Applications
Marketers can take advantage of rational ignorance by increasing the complexity of a decision. If the difference in value between a quality product and a poor product is less than the cost to perform the research necessary to differentiate between them, then it is more rational for a consumer to just take his chances on whichever of the two is more convenient and available. Thus, it is in the interest of the producer of a lower value product to proliferate features, options, and package combinations until the average shopper finds it too much trouble to make an informed decision.
This also works for politics. By increasing the number of issues that a person needs to consider in order to make a rational decision between candidates, they can level the playing field by encouraging single-issue voting or party-line voting.
Another, more nuanced, political application involves a voter's identification with a political party, much like the adoption of a favorite movie critic. Based on prior experience a reasonably responsible voter will find politicians or a political party that will draw conclusions similar to their own conclusions when the voter had the time to do the analysis.
Read more about this topic: Rational Ignorance