Make your own free website on

The Science of Psychology
Experimental Psychology
Lecture, Chapter 1

Ways to Acquire Knowledge
Tenacity – persistence in maintaining or adhering that certain knowledge is true

Authority – credibility of the person presenting the information

Experience – knowledge based on personal interactions with others and environment

Reason & Logic – forming a deduction (logical syllogism) based on an incorrect assumption

Science –
    Objective measurements
    Ability to verify others’ measurements
    Self-correction of errors and faulty reasoning
    Controlling for extraneous variables

Components of the Scientific Method

Confirmation of findings



The Psychological Experiment
Experiment – an attempt to determine the cause-and-effect relations that exist in nature

IV – independent variable
Independent = stands alone
Variable = state will “vary” between a minimum of 2 levels

DV – dependent variable
Variable that is measured, under which data is collected.
Changes in this variable are subject to the IV.

Extraneous variables – external, unwanted variables that can influence the DV

Ex. Industrial psychologist measuring relationship between productivity and plant lighting.

Establishing Cause-and-Effect Relations
Freeman and Punzo (2001):

IV manipulated (DNA evidence vs. eyewitness testimony

DV measured (jurors’ verdict)

Extraneous variables

The Research Process
Finding a problem
Reviewing the literature
Theoretical considerations
Research design
Conducting the experiment
Data analysis
Decisions in terms of past research and theory – interpretation of results and conclusions
Preparing the research report
Sharing your results
Finding a New Problem