Using the scientific method

1. Using the scientific method Psych 231: Research Methods in Psychology

2. Library Labs: • Milner rooms 164d (for the psycINFO lecture) • North East classroom 3rd floor (to meet with the GAs) • Next week’s labs: • Download and read the Assefi & Garry (2003) article before labs Lab Announcements

3. Going to hold off and talk about this in the next lecture when discussing APA style Reading a research article

4. Claim:People perform best with a good night of sleep. • How might we go about trying to test this claim? • What are the things (variables) of interest? • What is the hypothesized relationship between these variables? • How should we test it? • How do we observe the behavior? • What research design should we use? Conducting Research: An example

5. Observational approaches: How do we observe the behaviors of interest? • Naturalistic observation • Participant observation • Survey & interviews • Archival data • Systematic (contrived) observation General research approaches

6. Naturalistic Observation: Observation and description of behaviors within a natural setting • Good for behaviors that don’t occur (as well) in more controlled settings • Often a first step in the research project • Can be difficult to do well Jane Goodall Dian Fossey Observational Methods

7. Participant Observation: The researcher engages in the same behaviors as those being observed • May allow observation of behaviors not normally accessible to outside observation • Internal perspective from direct participation • But could lead to loss of objectivity • Potential for contamination by observer Observational Methods

8. Survey methods: Questionnaires and interviews that ask people to provide information about themselves • Widely used methodology • Best way to collect some kinds of information: • Descriptive, behavioral, and preferential • e.g., demographic information, recreational behavior, and attitudes • Large amounts of data can be collected quickly with relatively little cost (effort, time, etc.) • But they’re often not as “cheap” as you may think • Done correctly, can be a very difficult method Observational Methods

9. Archival data: Rather than making direct observations, researcher examines existing public or private records • If the appropriate existing records can be found, no need for data collection • Data set may be more extensive than what you could collect yourself • However, you are limited to the data that exists, may be no way to collect follow-up data • Data may be of observations that you cannot (ethically) collect or manipulate • E.g., murder rates, who marries whom, etc. • Word of caution: be aware of how and where the data were collected Observational Methods

10. Advantages • Complex patterns of behavior in particular settings • Useful when little is known about the subject of study • May learn about something that never would have thought of looking at experimentally • Disadvantages • Causality is a problem • Threats to internal validity because of lack of control • Every confound is a threat • Lots of alternative explanations • Directionality of the relationship isn’t known • Sometimes the results are not reproducible Observation without manipulation

11. Systematic (Contrived Observation): The observer sets up the situation that is observed • Observations of one or more specific variables made in a precisely defined setting • Much less global than naturalistic observations • Often takes less time • However, since it isn’t a natural setting, the behavior may be changed Observational Methods

12. Case studies • Intensive study of a small set of individuals and their behaviors • Correlational • Looking for a co-occurrence relationship between two (or more) variables • Quasi-experimental • Experimental designs with one or more non-random variables • Experimental • Investigating the cause-and-effect relationship between two (or more) variables through the manipulation of variables General research approaches

13. Phineas Gage • Sept 13, 1848 Explosion propelled a railroad tamping rod through his brain • This view has a number of disadvantages • There may be poor generalizabilty • There are typically a number of possible confounds and alternative explanations • Intensive study of a single person, a very traditional method • Typically an interesting (and often rare) case Descriptive: Case Histories

14. Measure two (or more) variables for each individual to see if the variables co-occur (suggesting that they are related) • Used for: • Predictions • Reliability and Validity • Evaluating theories • Problems: Can’t make casual claims Correlational Methods

15. We’d like to say: variable X --causes--> variable Y • To be able to do this: • There must be co-variation between the two variables • The causal variable must come first • Directionality problem • Happy people sleep well • Or is it that sleeping well when you’re happy? • Need to eliminate plausible alternative explanations • Third variable problem • Do Storks bring babies? • A study reported a strong positive correlation between number of babies and stork sightings Causal claims

16. Theory 1: Storks deliver babies

17. Theory 2: Underlying third variable

18. Manipulating and controlling variables in laboratory experiments • Must have a comparison • At least two groups (often more) that get compared • One groups serves as a control for the other group • Variables • Independent variable - the variable that is manipulated • Dependent variable - the variable that is measured • Control variables - held constant for all participants in the experiment The experimental method

19. Advantages • Precise control possible • Precise measurement possible • Theory testing possible • Can make causal claims • Disadvantages • Artificial situations may restrict generalization to “real world” • Complex behaviors may be difficult to measure The experimental method