1 research strategies: how psychologists ask and answer questions module 3
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Research Strategies: How Psychologists Ask and Answer
QuestionsDescription The Case Study
The Survey
Naturalistic Observation
Correlation Correlation and Causation Illusory Correlation Perceiving Order in Random
Events
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Research Strategies: How Psychologists Ask and Answer
QuestionsExperimentation Exploring Cause and Effect
Evaluating Therapies
Independent and Dependent Variables
Statistical Reasoning Describing Data
Making Inferences
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Descriptive MethodsCase Study
A technique in which one person is studied in depth to reveal underlying behavioral principles.
Is language uniquely human?
Advantage: tremendous amount of detail.Disadvantage: cannot apply to others.
Famous case study: Phineas Gage
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Survey
A technique for ascertaining the self-reported attitudes, opinions or behaviors
of people usually by questioning a representative, random sample of people.
http://ww
w.lynnefeatherstone.org
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Survey
Wording can change the results of a survey.
Q: Should cigarette ads and pornography be allowed on television? (not allowed vs.
forbid)
Wording Effect
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Survey
A tendency to overestimate the extent to which others share our
beliefs and behaviors.
False Consensus Effect
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Survey
Random SamplingFrom a population, if each member has an
equal chance of inclusion into a
sample, we call that a random sample
(unbiased). The fastest way to know about the marble color ratio is to blindly transfer a few into a smaller jar and count them.
Population – all the cases in a group
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Descriptive Methods• Naturalistic observation – watching animals
or humans behave in their normal environment.
• Major Advantage:– Realistic picture of behavior.
• Disadvantages:– Observer effect - tendency of people or
animals to behave differently from normal when they know they are being observed.
• Participant observation - a naturalistic observation in which the observer becomes a participant in the group being observed (to reduce observer effect).
Naturalistic and laboratory settings
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Descriptive Methods• Laboratory observation – watching animals
or humans behave in a laboratory setting.• Advantages:
– Control over environment.– Allows use of specialized equipment.
• Disadvantage:– Artificial situation that may result in
artificial behavior.
• Descriptive methods lead to the formation of testable hypotheses.
Naturalistic and laboratory settings
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Correlation
When one trait or behavior accompanies another, we say the two correlate.
Correlation coefficient
Indicates directionof relationship
(positive or negative)
Indicates strengthof relationship(0.00 to 1.00)
r = 0.37+
Correlation Coefficient is a statistical measure of relationship
between two variables.
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Finding Relationships
• Correlation coefficient ranges from 0 to 1.00• Closer to 1.00, the stronger the relationship between
the variables.– No correlation = 0.0.– Perfect correlation = -1.00 OR +1.00.
• Positive correlation – variables are related in the same direction.– As one increases, the other increases; as one decreases, the
other decreases.• Negative correlation – variables are related in opposite
direction.– As one increases, the other decreases.
• CORRELATION DOES NOT PROVE CAUSATION!!!
Correlational technique
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Perfect positivecorrelation (+1.00)
Scatterplot is a graph comprised of points generated by values of two variables.
Scatterplots
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No relationship (0.00)Perfect negativecorrelation (-1.00)
Scatterplot on the left shows a negative correlation, and the one on the right shows no
relationship between the two variables.
Scatterplots
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Scatterplot
Scatterplot showing relationship between height and temperament in people with a moderate positive correlation of +0.63.
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Correlation Coefficient Interpretation
Coefficient
Range
Strength of
Relationship
0.00 - 0.20 Very Low
0.20 - 0.40 Low
0.40 - 0.60 Moderate
0.60 - 0.80 High Moderate
0.80 - 0.90 High
0.90 - 1.00 Very High
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Illusory Correlation
The perception of a relationship where none exists. Parents conceive children after adoption.
Confirming evidence
Disconfirming evidence
Do not
adopt
Disconfirming evidence
Confirming evidence
Adopt
Do not conceiveConceive
Michael N
ewm
an Jr./ Photo Edit
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Order in Random Events
Given large number of random outcomes, a few are likely to express order.
Angelo and Maria Gallina won two California lottery games on the same day.
Jerry Telfer/ S
an Francisco C
hronicle
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Experimentation
The backbone of research in psychology.
Experiments isolate causes and their effects.
Exploring Cause and Effect
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Many factors influence our behavior. Experiments (1) manipulate factors that interest us while keeping other factors
under (2) control.
Effects generated by manipulated factors isolate cause and effect relationships.
Exploring Cause & Effect
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The Experiment• Operational definition - definition of a
variable of interest that allows it to be directly measured.
• Independent variable (IV) - variable in an experiment that is manipulated by the experimenter.
• Dependent variable (DV) - variable in an experiment that represents the measurable response or behavior of the subjects in the experiment.
Experimental approach and terms
IV: Violent TV
Definition: Aggressive play
DV: Aggressive play
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For example, to study the effect of breast feeding on intelligence. Breast feeding is the independent variable.
For example, the effect of breast feeding on intelligence - intelligence is the dependent variable.
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In evaluating drug therapies it is important to keep the patients and
experimenter’s assistants blind to which patients got real treatment and which
placebo.
Evaluating Therapies
Double-blind Procedure
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Assigning participants to experimental (Breast-fed) and control (formula-fed)
conditions by random assignment minimizes pre-existing differences
between the two groups.
Evaluating Therapies
Random Assignment
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Random Assignment
SAMPLE
Control Group
Experimental Group
Test for Differences
LO 1.11 Experimental approach and terms
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Confounding Variables
SAMPLE
Control Group
Experimental Group
Are differences due to manipulation or confounding
variable (mood)?
LO 1.11 Experimental approach and terms
Menu
Effect of violent tv on aggression
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No Confounding Variables
SAMPLE
Control Group
Experimental Group
Differences due to manipulation, not an extraneous variable because
mood randomly determined.
LO 1.11 Experimental approach and terms
Menu
Effect of violent tv on aggression
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