By Marie Komori

Published in the Journal of Personality and Social Psychology in 2007, Ying Zhang, Ayelet Fishbach, and Arie Kruglanski conducted six studies on how additional reasons, or arguments, for an action can undermine the perceived effectiveness of the action’s purpose. In what they call the Dilution Model, having multiple arguments for a behavior may maximize gains from that behavior, but multiple arguments may also decrease the strength of, or “dilute,” the association between the arguments and the goal of the behavior, and therefore reduce the instrumentality of the behavior. In applying this concept to my research on reducing meat consumption for the benefit of the environment (in terms of energy use and emissions produced), according to the Dilution Model, having multiple arguments for reducing meat consumption may reduce the instrumentality of the goal – in this case, benefiting the environment.

I have applied the Dilution Model to my research by measuring the difference in effectiveness of arguments when either one or two arguments were presented for reducing meat consumption. I also took into account the nature of the arguments and whether the similarity of these natures affected the effectiveness of the arguments. For example, if two arguments of the same nature (e.g. environment) for reducing meat consumption are presented, does the persuasiveness of the two arguments “average out” or “stack up”? I hypothesized that the effectiveness of two, homogeneous arguments would “stack up,” while two, heterogeneous arguments (e.g. environment and health) would “average out.” Furthermore, I hypothesized that when two arguments “averaged out,” the effectiveness would be similar to the effectiveness of each arguments by themselves. Therefore, I expected that multiple, heterogeneous arguments would be more effective than multiple, homogeneous arguments as well as single arguments, where the “effectiveness” of arguments were defined as the participants’ perceived persuasiveness of the arguments and behavioral intent to reduce meat consumption.

 The results from the most recent design of this research showed mixed results in that the expected trend was present, but with insignificant differences between the effectiveness. When analyzing the data, I also took into account participants’ prior knowledge of the arguments: the expected trend was present among participants with no prior knowledge. In light of these results, I will conduct one more design of this research in which I will present 3 homogeneous or heterogeneous arguments for reducing meat consumption. The nature of the arguments will consist of environmental, health, and animal welfare. My hope is that the difference between single and three arguments will be more emphasized than before where I presented one or two arguments.