introduction to psychology methods: experiments, surveys and correlations prof. jan lauwereyns...
TRANSCRIPT
Introduction to Psychology
Methods: Experiments,Surveys and correlations
Prof. Jan Lauwereyns
http://www.sls.kyushu-u.ac.jp/~dubito/links
Look under “Classes”
Check “Psychology”
• Research Question:Research Question: Will participants be more altruistic if they see a video depicting human suffering?
• Research Question:Research Question: Will participants be more altruistic if they see a video depicting human suffering?
• Method:
Research Participants
Video Amount Donated
IV: Video of starving children in Africa. DV: Amount of money donated by subjects to UNICEF.
$3.64$3.64
• Research Question:Research Question: Will participants be more altruistic if they see a video depicting human suffering?
• Method:
Research Participants
Video Amount Donated
IV: Video of starving children in Africa. DV: Amount of money donated by subjects to UNICEF.
$3.64$3.64
PROBLEM:PROBLEM: Is $3.64 high, low, or medium?
Would it help to add a pretest?
• Allows us to statistically compare pre and post scores• If donation goes from low to high than we may
conclude that our experiment worked• There are some potential problems with this design
Pretest
($ donated)
Video Post-test
($ donated)
Research Participants
One group pretest/post-test designOne group pretest/post-test design
$3.64$3.64$2.85$2.85
TestingTestingTestingTesting
Taking the pretest may change the participant’s responses on the post-test.
How to Avoid• Determine whether a pretest is necessary• Disguise your pretest
Some problems are hard to avoid,but can be taken into account:
Comparing an experimental condition against a control condition
But watch out for those confounding factors…
Research Participants
Video Amount Donated
Research Participants
Control Group (neutral video)
Amount Donated
PsychologyPsychology
MarketingMarketing $2.45$2.45
$4.82$4.82Experimental group:
Control group:
A new problem
SelectionSelectionSelectionSelection
Participants who form the two groups in the experiment are chosen from existing natural groups
How to Avoid• Randomly assign participants to conditions • If not possible, try to get equivalent groups
Anatomy of a Good Experiment: Effects of Video on AltruismRepresentative Sample
Random Assignment
Experimental Group Control Group
Persuasive video Neutral video
Behavior ($ donated) Behavior ($ donated)
Operational Definition of Altruism= $ donated to UNICEF
Experimental
Control
20 2010 10
1 1015 520 10
100 580 1520 2020 1010 5
29.60 11.0032.77 5.68
Standard deviation
Average
Not significant
Experimental
Control
Experimental
Control
20 20 20 2010 10 20 10
1 10 11 1015 5 25 520 10 20 10
100 5 60 580 15 80 1520 20 20 2020 10 20 1010 5 20 5
29.60 11.00 29.60 11.0032.77 5.68 22.07 5.68
-40
+10
Experimental
Control
Experimental
Control
20 20 20 2010 10 20 10
1 10 11 1015 5 25 520 10 20 10
100 5 60 580 15 80 1520 20 20 2020 10 20 1010 5 20 5
29.60 11.00 29.60 11.0032.77 5.68 22.07 5.68
-40
+10
Experimental
Control
Experimental
Control
20 20 20 2010 10 20 10
1 10 11 1015 5 25 520 10 20 10
100 5 60 580 15 80 1520 20 20 2020 10 20 1010 5 20 5
29.60 11.00 29.60 11.0032.77 5.68 22.07 5.68
-40
+10
Smaller standard deviation
Significant
Not significant
Size Weight
176 81163 57159 52189 84172 89191 81167 67182 78171 60163 66
173.3 71.511.08603 12.7301
Size Weight
176 81163 57159 52189 84172 89191 81167 67182 78171 60163 66
173.3 71.511.08603 12.7301
Positive correlation:
More of one thing,corresponds with more of
another thing
Positive correlation:
More of one thing,corresponds with more of
another thing
More speed, more accidents
Negative correlation:
More of one thing,corresponds with less of
another thing
Negative correlation:
More of one thing,corresponds with less of
another thing
More training, less accidents
No correlation:
More of one thing,does not correspond with more
or lessof another thing
e.g., Survey about driving behavior
Ask about…-age, experience-how often drive, what kind of car…-where, how fast…-past accidents, traffic violations…
Try to establish correlations
e.g., Survey about driving behavior
Ask about…-age, experience-how often drive, what kind of car…-where, how fast…-past accidents, traffic violations…
Try to establish correlations
[ Can be inspiration for new experiments ]
