ScienceDaily (June 13, 2009) — We judge probability and make risk judgments all the time, such as when we try new products or consider which stocks to trade. It would seem that our decisions would be rational and based on concrete factors; however, we are not always so pragmatic.

Some judgments are not based solely on relevant information but can be influenced by subjective beliefs. For example, most of us would probably cringe at the thought of drinking a sugar solution that was labeled "sodium cyanide," even if we knew it was perfectly safe to drink.

According to new research by consumer psychologists Arul Mishra and Himanshu Mishra from the University of Utah and Dhananjay Nayakankuppam from the University of Iowa, something as mundane as how objects are grouped together can have a significant impact on the decisions we make.

Volunteers selected a mug from one of two groups. In one group, the wrapped-up mugs were spaced far apart, while in the other group they were closer together. Some of the volunteers were told that one of the mugs was defective while the other volunteers were told that one of the mugs contained a gift coupon.

The volunteers who were told that one of the mugs contained a gift coupon selected from the mugs which were close together. Conversely, the volunteers who were informed that one of the mugs was defective chose from the group of mugs that were spaced far apart.

The researchers then performed a follow-up experiment: volunteers had to choose among ketchup bottles (as before, the bottles were in two groups, close together or spaced farther apart). This time, some of the participants were told that either one or three of the bottles had defective lids, while the remaining participants were told that either one or three of the bottles contained gift coupons. It turns out that the volunteers who were told that three of the bottles had defective lids were the most likely to choose from the spaced apart group and the volunteers who thought that three of the bottles contained gift coupons were the most likely to choose from the closely spaced group.

These results, reported in Psychological Science, a journal of the Association for Psychological Science, reveal that we tend to view products that are grouped close together as being "contagious." It appears that if one of the products has a prominent good or bad quality, we will see that quality as spreading among other objects which are close by, a phenomenon known as the "group-contagion effect." As the authors noted, these findings suggest that people tend "to choose from groups of closely arranged products in the gain domain and from groups of widely spaced products in the loss domain."

Journal reference:

1. Mishra et al. The Group-Contagion Effect: The Influence of Spatial Groupings on Perceived Contagion and Preferences. Psychological Science, 2009; DOI: 10.1111/j.1467-9280.2009.02371.x

Related Stories

Search ScienceDaily

Finding Double Stars