Every day we make choices. Usually, we believe that our decisions are made rationally and fully under our control. However, studies have clearly shown that our minds are influenced by factors beyond our recognition. In fact, it is possible to design systems that guide people to make specific decisions without them even knowing it.
One way this happens is through choice architecture. This is the science of building the system through which the choices are presented. Whether this is a survey, restaurant menu, or car building web site, the order and types of choices can bias the decision maker. It need not be nefarious; it is simply an aspect of the limitations built into all choice architecture designs.
In his book, The Elements of Choice, Eric J. Johnson discusses the field of choice architecture in great detail. One specific example he explores is how placement on a list affects choice.
Lists are a common choice architecture design. No matter if it is a list of three items or three hundred, the placement of items on the list impacts decisions. However, the format in which the list is presented also has an impact. It changes the location on the list where someone would want their preferred choice to be located.
For example, if the list is text only and the reader is in control of where to place their eyes, then the first spot is almost always the most selected. Examples of this type of list presentation are restaurant menus or short option lists, such as election ballots. However, when the decision maker is listening to a list or has no ability to move backward or forward by choice, then the final slot is the most selected. Examples of this are judging competitions that involve artistic merit, or simply having a friend recite a list of potential movies to watch on a weekend night.
This is a key difference. In the first case, people are judging their choices based on the first item presented. It anchors the decision. In the second case, the decision maker is working off memory, which tends to be strained as the list grows longer. This causes the most attention to fall on the later items.
Read more about how choice architecture affects our decisions in The Elements of Choice.