Exemplar Study: Smells Like Clean Spirit (Two-group Design/Simple Experiment)

In three studies, the authors examined unconscious influence of smell on behavior. Study 3 used a two-group design to examine the direct effect of citrus scent (exposed vs. nonexposed) on cleaning-related behaviors. The judges recorded the frequency of participants’ crumb removal while eating.

Holland, R. W., Hendriks, M., & Aarts, H. (2005). Smells like clean spirit: Nonconscious effects of scent on cognition and behavior. Psychological Science, 16, 689-693. doi:10.1111/j.14679280.2005.01597.x

Discussion Starters:
• What are the design elements (independent variable [IV], and dependent variable [DV]) and operational definitions?
• What are the potential confounds?
• What are the strengths and weaknesses of the study design?
• In what situations might you smell cleaning fluids? Generate ways in which this could influence your behavior.
• Could the activation of other senses (touch, taste, sound, sight) influence behavior and in what ways?
• What other ways could one measure cleaning-related behaviors (observational and nonobservational)?
• Why is inter-rater reliability an important consideration in studies relying on observations?

In-class Activities:
• Ask the class for other contexts where smell could influence behavior. Pick one of the examples given by the class, and then as a class or in small groups, generate a study to test the idea. Suggestions in case students get stuck: smelling Cinnabons in the mall and buying behavior, smelling coffee and feeling energetic, smelling a campfire and wanting to roast marshmallows.
• To address inter-rater reliability, bring in biscuits and have two students (or two per group) randomly assigned to engage in clean versus messy behavior as defined in the assigned article. Others in the group or class should code their behavior and determine inter-rater reliability. Follow up by asking the class if it would be more accurate to just count the crumbs left behind.

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