experimental control Flashcards
experimental control
-ensuring only the iv changes across conditions
-avoiding alternative explanations:experimenter expenctacy effects,demand characteristics
optimizing our operational defenition
-avoiding ceeling and floor effects
-having an appropriate pairing of strong IV and sensitive DV
experimenter expanctacy effect
A cognitive bias that occurs when a researcher knows
what condition participants are in and therefore
intentionally or unintentionally manipulates an
experiment, thus impacting the findings.
thereat internal validity
ex:
maze bright/maze dull
1-participants were diveded intwo groups
2-one was told that their rats were super smart the other super stupid
3- they were told to see which one could do the maze faster
4- secretly the two animals were identical- not one was better then other
5- but the finding was that the ‘‘smart’’ rat was faster
6- the reason why probably was that the participants perhaps treated the rat better which inderactly caused the rat to act better
solution for experimenter expectacy effect
1-double blind study (reserch assistant and participants are blind to which one is getting the IV)
2-automated (computer ? )instructions
3-all conditions run simustaneous
demand characteristics
A demand characteristic is any feature of an
experiment that might inform participants of the
purpose of the study.
participants might try to help/hurt you
-be the good participants
-mess up the result
-socially desireability
sometimes a bit of deception is required
operational defenition of an IV manipulation
-straightfoward
-staged
straightfoward manipulation/simple and easy
Just present participants with something for the IV (e.g.
writing, pictures, video, etc) that will influence the DV
ex
-manipulate mood with music,a video, or a remenber a time when…..
(another)
-try to remeber as many words from the following list as u can
stage manipulation
1- try to inderetcly elicit a state
2- put particpansts in a position where they actually feel theyre in the situation
examples
1-elicit fustration by giving people an impossible task
1-elicit anger by having a confederate insut a participant
2- driving while on hands-free vs with a passenger
straight foward manipulation vs staged manipulation
Research question: Does thinking about old age impact
the behaviour of young people?
straight foward: ask participants to think about when they are 90 their expectations and afterwards walk around the room
staged manipulation: asked them to put words that relate to old age in order then ask them to walk around the room
deception
Often, we deceive subjects about the real purpose of
a study
₋ “Unrelated tasks” (filler tasks)
₋ Use of confederates or cover story
Attempt to avoid demand characteristics
ex:line studya,shock study
but a debrif us needed afterwards
straightfoward pros
(perception)
-simple
-cheap
-very common
-easy to pull of
cons
-sometimes quite
artificial…might not really
simulate the “real world”(low mundane
realism)
-demand characteristics
staged pros (deception)
-high experimental realism
-can often avoid demand
characteristics
cons
-Tricky to pull off
-participants suspision
- hard to replicate
-lots can go wrong
-may be costly
-ethical?
measuring variable
celling effect
*strenght of iV
can cause big changes in DV
-bigger contrast between Iv
weak IV
may cause changes in Dv
smaller contrast between IV
sensitivity of DV : tough
dificult to change
*sensitivity of DV : sensitive
easy to change
question wording
-simplicity
-double -barreld question (2 seperate question insted of one with two possible responses )
-loaded questions (not-biasest)
-negative wording: to complex (avoid not)
creating survey question
-pre testing
-feed back
-have others asnwer the question
-revise questions
additional
-response set
-social desirability
operational defenition of a measured variable(DV)
-self-report
-behavioral
-physiological
celing effect
the point at which an independent variable no longer has an effect on a dependent variable, when a kind of saturation has been reached
floor effect
participants are all at minimum performence on DV so cant see effect of IV
an IV can be
strong and cause big changes by having two different Ivs that are very different
or
where the difference between IV’s are pretty small and causes small changes in DV
sensitivity of DV
a DV can be resistent to change or change easily
weaker Iv are harder to detect then a strong IV
Question wording
considerations (what is better in a questioneer/self-report?)
-simplicity(avoid jargon,abreviation,complexity)
-double barrel questions (with the word and )
-loaded question(bias)
-negative wordings (not,dont,cant)
pre testing
Have others answer the questions
– Ask for feedback
– Revise questions that are unclear or
misunderstood
* OR use an existing & validated questionnaire
to know if the questions of the questioners are good
response sets
a tendacy to respond to all questions from a particular perspective or ina particular way rather then providing the real answers
answering (from 1 to 10)
10,10,10
social desirability
aswering questions how others would/what would be accepitable rather then the truth
open-ended questions
pros:can get more complex and detail answers, can identify common themes
cons:responses may be ambigious, participants may interpret questions in differnt ways, time consuming to code
