Two connected papers were published in Judgment and Decision Making last quarter that have great illustrations of the "Nudge" effect I have blogged about many times in the past.
The first study looked at how people take food from salad bars. The salad bar had three rows of 24-oz containers of food. So as you walked down the bar, half of the items were in the front row and half of the items were in the middle row, and then in the way back was a repetition of whatever was in the front row (for people walking down the other side). They moved the items around to see what effect location had. It turned out that just the slight inconvenience of having to reach to the middle row decreased how much of those items were taken. They also looked at whether items were at the beginning of the bar, middle or end. Some things were taken more at each location, so this basically canceled itself out. Finally, they found that customers took less of items that had tongs than items that had spoons. Just the small inconvenience of having to use tongs reduced the amount that people took.
The second study looked at the location of items on a printed menu. They moved the items around the menu to see what effect the location would have. They only looked at one thing, but it was significant. Items at the beginning and end of the menu were ordered more than items in the middle of the menu.
So what does this matter? You could take two approaches:
Maximize profits: put the items with the highest profit margin in the front row of a salad bar and the beginning or end of a printed menu.
Maximizing health: put the healthiest items in the front row of a salad bar and the beginning or end of a printed menu.