Source: Laboratories of Gary Lewandowski, Dave Strohmetz, and Natalie Ciarocco—Monmouth University

In any experiment researchers have the challenge of creating experiences for participants that are consistent (i.e., reliable) and authentic (i.e., valid). Yet there are many ways to manipulate any one variable. For example, if you want participants to feel sad, you can have them think of their own sad memory, watch a sad video, or read a sad story.

Researchers must find the best way to operationalize a psychological construct in order to produce the most effective manipulation possible. Often, before running the main study, researchers will pilot test (i.e., try out) their manipulations to check their effectiveness.

This video demonstrates how to operationalize the same independent variable (acute stress) in three different ways. Specifically, this study seeks to identify the best sound (static, ticking clock, or crying baby) to play during a difficult task (solving complex math problems) to optimally manipulate stress.

Psychological studies often use higher sample sizes than studies in other sciences. A large number of participants helps to ensure that the population under study is better represented and the margin of error accompanied by studying human behavior is sufficiently accounted for. In this video, we demonstrate this experiment using just three participants, one for each condition. However, as represented in the results, we used a total of 120 (40 for each condition) participants to reach the experiment’s conclusions reflected in the Results section.