Research Methods:

Psychology as a Science

How do you know… That George Washington was the first U.S.

President?

How do you know… That you have a stomach?

How do you know… That the sun will rise tomorrow?

How do you know… That there aren’t little creatures inside

computers that are responsible for the things computers do?

How do you know… That you don’t have a hole in the back of your

pants today?

How do we know what we know?

1) Authority (Dogmatism)

2) Reason (Rationalism)

3) Observation (Empiricism)

Science uses Reason AND Observation

Four Goals of Psychology Description Prediction Explanation Control

The Scientific Method

Hypothesis = educated guess about how two variables are

related Must be testable

Theories = general principles that attempt to explain

why two or more variables are related. broad, simple, generative

The Scientific Method

Ask a question

Form a Hypothesis

Test yourHypothesis

Find and ReportResults

Descriptive Research

1. Case Study

2. Survey

3. Observation natural settings laboratory settings

Correlational ResearchA correlationcorrelation is a relationship between variables

1. Positive correlation (var A ↑, var B ↑)

2. Negative correlation (var A ↑, var B ↓)

3. No correlation = no relationship

Three Reasons for any correlation: X causes Y, Y causes X, or Z causes X and Y

Remember...

CORRELATION DOES NOT INFER CAUSATION!

Observation #1

Observation: A physiological psychologist observes that people with higher levels of the neurotransmitter dopamine exhibit more behaviors associated with schizophrenia than those with lower levels of dopamine.

Type of Correlation?Explanations?

Observation #2

Observation: A college professor found that the more class absences students have, the lower their grade in the course tends to be.

Type of Correlation?

Explanations?

Observation #3Observation: A politician running against a

candidate who had been in office for eight years pointed out that violent crime had increased steadily during those eight years even though the administration had put more funding towards fighting crime.

Type of correlation?Explanations?

Observation #4Observation: An industrial/organizational

psychologist observes that people who are most satisfied with their jobs perform at higher levels than people who are dissatisfied.

Type of correlation?Explanations?

Experimental ResearchCan determine causation

Independent variable Dependent variable random assignment

control group placebo

Blinding Single-blind study

Double-blind study

Since experiments tell us cause and effect, why do correlational research?

Ethical Issues in Psychological Research Right to privacy Informed consent

use of deception right to withdraw

Animal rights Is there justification for discomfort or harm a

research procedure may produce?