The Scientific Method in Psychology

A. There are 3 types of studies:

 

-1. Descriptive Studies (naturalistic observations, case studies).

Example: Individuals observed in their environment.

 

-2. Correlational studies

Establishing correlations between non-manipulated variables. Relationships are not necessarily causal.

 

-3. Experiments.

Manipulating variables and testing cause and effect relationships.

 

 

B. Theory Construction and a Philosophy of Science.

Theory: System of interelated ideas used to explain a set of observations

 

Hypothesis: specific prediction derived from theory

 

Designing experiments to test hypotheses and theory

 

The best way to advance knowledge is to attempt disproving a theory or hypothesis.

Alternative: design single experiment to test several contradictory hypotheses.

 

 

C. The Scientific Method.

 

-1. Identify a problem and formulate hypothesis

 

-2. Design experiment using dependent and independent variables

 

-3. Perform experiment using experimental and control groups

 

-4. Evaluate hypothesis (maybe reformulate corrected hypothesis and replicate data)

 

-5. Communicate results

 

 

D. Identifying a Problem

 

-1. Having a good idea

 

-2. The hypothesis

 

-3. The theory (one theory, several testable hypotheses)

 

-4. The Dogma

 

-5. Using naturalistic observations

 

 

E. Designing an Experiment

 

-1. Definitions

 

 

Dependent vs independent variable

 

 

Experimental vs control group

 

 

Validity (do the variables really reflect what they are supposed to manipulate or measure?)

 

-2. Independent variables (beware of confounding variables), and counterbalancing

 

 

F. Performing an Experiment

 

-1. Reliability of measurements (are the measurements repeatable?)

 

-2. Selecting the subjects (random assignment)

 

-3. Circumvent subject’s and experimenter’s expectations (placebo, double-blind studies)

 

 

G. Correlational Studies.

 

Correlations do not necessarily indicate a cause and effect relationship

 

 

H. Case Studies.

 

Not necessarily representative of entire population

 

 

I. Surveys.

 

Sample has to be representative of population

 

 

J. Generality

 

Generalize from a sample.