To study the effects of physical discomfort on attention, Dr. Lopez conducted the following study: A group of participants were required to keep one hand submerged in cold water (52 degrees). Half of the participants kept their hand in the water for 2 minutes, and half of the participants kept their hand in the water for 4 minutes. In addition, half of the participants were given a placebo pill and told it would reduce the pain of the water (pain relief assumed). The other half were given a placebo pill and told that it would have no effect (no pain relief assumed). While their hands were in the water, participants engaged in a number of tasks that required attention, with the mean time in seconds of the tasks being recorded (quicker completion meant more attention).
- What are the independent variables in this design?
- State the design using ___ x ___ factorial notation. (see p. 356 of your textbook)
- What is the dependent variable in this design?
- Six possible sets of results are in the tables below. For each set of results, answer the following questions:
- Is there a main effect of discomfort on attention? If so, describe it.
- Is there a main effect of placebo on attention? If so, describe it.
- Is there a discomfort X Placebo interaction? If so, describe it.
Normally, researchers would use a statistical test to determine whether there are main effects or interactions. For the purpose of this assignment, you can use informal, intuitive judgments. You can consider any difference of 20 seconds or more as being “large.” You might find it helpful to graph the results and to use Figure 12.20 in your textbook as a model.
