Six Kinds of Jelly Beans This article - "Six Kinds of Jelly Beans: How the Perception of Variety Influences Consumption" on Knowledge@Wharton (free registration reqd) discusses how visual perception of activity and an abundance of choices ultimately increase consumption.
The normal economic model would be that you eat when you are hungry or that you buy things that you need and that you don’t buy things that you don’t need. But we don’t think people really know how to eat today – they look for cues. And most people don’t realize that an assortment of a product encourages them to take more. We are all mindlessly making a lot of decisions.
A very interesting study.