Using the scientific method Psych 231 Research Methods

Using the scientific method Psych 231: Research Methods in Psychology

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

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

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

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

n Naturalistic Observation: Observation and description of behaviors within a natural setting n Jane Goodall n n 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 Dian Fossey Observational Methods

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

n Survey methods: Questionnaires and interviews that ask people to provide information about themselves n Widely used methodology Best way to collect some kinds of information: • Descriptive, behavioral, and preferential n • e. g. , demographic information, recreational behavior, and attitudes n 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

n Archival data: Rather than making direct observations, researcher examines existing public or private records n n 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 n Data may be of observations that you cannot (ethically) collect or manipulate • E. g. , murder rates, who marries whom, etc. n Word of caution: be aware of how and where the data were collected Observational Methods

n Advantages n n n 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 n Disadvantages n n Causality is a problem Threats to internal validity because of lack of control • Every confound is a threat • Lots of alternative explanations n n Directionality of the relationship isn’t known Sometimes the results are not reproducible Observation without manipulation

n Systematic (Contrived Observation): The observer sets up the situation that is observed n n 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

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

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

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

We’d like to say: n variable X --causes--> variable Y To be able to do this: n § § 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

Theory 1: Storks deliver babies

Theory 2: Underlying third variable

n n Manipulating and controlling variables in laboratory experiments Must have a comparison n At least two groups (often more) that get compared One groups serves as a control for the other group Variables n n n 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

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