Thinking Critically with Psychological Science

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Thinking Critically with Psychological Science

• Critical Thinking Scientific Attitude
• thinking that does not blindly accept arguments
  and conclusions
• examines assumptions
• discerns hidden values
• evaluates evidence
• Skeptical but not cynical. Open but not gullible.

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Limits of Intuition and Common Sense

• Hindsight Bias
• tendency to believe, after learning an outcome,
  that one would have foreseen it
• the I-knew-it-all-along phenomenon
• Overconfidence
• we tend to think we know more than we do

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Research Strategies

• Theory
• an explanation using an integrated set of
  principles that organizes and predicts
  observations
• Hypothesis
• a testable prediction
• often implied by a theory

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The Scientific Method
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Research Strategies

• Operational Definition
• a statement of procedures (operations) used to
  define research variables
• Example-
• intelligence may be operationally defined as what
  an intelligence test measures

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Research Strategies

• Replication
• repeating the essence of a research study to see
  whether the basic finding generalizes to other
  subjects and circumstances
• usually with different subjects in different
  situations
• Validity/Reliability (these arent the same)
• The instruments used for the research must
  accurately measure or predicts what it purports.

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Research Strategies

• Case Study
• an observation technique in which one person is
  studied in depth in the hope of revealing
  universal principles

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Research Strategies

• Survey
• technique for ascertaining the self-reported
  attitudes or behaviors of people
• usually by questioning a representative, random
  sample of them
• False Consensus Effect
• tendency to overestimate the extent to which
  others share our beliefs and behaviors

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Research Strategies

• Population
• all the cases in a group, from which samples may
  be drawn for a study
• Random Sample
• a sample that fairly represents a population
  because each member has an equal chance of
  inclusion

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Research Strategies

• If marbles of two colors are mixed well in the
  large jar, the fastest way to know their ratio is
  to blindly transfer a few into a smaller one and
  count them

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Research Strategies

• Naturalistic Observation
• observing and recording behavior in naturally
  occurring situations without trying to manipulate
  and control the situation

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Research Strategies

• Correlation Coefficient
• a statistical measure of the extent to which two
  factors vary together and thus how well either
  factor predicts the other

Indicates direction of relationship (positive or
negative)
Correlation coefficient
r .37
Indicates strength of relationship (0.00 to 1.00)
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Research Strategies

• Scatterplot
• a graphed cluster of dots, each of which
  represents the values of two variables
• the slope of the points suggests the direction of
  the relationship
• the amount of scatter suggests the strength of
  the correlation
• little scatter indicates high correlation
• also called a scattergram or scatter diagram

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Research Strategies
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Research Strategies
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Research Strategies
55 60 65 70 75
80 85

• Scatterplot of Height and Temperament

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Research Strategies

• Three Possible Cause-Effect Relationships

could cause
(1) Low self-esteem
Depression
or
(2) Depression
Low self-esteem
could cause
or
Low self-esteem
(3) Distressing events or biological predispositio
n
could cause
and
Depression
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Illusory Correlation

• Illusory Correlation
• the perception of a relationship where none exists

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Random Sequences

• Your chances of being dealt either of these hands
  is precisely the same 1 in 2,598,960.

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Thats enough for one day!
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Research Strategies

• Experiment
• the investigator manipulates one or more factors
  (independent variables) to observe their effect
  on some behavior or mental process (the dependent
  variable) while controlling other relevant
  factors by random assignment of subjects
• by random assignment of participants the
  experiment controls other relevant factors

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Research Strategies

• Double-blind Procedure
• both the subject and the research staff are
  ignorant (blind) about whether the subject has
  received the treatment or a placebo
• commonly used in drug-evaluation studies
• Placebo
• an inert substance or condition that may be
  administered instead of a presumed active agent,
  such as a drug, to see if it triggers the effects
  believed to characterize the active agent

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Research Strategies

• Experimental Condition
• the condition of an experiment that exposes
  subjects to the treatment, that is, to one
  version of the independent variable
• Control Condition
• the condition of an experiment that contrasts
  with the experimental treatment
• serves as a comparison for evaluating the effect
  of the treatment

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Research Strategies

• Random Assignment
• assigning subjects to experimental and control
  conditions by chance
• minimizes pre-existing differences between those
  assigned to the different groups

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Research Strategies

• Independent Variable
• the experimental factor that is manipulated
• the variable whose effect is being studied
• Dependent Variable
• the experimental factor that may change in
  response to manipulations of the independent
  variable
• in psychology it is usually a behavior or mental
  process

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Research Strategies
Comparing Research Methods
Research Method Basic Purpose
How Conducted What is
Manipulated
Descriptive To observe and
Case studies, surveys, Nothing record
behavior and naturalistic
observations
Correlational To detect naturally
Computing statistical Nothing occuring
relationships association, sometimes to
assess how well among survey one variable
predicts responses
Experimental To explore cause Manipulating
one or Independent and effect more
factors and using variable(s) random
assignment to eliminate preexisting diff
erences among subjects
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Research Strategies

• Design of the subliminal tapes experiment

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Statistical Reasoning
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Statistical Reasoning
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Statistical Reasoning

• Mode
• the most frequently occurring score in a
  distribution
• Mean
• the arithmetic average of a distribution
• obtained by adding the scores and then dividing
  by the number of scores
• Median
• the middle score in a distribution
• half the scores are above it and half are below it

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Statistical Reasoning

• A Skewed Distribution

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Statistical Reasoning

• Range
• the difference between the highest and lowest
  scores in a distribution
• Standard Deviation
• a computed measure of how much scores vary around
  the mean
• Statistical Significance
• a statistical statement of how likely it is that
  an obtained result occurred by chance

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Does Behavior Depend on Ones Culture?

• Culture
• the enduring behaviors, ideas, attitudes, and
  traditions shared by a large group of people and
  transmitted from one generation to the next