good theories & basic methodologies psych 231: research methods in psychology
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Good Theories & Basic Methodologies
Psych 231: Research Methods in Psychology
Announcements
Quiz 3 due date error: I’ve reset the due date on Quiz3 to Wednesday (9/10) to make up for accidentally having it close yesterday instead of today
Exam 1: One week from Wednesday
Properties of a good theory
Organizes, Explains, & Accounts for the data If there are data relevant to your theory, that your
theory can’t account for, then your theory is wrong• Either adapt the theory to account for the new data • Develop a new theory that incorporates the new data
The chicken or the egg?
Exclusive usage of one or the other can be problematic Typically good research programs use both
Theory
Data
Induction Deduction
“Data driven research”reasoning from the data to the general theory
“Theory driven research”reasoning from a general theory to the data
Properties of a good theory
Organizes, Explains, & Accounts for the data Testable/Falsifiable – can’t prove a theory, can
only reject it
“No amount of experimentation can ever prove me right; a single experiment
can prove me wrong.”
Omnipotent Theory
Beware theories that are so powerful/general/flexible that they can account for everything. These are not testable. Karl Popper claimed that Freudian theory isn’t falsifiable
• If display behavior that clearly has sexual or aggressive motivation, then it is taken as proof of the presence of the Id
• If such behavior isn’t displayed, then you have a “reaction formation” against it. So the Id is there, you just can’t see evidence of it.
So, as stated, the theory is too powerful and can’t be tested and so it isn’t useful
EXTINCTION OF THE DINOSAURS FULLY EXPLAINED
Another nice article on this
Properties of a good theory
Organizes, Explains, & Accounts for the data Testable/Falsifiable Generalizable
The theory should be broad enough to be of use, the more data that it can account for the better
The line between generalizability and falsifiability is a fuzzy one.
Properties of a good theory
Organizes, Explains, & Accounts for the data Testable/Falsifiable Generalizable Parsimony (Occam’s razor)
For two or more theories that can account for the same data, the simplest theory is the favored one
“Everything should be made as simple
as possible, but not any simpler.”
Properties of a good theory
Organizes, Explains, & Accounts for the data Testable/Falsifiable Generalizable Parsimony Makes predictions, generates new knowledge
Predictions about things that the theory wasn’t explicitly designed to account for
Conducting Research: An example
Claim: People perform best with 8 hours of sleep a night.
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 (what methods)? Today’s focus
General research approaches
Descriptive Describing the current state of the individual variables
• Observational, Survey, Case studies
Correlational Investigating the relationship between two (or more)
variables
Experimental Investigating the cause-and-effect relationship between
two (or more) variables
Descriptive: Observational methods
Observational methods The researcher observes and systematically records
the behavior of individuals
• Naturalistic observation
• Participant observation
• Contrived observation
Descriptive: Observational methods
Naturalistic Observation: Observation and description of behaviors within a natural setting
Jane Goodall
Dian Fossey
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
Descriptive: Observational methods
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
Descriptive: Observational methods
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
Descriptive: Observational methods
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
Descriptive: Survey methods
Widely used methodology More detail in Week 11
Can collect a lot of data Done correctly, can be a very difficult
method Doesn’t provide clear cause-effect patterns
Descriptive: 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
Intensive study of a single person, a very traditional method Typically an interesting (and often rare) case
Phineas Gage Sept 13, 1848 Explosion
propelled a railroad tamping rod through his brain
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: 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
Theory 1: Storks deliver babies
Theory 2: Underlying third variable
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
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
Disadvantages Artificial situations
may restrict generalization to “real world”
Complex behaviors may be difficult to measure