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Chapter 2Psychology’s Scientific Method

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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

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Scientific Method

Science is a method.

It’s not what you study,

but how you study it.

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Scientific Method

1. observe some phenomenon

2. formulate hypothesis and predictions

3. test through empirical research

4. draw conclusions

5. evaluate the theory

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Scientific Method: Observe

Step 1

Observe some phenomenon

curiosity

variables

theory

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Scientific Method: Hypothesize

Step 2

Formulate hypotheses and predictions

testable prediction

derived from theory

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Scientific Method: Research

Step 3

Test through empirical research

operational definition of variables

analyze data using statistical procedures

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Scientific Method: Conclusions

Step 4

Draw conclusions

replication of results → reliability

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Scientific Method: Evaluate

Step 5

Evaluate the theory

change the theory?

peer review and publication

meta-analysis

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Descriptive Research

Goal: Describing a phenomenon

observation surveys and interviews case studies

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Descriptive Research

Descriptive research does

not answer questions about

how and why things are the

way they are.

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Correlational Research

Goal: Identify relationships

correlation coefficient: r

-1.00 ≤ r ≤ 1.00

strength of relationship: magnitude

direction of relationship: + / -

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Correlation Coefficients

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Scatter Plots

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Correlational Research

Positive Correlations factors vary in same direction ↑ and ↑ … or … ↓ and ↓

Negative Correlations factors vary in opposite direction ↑ and ↓ … or … ↑ and ↓

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Correlation and Causation

correlation does not equal causation

third variable problem

longitudinal design

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Experimental Research

Goal: Determine causation

random assignment

independent variable(s) – manipulation

dependent variable(s) – measurement

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Experimental Research

Experimental Group independent variable is manipulated

Control Group treated equally, except no

manipulation of independent variable

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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?

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Bias and Expectations

experimenter bias

demand characteristics

research participant bias

placebo effect

double-blind experiment

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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?

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Applying Different Research Methods to Same Phenomenon

Example: Election of President Barack Obama

Possible Research Methods

observation

survey and interview

case studies

correlational research

experimental research

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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

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Research Settings

“Artificial” world – laboratory setting controlled setting

Real world - natural setting naturalistic observation

What are the advantages and disadvantages

of each setting?

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Analyzing and Interpreting Data

Statistics mathematical methods used to report data

Descriptive Statistics describe and summarize data

Inferential Statistics draw conclusions about data

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Descriptive Statistics

Measures of Central Tendency mean median mode

Measures of Dispersion range standard deviation

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Inferential Statistics

does data confirm the hypothesis?

statistical significance

α = 0.05 (confidence level)

bridge between sample and population

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Research Ethics

research participants have rights Institutional Review Board (IRB) APA Guidelines

informed consent

confidentiality

debriefing

deception

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Animal Research in Psychology

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

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Reality TV – Ethical Issues

informed consent?

deception?

psychological and/or physical risk?

is the behavior real?

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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

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Expressive Writing & 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

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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.

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Chapter Summary

Steps of the Scientific Method observe, hypothesize, research,

conclude, evaluate

Research Methods and Settings descriptive, correlational, and

experimental studies conducted in natural settings or the lab

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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