Chapter 1: What is Psychology

The Experiment: Hunting for Causes

Introduction
Experimental Variables
Experimental and Control Conditions
Experimenter Effects
Conclusion



Introduction

The experimental method allows researchers to track down the likely causes of behavior.

Overiew of Steps in an Experiment

Glossary

Key Concepts Explained

Activities

Links

wwwlink: The American Psychological Association's Ethics Guidelines.


Experimental Variables

Introduction

This is the heart of the experimental manipulation to determine cause.

Glossary

Key Concepts Explained

One variable (independent variable) is manipulated by the researcher to see what its effect will be on the other variable (dependent variable).

Rules of thumb to decide which is the independent variable and which is the dependent variable;

If I drink caffeine (IV) when studying, then I will remember more for the test (DV).

Versus

If I remember more for the test (IV), then I will drink more caffeine (DV). This second statement just doesn't make good sense. Hence the first "if, then" sentence has correctly identified the independent and dependent variables.

Activities

NEED AND EXERCISE RIGHT HERE

Links

wwwlink: Tutorials written by students on conducting research.
wwwlink: Everything you ever wanted to know about designing research.

Experimental and Control Condition

Introduction

To establish cause and effect clearly, this step has to be included to eliminate any differences that might exist between groups of subjects and insure that everything is held constant except the manipulation of the independent variable.

Glossary

The Control Condition is a comparison condition in which the subjects are not exposed to the same treatment as in the experimental condition.

Key Concepts Explained


Activities

Links


Experimenter Effects

Introduction

Measures need to be taken to make sure that the researcher's personal expectations don't unduly influence the results of the study.

Key Concepts Explained:

Here are some of the ways in which experiementers keep expectations from influencing the results of the study:



Activities
Links

wwwlink: How various biases can make people think bogus therapies work.
wwwlink: Facilitated Communication exposed in double-blind studies.
wwwlink: Experimenter Bias in Hypnosis Performance.



Conclusion

If the steps outlined in this section are done correctly, researchers can make conclusions about cause and effect relationships between variables.

Limitations to the Experimental Method


Comparison of the Different Methods:



......................................Interactive Table:
Research Methods in Psychology: Advantages and Disadvantages

Click on Method Name to Jump to the section that describes method in greater detail.

Method   Advantages Disadvantages  
         
Case Study   Good Source of hypotheses. Individual may not be representative or typical.  
    Provides in-depth information on individuals. Difficult to know which subjective interpretation is best.  
    Unusual cases can shed light on situations or problems tha are unethical or impractical to study in other ways. Allows researcher little or no control of the situation.  

Naturalistic Observation   Allows description of behavior as it occurs in the natural environment. Observations may be biased.  
    Often useful in first stages of a research program. Does not allow firm conclusions on cause and effect.  

Laboratory Observation   Allows more control than naturalistic observation. Allows researcher only limited control of the situation.  
    Allows use of sophisticated equipment. Observation may be biased.  
      Does not allow firm conclusions on cause and effect.  
      Behavior in the laboratory may differ from behavior in the natural environment.  

Test   Yields information on personality traits, emotional states, aptitudes, abilities. Difficult to construct tests that are valid and reliable.  

Survey   Provides largest amount of information on large groups of people. If sample is nonrepresentative or biased, it may be impossible to generalize from the results.  
      Responses may be inaccurate or untrue.  

Correlational Study   Shows whether two or more variables are related. Does not permit identification of cause and effect.  
    Allows general predictions.    

Experiment   Allows researcher to control situation. Situation is artificial, and results my not generalize well to the real world.  
    Permits researcher to identify cause and effect. Sometimes difficult to avoid experimenter effects.  


Next Topic
- Evaluating the Findings