Mythbusters Handouts
Used in:
Burkley, E., & Burkley, M. (in press). Mythbusters: A tool for teaching research methods in psychology. Teaching of Psychology.
I. DoesToastAlwaysLand Buttered-Side Down (episode #28)
1. Why did Jamie and Adam create elaborate toast-dropping machines?
To remove the influence of human error and to increase experimental control
2. Why does Adam first run a control study on his machine using only non-buttered toast?
To calibrate the measure. To make sure the outcome was random and not due to bias.
3. Why do the Mythbusters want their toast-dropping machine to be a “less naturalistic model”?
To remove the impact of extraneous influences (e.g., human error)
4. An observed score is made up of what two variance components? By using a “less naturalistic model,” the Mythbusters are reducing which of these components?
Observed score = True Score + Measurement Error
Using a less naturalistic model reduces measurement error
5. In their final study, the outcome is measured on what scale of measurement?
Nominal (Toast was recorded as either butter-up or butter-down)
6. Of the three types of measures discussed in class (observational, physiological, self-report), which one are the Mythbusters using in this study?
Observational measure
7. What was the conclusion of the study?
Myth Busted - Butter did not influence which side the toast landed on
II. Is Yawning Contagious? (episode #28)
1. What is the independent variable in this study?
Seed Yawn – whether Carrie yawns at the participants or not
2. What is the dependent variable in this study?
If the participant yawns or not
3. The Mythbusters don’t discuss this in the episode, but how would you operationally define a yawn?
Example definitions: Wide open mouth, inhaling and exhaling, Mouth open for specified time
4. Is their dependent variable measured in a disguised or non-disguised way?
Disguised measure of behavior (Hidden Camera)
5. What were the results of this study? Do you agree with their conclusion?
Myth confirmed:
25% yawned in control grp
29% in experimental grp
6. Would you consider the effect a large or small one?
Small effect. But small effects can be important in some circumstances.
7. At the end of the episode, Adam says “given our large sample, I think it is confirmed”. Why does the size of the sample matter?
When the sample size is large, it is less likely that the results are due to chance (Remember discussion on Interitem reliability – we are more confident when we make multiple observations and in this case, each participant is an observation)
III. Is Talking on a Cell Phone While Driving as Bad as Driving Drunk? (episode #33)
1. What is the Mythbusters exact research hypothesis?
Talking on the cell phone (not dialing, distratction, etc.) will impair driving at a level equivalent to drunk driving
2. What is the independent variable in this study?
Different driving conditions
3. Was the IV manipulated?
Yes
4. How many levels did the IV have?
Three: Control, Driving while on cell phone, Driving while drunk
5. What is the dependent variable in this study?
Performance on the driving exam (as rated by a driving instructor)
6. Was this IV within-subjects or between-groups?
Why did they choose to do it this way and not the other?
Within-subjects design
Because there is wide variability in driving skills (introduces error)
7. Do you see any problems with this study?
If so, how would you resolve them?
Possible order effects – could counterbalance
However, it was smart for them to choose the order they did, b/c prevented alcohol from carrying over into other conditions
Practice effects could have occurred, but this would have made participants perform better (not worse) on the later conditions (contradicts their hypothesis)
8. What were the results of this study?
Myth confirmed – Participants drove worse when on cell phone and when drinking compared to control
IV. Who Gets Wetter? Running vs. Walking in the Rain (episode #1)
1. What is the Mythbusters exact research hypothesis?
Running in the rain will make you wetter (Jamie) / dryer (Adam) than walking in the rain
2. How many independent variables are in this study? What are they?
2 IVs:
Running vs. walking in the rain
Presence of wind or not
3. How many levels are there to each IV? What are they?
2 levels to each IV
5. What is the dependent variable in this study?
The change in weight of the coveralls
6. What type of design is this?
Factorial design
7. How many conditions are there?
Four conditions
8. How many main effects are there? How many interactions are there?
2 Main effects (walking vs. running; wind vs. no wind)
1 Interaction (Speed x Wind)
9. What extraneous variables do they try to control? How do they try to control them?
a) Rain characteristics (velocity, drop size, spread of drops). Controlled by creating fake rain and dropping high enough so reaches terminal velocity
b) Perspiration. Controlled by using latex suits underneath coveralls
10. What were the results of this study? What main effects and or interaction(s) were significant?
Main effect of speed (Running led to greater weight increase than walking)
No main effect of wind
No interaction
11. Do you think this study was high in internal validity? Why?
Do you think it is high in external validity? Why?
Probably high in internal validity (control over extraneous variables)
Probably not high in external validity (fake rain and wind, concrete flooring, no puddles)
12. Why do you think the Mythbuster’s results were different than those from the Climate Control study conducted in NC?
The NC lab conducted the study outside during a real rain storm, so rain characteristics could have varied. Also used 1 person to walk in the rain and another to run, so individual differences may have influenced the data (i.e., confound).