© 2011 The McGraw-Hill Companies, Inc. with snazzy editions by Mrs. Short

Chapter 2Psychology’s Scientific Method

© 2011 The McGraw-Hill Companies, Inc.

Fun Fact:

What are the two most commonly required classes for psychology majors across the country?

ANSWER: research statistics

© 2011 The McGraw-Hill Companies, Inc.

Chapter Preview

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

© 2011 The McGraw-Hill Companies, Inc.

A SHORT Time to Ponder

As a society, do we value critical thinking?

Is critical thinking uncomfortable sometimes?

© 2011 The McGraw-Hill Companies, Inc.

Scientific Method

Science is a method.

(It’s a VERB)

It’s not what you study,

but how you study it.

© 2011 The McGraw-Hill Companies, Inc.

Scientific Method

1. observe some phenomenon

2. formulate hypothesis and predictions

3. test through empirical research

4. draw conclusions

5. evaluate the theory

© 2011 The McGraw-Hill Companies, Inc.

Scientific Method: Observe

Step 1

Observe some phenomenon

curiosity variables theory

© 2011 The McGraw-Hill Companies, Inc.

Scientific Method: Hypothesize

Step 2

Formulate hypotheses and predictions testable prediction derived from theory

© 2011 The McGraw-Hill Companies, Inc.

Scientific Method: Research

Step 3

Test through empirical research operational definition of variables analyze data using statistical procedures

© 2011 The McGraw-Hill Companies, Inc.

Scientific Method: 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!)

© 2011 The McGraw-Hill Companies, Inc.

Scientific Method: Evaluate

Step 5

Evaluate the theory change the theory? peer review and publication meta-analysis

© 2011 The McGraw-Hill Companies, Inc.

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.

© 2011 The McGraw-Hill Companies, Inc.

Correlational Research

Goal: Identify relationships (not causal relationships) correlation coefficient: r

-1.00 ≤ r ≤ 1.00 strength of relationship: magnitude direction of relationship: + / -

© 2011 The McGraw-Hill Companies, Inc.

Correlation Coefficients

Scatter Plots

© 2011 The McGraw-Hill Companies, Inc.

Correlational Research

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

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

© 2011 The McGraw-Hill Companies, Inc.

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

© 2011 The McGraw-Hill Companies, Inc.

Experimental Research

© 2011 The McGraw-Hill Companies, Inc.

Experimental Research

Experimental Group independent variable is manipulated

Control Group treated equally, except no

manipulation of independent variable

© 2011 The McGraw-Hill Companies, Inc.

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?

© 2011 The McGraw-Hill Companies, Inc.

Bias and Expectations

experimenter bias demand characteristics research participant bias placebo effect double-blind experiment

© 2011 The McGraw-Hill Companies, Inc.

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?

© 2011 The McGraw-Hill Companies, Inc.

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

© 2011 The McGraw-Hill Companies, Inc.

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

© 2011 The McGraw-Hill Companies, Inc.

Research Settings

“Artificial” world – laboratory setting controlled setting

Real world - natural setting naturalistic observation

DISCUSSION: What are the advantages and disadvantages of each setting?

© 2011 The McGraw-Hill Companies, Inc.

Analyzing and Interpreting Data

Statistics mathematical methods used to report data

Descriptive Statistics describe and summarize data

Inferential Statistics draw conclusions about data

© 2011 The McGraw-Hill Companies, Inc.

Descriptive Statistics

Measures of Central Tendency mean median mode

Measures of Dispersion range standard deviation

© 2011 The McGraw-Hill Companies, Inc.

Inferential Statistics

does data confirm the hypothesis? statistical significance α = 0.05 (confidence level) bridge between sample and population

© 2011 The McGraw-Hill Companies, Inc.

A SHORT Time to Ponder

What is the difference between descriptive statistics and inferential statistics?

© 2011 The McGraw-Hill Companies, Inc.

Research Ethics

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

informed consent

confidentiality

debriefing

deception

© 2011 The McGraw-Hill Companies, Inc.

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

© 2011 The McGraw-Hill Companies, Inc.

Reality TV – Ethical Issues

informed consent? Deception? psychological and/or physical risk? is the behavior real?

DISCUSSION: What do YOU think?

© 2011 The McGraw-Hill Companies, Inc.

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

© 2011 The McGraw-Hill Companies, Inc.

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

© 2011 The McGraw-Hill Companies, Inc.

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.

© 2011 The McGraw-Hill Companies, Inc.

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

© 2011 The McGraw-Hill Companies, Inc.

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