Research Methods
AP Psych – Chapter 2
Psychology’s Scientific Method
Alice F. Short
Hilliard Davidson High School
Psychology Majors
• 2 Most Commonly Required Classes:
– Research
– Statistics
A SHORT Time to Ponder
Why would these be the two most required
classes for psychology majors across the
country?
Chapter Preview
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Psychology’s Scientific Method
Types of Psychological Research
Research Samples and Settings
Analyzing and Interpreting Data
Conducting Ethical Research
Thinking Critically About Research
Scientific Method and Health and Wellness
A SHORT Time to Ponder
• As a society, do we value critical thinking?
• Is critical thinking uncomfortable sometimes?
Scientific Method
• Science is a method.
• (It’s a VERB)
• It’s not what you study, but how you study it.
– any objective person can use the scientific method
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observe some phenomenon
formulate hypothesis and predictions
test through empirical research
draw conclusions
evaluate the theory
Scientific Method – 1. Observe
• Step 1: Observe some phenomenon
– curiosity
– variables
– theory
Scientific Method – 2. Hypothesize
• Step 2: Formulate hypotheses and predictions
– testable prediction
– derived from theory
Scientific Method – 3. Research
• Step 3: Test through empirical research
– operational definition of variables
– analyze data using statistical procedures
Scientific Method – 4. Conclusions
• Step 4: Draw conclusions
– replication of results → reliability
– If other people cannot replicate your study, then
your result are unreliable.
– What could this potentially mean for your study?
(Think critically!)
Scientific Method – 5. Evaluate
• Step 5: Evaluate the theory
– change the theory?
– peer review and publication
• publish or perish
– meta-analysis – method by which researchers
combine results across studies to establish the
strength of an effect
– theory = broad umbrella category which can either be
supported or refuted by testable hypotheses
Descriptive Research
• Goal: Describing a phenomenon
– observation
– surveys and interviews
– case studies
• Descriptive research does not answer
questions about how and why things are the
way they are
Correlational Research
• Goal: Identify relationships (does not mean
there is a causal relationships)
– correlation coefficient: r
• -1.00 ≤ r ≤ 1.00
– strength of relationship: magnitude
– direction of relationship: + / -
Correlational
Coefficients
Scatter
Plots
Correlational Research
• Positive Correlations
– factors vary in same direction
– ↑ and ↑ … or … ↓ and ↓
• Negative Correlations
– factors vary in opposite direction
– ↑ and ↓ … or … ↑ and ↓
Correlation and Causation
• correlation does not equal causation
• third variable problem
– Why would some people not WANT to consider a
third variable problem?
• longitudinal design
Experimental Research
• Goal: Determine causation
– random assignment – extremely important in
experimental design
– independent variable(s) – manipulation
– dependent variable(s) – measurement
• All of these vocabulary terms are very
important to KNOW!
Experimental Research
• Experimental Group
– independent variable is manipulated
• Control Group
– treated equally, except no manipulation of
independent variable
Validity
• External Validity
– representative of real world issues?
– do results generalize to the real world?
• Internal Validity
– are dependent variable changes the result of
independent variable manipulation?
– bias? logical errors?
Bias and Expectations
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experimenter bias
demand characteristics
research participant bias
placebo effect
double-blind experiment
Example of Experimental Research:
Self Esteem
• Baumeister’s research findings:
– “high self esteem leads to aggression”
• Donnellan & Trzesniewski’s research findings:
– “low self esteem leads to aggression”
• What accounts for these different findings?
– lab-only aggression?
– type of self esteem?
Applying Different Research Methods
to the Same Phenomenon
• Example: Election of President Barack Obama
• Possible Research Methods:
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observation
survey and interview
case studies
correlational research
experimental research
Research Sample
• Population
– entire group about whom conclusion drawn
• Sample
– portion of population actually observed
• Representative Sample
– characteristics similar to population
– opposite of “biased sample”
• Random Sample
– equal chance of being selected
Research Settings
• “Artificial” world – laboratory setting
– controlled setting
• Real world - natural setting
– naturalistic observation
• DISCUSSION: What are the advantages and
disadvantages of each setting?
Analyzing and
Interpreting
Data
• Statistics
– mathematical methods used to
report data
• Descriptive Statistics
– describe and summarize data
– Measures of Central Tendency
• mean
• median
• mode
– Measures of Dispersion
• range
• standard deviation
• Inferential Statistics
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draw conclusions about data
does data confirm the hypothesis?
statistical significance
α = 0.05 (confidence level)
bridge between sample and
population
A SHORT Time to Ponder
• What is the difference between descriptive
statistics and inferential statistics?
Research Ethics
• research participants have rights
• Institutional Review Board (IRB)
• APA Guidelines
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informed consent
confidentiality
debriefing
deception
Animal Research in Psychology
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animal research has benefited humans
used by 5% of researchers
rats and mice used 90% of time
standards of care in animal research
– housing
– feeding
– psychological and physical well being
Reality TV – Ethical Issues?
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informed consent?
Deception?
psychological and/or physical risk?
is the behavior real?
• DISCUSSION: What do YOU think?
A Wise Consumer…
is skeptical yet open-minded!
• Cautions
– exercise caution in applying group trends to
individual experience
– avoid overgeneralizing results
– look for converging evidence
– question causal inferences
– consider the source
Expressive Writing and Health
• Results of study on suicide v. accidental death
– different survivor health
– different survivor rate of talking about the loss
• Results lead to study on writing
– those assigned to write about a trauma
experienced better physical health
Chapter Summary
• Explain what makes psychology a science.
• Discuss common research settings and the 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 the effect of writing
about ones trauma.
Chapter Summary
• Steps of the Scientific Method
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4.
5.
observe
hypothesize
research
conclude
evaluate
• Research Methods and Settings
– descriptive, correlational, and experimental
studies conducted in natural settings or the lab
Chapter Summary
• Data Analysis and Interpretation
– descriptive and inferential statistics
• Challenges: Research Ethics and Bias
– APA guidelines and the IRB
• Expressive Writing and Health and Wellness
– benefits of writing about trauma