Interpreting and Generalizing your Results Psych 231: Research Methods in Psychology

Announcements This week in labs: POSTER SESSIONS Jen has final papers available at her office hours (not in class today) Amanda’s may be done by labs this week

Research Results Goal of Research –Experiments: To establish a cause and effect relationship between independent and dependent variables –Correlational studies To determine potential relationships between different variables

Interpretation of your results Statistical significance –Tell us if differences or (relationships with correlations) go beyond what we’d expect by chance –Don’t tell us anything about what the result really means in theoretical terms

Interpretation of your results Theoretical Significance –Return to your theory(ies) Reject them? Support (not prove) them? Revise them? –What are the limitations of your interpretations? Are there alternative theories still to test? –Yes, there are always going to be alternatives (not always good ones) Do your results generalize well?

Generalizing results External validity revisited –What limits/constraints were imposed because of: the use of experimental control availability of resources –Participant factors (who did you test?) Volunteers College students Sex Culture –Location/setting factors (where did you test?) College Region Laboratory

Generalizing results –Experimenter factors Personality, sex, experience as experiementer –Experimental items Do the results only apply to the stimuli that you used, or would they extend to others –E.g., memory for: »cat, dog, truck, car, … all concrete objects –Would the same pattern of results be seen for: »call, dig, truth, cut, … more abstract concepts » cath, dob, trush, caf, … all non words

Threats to external validity as interactions Generalization as interactions –Does your theory (or anyone else’s) predict an interaction? –If you collect the appropriate data/controls, you can do some statistical tests

In defense of college students Convenient? –Yes, but not because researchers are lazy –Researchers do have limited resources Criticisms about generalizability need to be backed up with theory and/or data College students are after all humans Replications with other samples provide a safegaurd against limited generalizability

Replications Importance of replications –Demonstrate that the results weren’t a “one time” thing Single failure to replicate - don’t panic Repeated failure to replicate - original results probably wrong (maybe a Type I error)

Replications Types of replications –Exact replications Replication of the research as precisely as possible –Conceptual replications Same independent variables, but measured in a different way –Same conceptual variables, different operational variables

Increasing External Validity Aggregation –Grouping together data Over participants Over stimuli or situations Over trials or occasions Over measures (converging operations)

Increasing External Validity Non-reactive measurements –Unobtrusive measures Observation without participant awareness –Naturalistic observation To validate experimental findings –Field experiments Experimentation outside of the lab

Example Results from Lab studies –Self awareness reduces likelihood of people engaging in socially undersirable behaviors (e.g., cheating or lying)

Beaman, Klentz, Diener, & Sanum (1979)

“Hi, what’s your name?” “Hi, what are you dressed as?”

Please take only one piece of candy

The big picture Generalizing your to the outside world –The bottom of the hourglass –How do these results impact … –Not always stated in the report –But, should always be in the back of your mind. why are you doing the research? why is it important? who will benefit from this research?

Next time Review of course