When you think of holiday shopping, the least enjoyable is getting bumped by crowds of people, right? Brett A.S. Martin, a professor at Queensland University of Technology Business School in Australia, definitely knows this, since he believes congestion is actually caused by store owners filling their aisles to the brim with as many products as possible.

Martin set up an experiment with volunteers who were instructed to shop as they normally would and then specifically take a look at a purse on display in the middle of the store being used in the experiment.

He also sent in a couple of attractive, 30-year-old “plants” to blend in and then “accidentally” brush up against shoppers who were browsing. What Martin found was that, across the board, anyone who was bumped gave the store a lower rating in the post-experience questionnaire and estimated a lower price for the item on display.

In addition to the low ratings of their experience, every shopper who was bumped also spent less time in the store than those who were not. The results were consistent for every shopper, no matter their gender. Anyone who felt crowded left the store faster, had a more negative experience and valued the merchandise less than those who were not bumped or crowded.

What does this mean? It means that maximizing aisle space to fit in as much product as possible will not necessarily mean more sales, since shoppers feeling crowded will not shop for long or put a high value on what is for sale.