E pairs
• 5 seconds each
• Type (copy) English word
• 3x through the list→ need this to cause interference with the old
learning, so need the list to be learned sufficiently well
• Total time = 5 minutes
▪ No interference=unrelated activity=trivia
• also 5 minutes
• why (easy) trivia questions?
• Testing effect Method
o Why easy trivia questions? Because restudying is easy, not going to get anything
wrong while restudying
▪ Easy because don’t want participants to be over engaged
▪ If non-interference task was super difficult, participants confidence could
be affected, could be fatigued
• Also if hard trivia then may give up and start thinking about other
things, like the L-E word pairs they learned
▪ Learning new things could contribute to interference
• Even if learning unrelated material, could create some
interference
▪ Were they given feedback on trivia questions?
▪ Always getting it right in the interference condition, so should always get
right in no interference condition
o Slightly familiar with Lithuanian: slightly familiar=I know only a few Lithuanian
words
▪ Decided ahead of time that would include not familiar and slightly
familiar, but would check the people’s data who said slightly familiar to
make sure that they were in fact slightly familiar
▪ From “Lithuanian Familiarity” from APA Practice Paper Stuff
o Citations in method: don’t need to read those papers,
▪ Weinstein & Roediger,
• Part of logic of factorial experiments is: “given we know this main effect will happen
(anchor condition), what will happen when we do this?”
o Testing effect: tests enhance learning
▪ Retrieval>Restudy: the no-interference condition is most like typical
previous studies, so think of this as a baseline for the testing effect
o Retroactive interference: no interference>interference
▪ The restudy condition is most like typical previous studies, so think of this
as a baseline for the retroactive interference effect
▪ In the restudy condition, no interference should score higher than the
interference condition
o Now, competing predictions regarding an interaction:
▪ Retrieval practice eliminates or reduces RI: adding new L-E word pairs
should not cause performance to drop at all (strong condition) or should
cause performance to drop just a little bit (weak condition)
• Interference will reduce recall of restudied pairs, but not of pairs
given retrieval practice
o We know it will have an effect for restudy pairs, but we
don’t know the effect for retrieval pairs
• There will be a greater drop for restudy pairs than for retrieval
pairs
• In other words, the testing effect becomes larger in the
interference condition compared to the no interference condition
▪ Or, maybe retrieval practice does not eliminate or reduce retroactive
interference
• Then there will be the same drop from retrieval, no interference
condition to retrieval, interference condition as there will be from
restudy, no interference condition to restudy, interference
condition
• Both retrieval practice and restudy items will be impaired by
interference
• The size of the testing effect will not depend on interference
• APA formatting and style guide
o Personal pronouns where appropriate→ in practice paper, pretend you or we
did the research
o Active rather than passive voice
o Clear, concise, and plain
o In-text citations: necessary whenever you include information that is not of your
own creation→ ideas, claims, statistics, and more
▪ If not your own though, then cite
▪ Even if you think it’s your original thought, you might still need a citation
▪ Source should include the authors’ last name(s) and the year of
publication
• In parenthesis after a summary or paraphrase
• Or include the author’s name in the signal phrase, followed by the
year of publication in parenthesis
o Don’t separate author from year, keep close together
