Psychology journal entry 2 Identifying and Manipulating Variables

A key factor in the effectiveness of an experiment is the accurate and skillful identification and manipulation of the variables. The first step factor that changes because of what happens to another factor. For example, a doctor in a large medical practice with two waiting rooms noticed that the patients who waited in room A showed a greater level of anxiety than those who waited in room B. The rooms were about the same size and were decorated identically. To discover the source of the raised anxiety, the doctor conducted an experiment. She identified the dependent variable as the level of patient anxiety after waiting. Next, she thought of differences between room A and room B that might affect the dependent variable. She listed the temperature of the room, the presence of a television set, and a clear view of the laboratory across the hall. These factors are independent variables; they operate independently of each other or any other factors. The independent variables must be tested one at a time. To identify the dependent variable, which is the To accurately identify cause-and-effect relationships, one independent variable is tested while the others remain constant. In the doctor's experiment, she first tested the temperature by adjusting the thermostats so that room A's temperature exactly matched room B's. When there was no change in patient anxiety levels, she returned room B's temperature to its previous level and removed the television set. Again, there was no change in patient anxiety. She returned the television set and had the clear glass door to the lab replaced with one of frosted glass. Patient anxiety dropped. The doctor had identified the independent variable that affected patients while they waited for treatment.
Thinking Skills: Read each situation below and answer the questions that follow. Tom and Juanita conducted an experiment to test the effect of age on difference threshold in children 5 years of age and younger. They created an experimental setup that included cards mounted with 12 of paint chips of the same hue but of various shades. The difference between the first pair was fairly obvious, but the difference between each subsequent pair decreased. The last few pairs of chips looked almost identical. The process that Tom and Juanita used was to show the pairs to a child and to see the smallest amount of difference the child could detect when asked to identify the darker chip on each card. They tested 3 children from each of these age groups: 2, 2.5, 3, 3.5, 4, 4.5, 5. 1 What is the dependent variable? 2. What independent variable was tested? 3. What unidentified independent variables might have influenced the results? Ronald and his classroom research group were conducting an experiment to test people's ability to touch their noses when their eyes were shut. They were testing their hypothesis that males were more skilled at this task than females. The group also had a theory that noise could alter a person's ability to carry out the task. They asked several classmates and teachers to perform the task. Sometimes, Ronald or someone else in the research group would whistle or shout while a person tried to do the task. 4. What dependent variable did Ronald's group identify? 5. What independent variables can you identify? 6. Were the variables effectively manipulated? Why or why not? 7. How could you improve the experiment? 8. Now construct your own experiment; measuring both dependent and independent variables to determine how a lack of sleep influences performance on a math quiz which emphasizes solutions to word problems. Be sure to address the following elements. (A) What is your hypothesis? (B) Operationally define your variables. (B) What are your independent and dependent variables? (C) How will you conduct your research? (D) What procedures will you use to analyze your results?