Using the scientific method
Psych 231: Research
Methods in Psychology
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This week’s labs - Library Labs:
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Next week’s labs:
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Milner rooms 164d (for the psycINFO lecture)
North East classroom 3rd floor (to meet with the
GAs)
Check out Bruce’s library page (link on syllabus too)
Download and read the Assefi & Garry (2003) article
before labs
GA office hours & locations
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Jim: Tu 12-1 DeGarmo 12
Kevin: Tu 9-10 DeGarmo 12c
Lab Announcements
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Claim: People perform best with a good
night of sleep.
• To begin to answer it we’ve got to FOCUS the idea
• Break the general idea down into smaller more specific ideas
• Develop theories as to how & why
• EVALUATE the idea (e.g., the ROT test)
• TEST the idea: using research methods to test parts of the
theories (hypotheses)
Conducting Research: An example
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Claim: People perform best with a good
night of sleep.
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Focusing the idea
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What do we mean by performance?
• Academic performance?
• Physical performance?
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What do we mean by “good night sleep”?
• 8 hrs?, Uninterrupted?, 3 hours of REM?
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What is the underlying theory?
• e.g., consolidation of memories happen during REM sleep, so getting more REM
sleep should lead to better recall
Conducting Research: An example
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Claim: People perform best with a good
night of sleep.
Evaluating the idea (ROT)
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Can we replicate the research, do we get similar results?
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Answer may depend on how you choose to make your
observations (your research methods)
How do we observe performance? How do we observe good
sleep?
• Recall tests, recognition tests, “brain waves,” ,,,
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Are our predictions testable?
Conducting Research: An example
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Claim: People perform best with a good
night of sleep.
How might we go about trying to test this claim?
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What are the things (variables) of interest?
What is the hypothesized relationship between these
variables?
How should we test it?
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How do we observe the behavior?
What research design should we use?
Conducting Research: An example
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Observational approaches: How do we
observe the behaviors of interest?
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Naturalistic observation
Participant observation
Survey & interviews
Archival data
Systematic (contrived) observation
General research approaches
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Naturalistic Observation: Observation and description
of behaviors within a natural setting
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Jane Goodall
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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
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Hard not to influence things
Takes a long time
Need multiple observers to agree
Dian Fossey
Observational Methods
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Participant Observation: The researcher engages in
the same behaviors as those being observed
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May allow observation of behaviors not normally accessible
to outside observation
Internal perspective from direct participation
• But could lead to loss of objectivity
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Potential for contamination by observer
Observational Methods
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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
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Archival data: Rather than making direct observations,
researcher examines existing public or private records
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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
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Data may be of observations that you cannot (ethically)
collect or manipulate
• E.g., murder rates, who marries whom, etc.
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Word of caution: be aware of how and where the data
were collected
Observational Methods
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Advantages
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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
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Disadvantages
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Causality is a problem
Threats to internal validity
because of lack of control
• Every confound is a threat
• Lots of alternative
explanations
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Directionality of the
relationship isn’t known
Sometimes the results are not
reproducible
Observation without manipulation
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Systematic (Contrived Observation): The observer
sets up the situation that is observed
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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
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Case studies
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Correlational
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Looking for a co-occurrence relationship between two
(or more) variables
Quasi-experimental
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Intensive study of a small set of individuals and their
behaviors
Experimental designs with one or more non-random
variables
Experimental
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Investigating the cause-and-effect relationship between
two (or more) variables through the manipulation of
variables
Types of research designs
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Intensive study of a single person, a very
traditional method
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Typically an interesting (and often rare) case
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Phineas Gage
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Sept 13, 1848 Explosion
propelled a railroad tamping
rod through his brain
This view has a number of disadvantages
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There may be poor generalizabilty
There are typically a number of possible
confounds and alternative explanations
Descriptive: Case Histories
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Measure two (or more) variables for each
individual to see if the variables co-occur
(suggesting that they are related)
Used for:
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Predictions
Reliability and Validity
Evaluating theories
Problems: Can’t make casual claims
Correlational Methods
We’d like to say:
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variable X --causes--> variable Y
To be able to do this:
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There must be co-variation between the two variables
The causal variable must come first
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Directionality problem
• Happy people sleep well
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Or is it that sleeping well when you’re happy?
Need to eliminate plausible alternative explanations
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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
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Manipulating and controlling variables in laboratory
experiments
Must have a comparison
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At least two groups (often more) that get compared
One groups serves as a control for the other group
Variables
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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
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Advantages
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Precise control
possible
Precise measurement
possible
Theory testing possible
Can make causal
claims
Disadvantages
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Artificial situations
may restrict
generalization to
“real world”
Complex behaviors
may be difficult to
measure
The experimental method