Outline • Aquafina challenge • Internal and external validity • Basic dilemma • Practice Exercises • Ethics • Informed consent • Deception
The AquafinaChallenge • Do people like Aquafina or PSU H2O? • IV: Independent variable (cause/what is manipulated, effect of interest) • Aquafina vs. PSU H2O • DV: Dependent variable (outcome) • Liking (choice) • Confidence
Results • Number who selected it • D = 24/39 S = 15/39, which are equal Chi Square = 2.08, p = .15 P value = probability level – how likely it is that the results occurred by chance (p = .15 means 15% chance that results occurred by chance, want less than 5%, so not significant) • Confidence ( 0 to 10) 0 = not at all, 10 =very: • Range 0 to 10 • D = 5.58, S = 5.33 Greater than zero: t (38) = 13.48, p < .001 What can we conclude? D S
Conclusions • Not significant trend to like D better than S. • Whatever the person picked, they are confident in their choice. • Guess what – both were aquafina
Aquafina Challenge • What was manipulated? • Do you like first or second drink? • Do you like the letter D or S? • Do you like Left or Right drink?
Study Lacked: Internal Validity • Making sure nothing else but IV is different b/w conditions • Aquafina study had the following possible IV • Order (first or second) • Letter (D or S) • Side (left or right) • Solve by randomly assigning people to get different orders, letters, sides • Can one conclude anything? • People are pretty confident in their choice, even when they should not be.
External Validity External validity: do the results generalize across situations and people • Situations • Would people prefer D or S in lab? On street? In restaurant? • Is the situation realistic? • Mundane realism: does experimental set-up mirror real life? • Psychological realism: do the psychological processes triggered by the experiment mirror those found in real life? (more important than mundane realism) • People • Only applicable to college students, psych 221 students, people under 27?
The basic dilemma • Tradeoff between internal and external validity • Desire control over situation (Internal validity) vs. making sure results can generalize to everyday life (external validity)
Exercises H: People will report robbery more when alone than when in a crowd • What is the IV? Cause, thing manipulated • Alone or crowd • What is the DV? Outcome • Report or not • Is this an observational, experimental, or correlational study? • (Quasi) Experimental for could not randomly assign people to crowd or alone. • What are problems? • Random assignment • Crowd – friends or strangers? • Crowd – more socialable than alone
Staring and speeding H: Staring at people makes them uncomfortable, and then they try to escape Method: Cars stop at red light. Record time to cross intersection of 1st 250 cars, then stare at the next 250 and record time Results: Drivers who were stared at were faster.
What is the IV? • Staring vs. not • What is the DV? • Speed escaped • Is this an observational, experimental, or correlational study? • Experimental – manipulated staring • What are problems? • Random assignment • Measurement issues – starers might start timer later
Ethics (Black, White, Gray) • Simpson clip was here
Ethics • Ethics are not as clear cut as Simpson’s example • General principles • Promote accuracy, honesty, and truthfulness in science, teaching, and practice of psychology • Avoid harm – respect dignity and rights of people • Respect confidentiality • Debrief participants about the study • Obtain informed consent
Aspects of Informed Consent • Describe purpose/ procedures as much as possible • Told free to withdraw at any time (consequences of doing so) • Info from individual participants must be held in confidence, unless gain person’s permission • Release of tape for educational purposes • Risks/discomforts • Deception: only if no other means, IRB must approve, must debrief Obtain IRB approval (Institutional Review Board) – ORP (Office for Research Protections -what called at PSU) – need outside opinion
Reasons for Deception Ex: robbery study Deceived patrons, for unaware in study • Internal validity: • Use confederate to gain methodological control in robbery study • External validity: Do results generalize to real world? • If had knowledge, change results • Robbery – may be more likely to report it • Practical reasons • It would take forever to wait for a robbery • Ethical reasons • Can deceive to avoid harm • Fake robbery, then decrease chance of violence • tell participant that s/he will get shocked, when it won’t happen
Problems with Deception • Suspiciousness • Participants may think all studies involve deception • Act differently for fear of deception • Leak to others • Societal effects • Change perception of world • Limits informed consent • Deception is unethical if it interferes with participants’ understanding of important facts about the study that may influence their decision to participate.