Chapter 2
Psychology’s Scientific Method
© 2008 The McGraw-Hill Companies, Inc.
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Psychology and the Scientific Method
Research Settings and Methods
Data Analysis and Interpretation
Challenges: Research Ethics and Bias
Application: Health and Wellness
© 2008 The McGraw-Hill Companies, Inc.
What Makes
Psychology a Science?
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Scientific Approach
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Curiosity
Skepticism
Objectiveness
Thinking critically
Collaboration
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Peer-reviewed research
Meta-analyses
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The Scientific Attitude
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Curiosity
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Skepticism
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Objectivity
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Thinking Critically
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Collaboration
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Peer Review
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Publication
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Research/Scholarly Journals
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Meta-Analysis
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The Scientific Theory
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What is a Theory?
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What is a Scientific Theory?
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Broad idea or set of closely related ideas
Attempts to explain observations
Makes predictions about future events
Connects observations and research
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Scientific Method: Observation
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Operational Definitions
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Objective description of variables
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How will variables be measured?
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Scientific Method: Hypothesis
Formulate Hypothesis
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Testable prediction
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Derived from theory
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Scientific Method: Research
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Collect Data
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Select participants
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Population – entire group of interest
Sample – subset of population
Random sampling
Design Study / Select Research Method
Analyze Data
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Data – all information collected in a study
Use statistical procedures to understand data
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Scientific Method: Conclusions
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What do the results mean?
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Statistical data analysis
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Replication of results (reliability)
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Revise theory?
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Research: Terms & Settings
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What?
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Variable – anything that varies
Where?
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“Artificial” world – laboratory setting
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Advantages and disadvantages?
Real world - natural setting
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Advantages and disadvantages?
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Descriptive Research
Goal: Observe and Record Behavior
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Naturalistic observation
Surveys and interviews
Standardized tests
Case studies
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Correlational Research
Goal: Identify Relationships
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Correlation coefficient: r
-1.00 ≤ r ≤ 1.00
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Strength of relationship: #
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Direction of relationship: + / © 2008 The McGraw-Hill Companies, Inc.
Correlation Coefficients
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Scatter Plots
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Correlational Research
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Positive Correlations
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Factors vary in same direction
↑ and ↑ … or … ↓ and ↓
Negative Correlations
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Factors vary in opposite direction
↑ and ↓ … or … ↑ and ↓
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Correlation and Causation
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Correlation does not equal causation
Third Variable Problem
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Multivariate approach
Longitudinal design
Advantages and Disadvantages of
Correlational Research
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Experimental Research
Goal: Determine Causation
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Random Sampling and Assignment
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Independent Variable(s) – Manipulation
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Dependent Variable(s) – Measurement
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Experimental Research
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Experimental Group
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Receives IV manipulation
Control Group
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Treated equally, but no IV manipulation
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Psychology’s
Research Methods
Insert figure 2.4 here
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Validity
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Ecological validity
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Representative of real world issues?
Do results generalize to the real world?
Internal validity
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Are DV changes the result of IV manipulation?
Bias? Logical errors?
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Bias and Expectations
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Experimenter Bias
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Research Participant Bias
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Placebo Effect
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Double-Blind Experiment
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Intersection: TMT Theory
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Ernest Becker – human life and culture
Terror Management Theory (TMT)
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Death “awareness” leads to worldview defense
Empirical Support
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Rosenblatt and others (1989)
Landau and colleagues (2004)
Routledge and others (2004)
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Analyzing and Interpreting Data
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Statistics
Mathematical methods used to report data
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Descriptive Statistics
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Describe and summarize data
Inferential Statistics
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Draw conclusions about data
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Descriptive Statistics
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Measures of Central Tendency
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Mean
Median
Mode
Measures of Dispersion
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Range
Standard deviation
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Inferential Statistics
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Does data confirm the hypothesis?
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Statistical significance
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α = 0.05 (confidence level)
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Significance vs. meaningfulness
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Research Ethics
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Research participants have rights!
Institutional Review Board (IRB)
APA Guidelines
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Informed consent
Confidentiality
Debriefing
Deception
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Animal Research in Psychology
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Animal Research and Human Problems
Prevalence of Animal Research
Animals Rights and Welfare
Institutional Animal Care and Use
Committees (IACUC)
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Minimizing Bias in Research
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Gender Bias
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Cultural and Ethnic Bias
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Research historically focused on males
Research historically focused on middlesocioeconomic-status European Americans
Overgeneralizations about ethnic groups
Currently research emphasizes diversity:
gender, ethnicity, socioeconomic status
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A Wise Consumer…
… is skeptical yet open-minded!
Cautions
 Distinguish between group results and
individual needs
 Avoid overgeneralizing results
 Look for converging evidence
 Question causal inferences
 Consider the source
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Application: Happiness
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The Science of Happiness
Subjective Well-Being
Happiness ↔ Life Success
Challenges to Becoming Happier
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The hedonic treadmill
The pursuit of happiness
© 2008 The McGraw-Hill Companies, Inc.
Chapter Summary
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Explain what makes psychology a science.
Discuss common research settings and the three
main types of research that are used in
psychology.
Distinguish between descriptive statistics and
inferential statistics.
Discuss some challenges that involve ethics, bias,
and information.
Discuss scientific studies on human happiness and
the nature of their findings.
© 2008 The McGraw-Hill Companies, Inc.
Chapter Summary
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The scientific method is marked by
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Curiosity, skepticism, objectiveness, and
critical thinking
Research settings and methods
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Descriptive, correlational, and experimental
studies conducted in natural settings or the lab
© 2008 The McGraw-Hill Companies, Inc.
Chapter Summary
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Data analysis and interpretation
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Challenges: Research Ethics and Bias
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Descriptive and inferential statistics
APA guidelines and the IRB
Application: Health and Wellness
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The scientific study of happiness
© 2008 The McGraw-Hill Companies, Inc.