Professor Wansink is a professor of marketing in the MBA program at the University of Illinois.

Open your kitchen cupboard and peer into the very back. Behind the boxes of cereal, the cans of soup, and the jars of jam, what do you find? Chances are you will discover several items that you purchased ages ago and which have been sitting there untouched ever since.

Brian Wansink, a professor of marketing in the MBA program at the University of Illinois, recently conducted a study to answer the question: Why do people spend money on products that they never use?

"For an individual consumer, the money and effort spent purchasing these products is not trivial — as many as 12 percent of purchased products are never used and eventually discarded. By understanding why we buy products we never use, we can change our purchase and usage habits to reduce product abandonment, thereby saving money and reducing waste," said Wansink in the foreword to his study.

In a random sampling, Wansink surveyed 412 homemakers in five states, sending them a list of questions that centered around three main queries: Why do people buy but never use products, why don't they use these items and how do they dispose of them?

Upon analyzing his data, Wansink was very surprised to find that the predominant reason for buying what he terms "abandoned" or "castaway" products was not due to advertising and marketing schemes. In fact "marketing-related factors only account for 16 percent of unused items," said the report.

Instead, consumers most commonly purchased abandoned products with a specific purpose in mind. "People use products when they are motivated to do so, and when they have the ability to do so, and when they have the opportunity to do so. If all three conditions are not met, the product is not consumed," said Wansink's report. For instance, someone may have bought a product for a recipe, to remove stains for a holiday or other special occasion. These three reasons account for 63 percent of abandoned items.

In answer to the question of why a product was never used after being purchased, most respondents said that the purpose for which the item was bought never actually arose, such as ingredients bought for recipes that were never made. Other respondents claimed they had "abandoned" certain products because they were inconvenient, as in too complicated or too time-consuming to prepare.

A significant percentage of participants claimed that they had not used a product because they did not like it. For instance, they may have bought a large jug of salad dressing, tasted it, not liked it, and yet kept it, thinking that one day maybe someone else — a guest perhaps — would come along and consume the remainder.

When asked how they planned to dispose of their abandoned products, more than 50 percent said that they would throw the items away rather than keep it or donate it to a food bank. Follow-up interviews revealed that this initially discouraging result could actually be attributed the fact that "it would be inappropriate to give remaining portions of an unused product to a food bank if the product had already been opened," said Wansink.

Those consumers that chose to keep their products did not intend to make any special effort to employ it in the near future, but rather opted to wait until an opportunity for use naturally arose sometime in the future.

Since "abandoned products represent a significant amount of waste," said Wansink, the professor offers ideas for modifying how consumers purchase, use and dispose of the household and food items that they buy. These suggestions are intended to make consumers more aware and to help them reduce the money and resources wasted on unused products.

• Buy substitutable products whenever possible. For example, if a recipe calls for either canned corn or canned okra, buy corn, which is the more versatile product.
• Purchase "specific-use" items as close to the usage date as possible. This helps reduce the chance that your plans to use it will not change between the time of purchase and the time of use.
• Only buy multi-packs of non-versatile products if all of it will be used shortly after purchase. While multi-packs of products offer per-unit savings, those savings are only realized if the entire product is used. In other words, buying a four-pack will not save you money if two of the packages are never used.
• Rotate products from the back of the shelf to the front during cleaning.
• Remember the saying, "Month 24, keep no more." While the average age of castaways in the study was almost three years, some products will have expired by then, and therefore should be thrown away.
• Actively plan new uses for abandoned products. One option for castaway foodstuffs is to use cookbooks that have food indices in the back. This forced versatility method is very effective.
• If the product cannot be used and has not expired, give it to a food bank.