Can a one-second glance at a group of products reveal its average price—and make that average seem higher?

Details

Supermarkets and department stores display products in groups, such as stacks of produce, cans of food, and racks of clothes. The researchers asked whether people viewing these displays can evaluate a group's price as a whole, or instead search through it and assess individual objects. Efficiently evaluating a group's overall price could be useful for strategic shopping, guiding the search for particular objects, and forming preferences.

In an experiment testing ensemble price sensitivity—the ability to judge the price of a group—20 participants first estimated the prices of individual products from two major retailers. Their estimates showed high inter-rater reliability, meaning observers agreed closely, and correlated highly with the retailers' listed prices.

The researchers then created groups of 6 objects drawn from those rated products and displayed the groups to new, independent participants for 1 second. These participants reported the perceived average price of each group. The group-price estimates correlated highly with the average prices calculated from independent observers' single-product estimates.

The findings were robust across spatial and temporal group displays and across stimulus sets containing a variety of price ranges. Participants integrated several objects into their group-price estimates, supporting the finding that visual impressions of value reflected a summary statistical representation. However, ensemble coding also biased price evaluations: the perceived price of the groups was higher than the average of the individual items.

Previous research had investigated price evaluations when consumers had time to deliberate about product value. These results suggest that ensemble perception operates at a consumer's first glance and can affect their initial impression of product displays.

This was a meeting abstract presented at VSS 2016.