Orangeville, ON (Caroline Davis) To some marketers, promoting a product without a bonus is ill-advised. They assume the product has a certain value. By bundling a bonus with the product that value increases. How could it not?

Two decades of psychological studies have reached an interesting conclusion. If consumers feel the bonus is not relevant, then the bundle’s perceived value and appeal drop. A similar result occurs if the bonus is cheap. Often the original item on its own will have the best value.

As an example, consider a GPS unit that comes with a chance for a free trip to Las Vegas. You might think it should sell more often than the GPS by itself. But think about homebodies or those who despise Las Vegas. They should understand that the GPS itself is worth the same, regardless of the bonus.

Not so. The bonus can prompt shoppers to bypass that GPS altogether. They fail mentally to cancel the irrelevant or unwanted bonus. Many consumers average the major item and the bonus. Hence an unwanted Las Vegas trip or a $1 scratch card as a bonus would lower the perceived value of the GPS.

How tricky is the human mind!