Course Content  

Lab-1: Experimental Design (18 Points)

Each year, psychologists across the world publish thousands of research articles in professional, scientific, peer reviewed journals.  What is meant by "peer reviewed" is that the researcher, after completing a research project, submits the written summary of the completed research to a review panel for a scientific journal (like The Journal of Experimental Psychology, Journal of Abnormal Psychology, American Psychologist, etc...).  The panel scrutinizes the scientific validity of the methodology used in the research, and either approves it for publication or rejects it and send it back.  The process is a way of filtering out research that was is weak in its methodology and therefore questionable in value.

In past semesters, students were required to read an actual scientific journal article and write a review of the article.  However, for this activity, you will be required to use your imagination and design your own piece of research.  You will not be required to actually gather participants and run your study, but rather put thought into designing the beginnings of a well constructed study.

Designing Your Own Experiment

Step 1: 

After reading about research methods in Chapter 2 your new knowledge of experimental design will now be put to the test.  For this lab activity, you will design your own experiment.  This is a critical thinking exercise that requires knowledge of how experiments work and some creative imagination.  

Keep in mind that you DO NOT need to actually gather participants and run the study.   

Choosing Your Variables

For your study, you will need to choose an independent variable (something you suspect will cause a change in the dependent variable) and a dependent variable (something you suspect will be changed by the independent variable).  The table below lists some suggested variables you might choose, but you are not limited to using these.  Be creative.

The variables above are not necessarily meant to be matched left to right.  That is, don't simply assume that you can only choose to test the effects of alcohol on driving ability.  You can mix and match the variables any way you like.  For example, you might look at the effects of caffeine on reading comprehension or the effects of certain types of music on depression level.  Be creative.

Designing Your Method

After choosing your variables, think about each of the following questions.  

• What type (age, gender, etc...) of subjects will I use?
   
  
• How will I treat the subjects in my experimental and control groups differently?  (Hint:  In good formal experiments, the only difference in the treatment of subjects in the experimental and control groups is that subjects in the experimental group get the independent variable.  Otherwise, they are treated exactly the same.)
  
  
• How will I assign the subjects to either my experimental or control groups? 
  
  
• Will I use a double-blind procedure?
  
  
• Will I use a placebo for the control group subjects?
  
  
• How will I measure change in my dependent variable in a way that is accurate and unbiased?  A test (like a comprehension test or depression test)?  Or will I simply have observers using an operational definition?
  
  
• What other specific controls will you use?  (Hint:  Once again, in good formal experiments, the only difference in the treatment of subjects in the experimental and control groups is that subjects in the experimental group get the independent variable.  Otherwise, they are treated exactly the same.  For example, same room conditions, environmental conditions, time of day, food consumed prior to the experiment, sleep prior to the experiment, etcetera...)

Step 2: 

After designing your fictional experiment, answer the following questions.  Send your answers to the discussion questions through the assignment submission box within the Blackboard/Ce6 platform.  To access the assignment submission box, login to Cougarweb, click the link to this course, select the 'assignments' tab on the left, then click the link to 'Lab-1: Experimental Design Lab."  

Submit your answers to the discussion questions by the deadline specified on the Course Content page, or Blackboard Assignment page.     

1. What is the central hypothesis (expected result) of your study?
   
   
2. What is your independent variable?
   
   
3. What is your dependent variable?
   
   
4. Why did you choose these variables for your study?  That is, explain what interested you in these variables.
   
   
5. Describe your subjects.  Why did you choose these subjects for your study?
   
   
6. How would you assign subjects to either the experimental or control group?
   
   
7. Describe how your experiment would take place.
   
   
8. How will you accurately measure changes in your dependent variable?
   
   
9. Will you use a double-blind procedure?  A placebo?  Explain.  (Because of the variables chosen, some experiments need a double-blind procedure, others don't.  Same with a placebo.)
   
   
10. Describe any other controls you would use to give strength to your design.  (Hint:  "In my study, the experimental and control groups will have the same __________, the same __________, the same __________," etcetera...)
    
    
11. Note any specific weaknesses in your design.  Are there factors or outside variables over which you have no control that might significantly affect the outcome of the study?
    
    
12. Other comments?

Copyright 2002, Collin County Community College District and Dan Lipscomb 
All material on this site is for CCCCD class use only. Any unauthorized duplication or distribution is prohibited.