Critical Thinking and Psychological Science

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Critical Thinking and Psychological Science
Critical thinking means
Examining assumptions
Discerning hidden values
Evaluating evidence
Keeping an open mind
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Critical Thinking and Psychological Science
Critical thinking vs Common Sense
Common sense, or intuition, is not always reliable
Hindsight bias
Overconfidence
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Scientific Research
What Science Is
a method for acquiring and organizing knowledge
What Science Is Not
the only method for acquiring and organizing
knowledge
a way to prove that things are true
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Scientific Research
Theory
an explanation using an integrated set of
principles that organizes and predicts
observations
Hypotheses
Testable predictions (generally implied by
theory)
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Scientific Research
The Scientific Method
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The Operational Definition
An operational definition is the result of a
decision to accept an objectively observable
event or events as representing the occurrence of
some internal, subjective event. Such
definitions are almost always open to argument.
e.g., happy jumping up and down
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Scientific Research
Three basic types of research design
Naturalistic Observation
Correlation (quasi-experimental)
Experimental Studies
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Naturalistic Observation
Case Study
Surveys / Questionnaires
Field Studies
behavior is natural
- little or no control
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Correlational Studies
Correlation The extent to which a relationship
exists between 2 variables
The relationship may be positive (as one variable
goes up so does the other), negative (as one goes
up the other goes down), or there may be a zero
correlation (no relationship)
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r .37
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Correlational Studies
The Scatterplot
Usually the most effective way to view
correlational data
HEIGHT
WEIGHT
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Correlational Studies
The slope of the line of best fit indicates the
direction of the relationship (positive or
negative)
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Correlational Studies
How tightly clustered the points are around the
line of best fit indicates the strength of the
correlation
moderate positive
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Correlational Studies
How tightly clustered the points are around the
line of best fit indicates the strength of the
correlation
Strong positive
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Correlational Studies
How tightly clustered the points are around the
line of best fit indicates the strength of the
correlation
Strong negative
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Correlational Studies
If there is no relationship, there will be no
pattern to the points on the graph, and the line
of best fit will be flat (no slope).
No correlation
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Correlational Studies
Correlation and Cause and Effect
If you discover a positive correlation between
height and IQ, does this mean
a) Being smart makes you taller
b) Being tall makes you smarter
c) Some third factor (e.g., good nutrition) makes
people both smarter and taller
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Correlational Studies
Correlation and Cause and Effect
A correlation tells you that a relationship
exists between 2 variables (aside from the 3rd
variable problem), but tell you absolutely
nothing about cause and effect.