basic research methodologies psych 231: research methods in psychology
Post on 21-Dec-2015
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An example
Claim: People perform best with 8 hours of sleep a night.
How might we go about trying to test this claim? – How should we test it (what methods)? – What are the things (variables) of interest? – What is the hypothesized relationship between these
variables?
General research approaches Descriptive: Describe variables as they exist
– Observational – Survey – Case studies
Correlational - measures two (or more) variables in order to describe the relationship between them
Experimental: Systematic manipulation and observation of non-naturally occurring events
Observational methods
The researcher observes and systematically records the behavior of individuals
– Naturalistic observation
– Participant observation
– Contrived observation
Naturalistic observation
Observation and description of behaviors within a natural setting– It is generally used with naturally occurring and
ongoing phenomena with little experimenter intervention
Naturalistic Observation
Can be difficult to do well– A lot of work is often needed to develop coding
systems of behavioral categories– Need to be careful not to influence the behaviors
as a result of being observed
Naturalistic Observation
Can be difficult to do well Good for behaviors that don’t occur (as well)
in more controlled settings– Walking example
Naturalistic Observation
Can be difficult to do well Good for behaviors that don’t occur (as well)
in more controlled settings Often a first step in the research project
– helps to identify what some of the important variables are
– then the next step is to move into more controlled settings for further tests
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
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
Advantages– may see patterns of behaviors that are very
complex and realized on in particular settings– often very useful when little is known about the
subject of study– may learn about something that never would have
thought of looking at in an experiment
Observational methods
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
Survey methods Widely used methodology
– those annoying things in the mail and by phone– US Census
Can collect a lot of data– Lots of participants in a short amount of time– Can collect subjective information
Done correctly, can be a very difficult method– constructing good questions, rating scales, etc.
Doesn’t provide clear cause-effect patterns
Case Histories
Intensive study of a single person, a very traditional method – Get a very detailed description– Fits well with clinical work
Typically an interesting (and often rare) case– The man who mistook his wife for a hat– NA (fencing accident, amnesia)
Case Histories
This view has a number of disadvantages– There may be poor generalizabilty– There are typically a number of possible
confounds and alternative explanations
Correlational Methods
Measure two (or more) variables for each individual to see if the variables are related
Used for:– Predictions– Reliability and Validity– Evaluating theories
Problems: Can’t make casual claims
Causal claims
We’d like to say: – variable X causes variable Y
To be able to do this:– The causal variable must come first– There must be co-variation between the two
variables– Need to eliminate plausible alternative
explanations
Causal claims Directionality Problem:
– Airplanes and coffee spills– Happy people sleep well
• or is it that sleeping well when you’re happy?
Third variable problem:– Do Storks bring babies?
• A study reported a strong positive correlation between number of babies and stork sightings
The experimental method 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
Advantages– Precise control possible– Precise measurement possible– Theory testing possible– Can make causal claims
The experimental method
Disadvantages– Artificial situations may restrict generalization to
“real world”– Complex behaviors may be difficult to measure