Heuristics and Biases in Audience Decision Making 239recommend to a younger brother or sister. They were also asked to rate the importance of all the
attributes or decision criteria mentioned in the paragraphs. When making their decisions, the
students discounted the slot values of the unique attributes despite claiming they believed that
information to be important.^377
When a format makes it too diffi cult for audiences to compare alternatives along a commondimension or decision criterion, they may discount that dimension regardless of its importance
to them. An unusual format, recommended by National Academy of Sciences in 1996, displayed
automobile safety information in a way that made it hard for consumers to compare the safety levels
of new vehicles. As a result, consumers did not give safety data the weight it deserved. Instead, con-
sumers gave undue weight to less relevant but easier-to-compare information such as a car’s color
and style. Consumers make better decisions when displays of safety information use meaningful
symbols such as letter grades or stars that make comparing safety ratings easy.^378
Some consumers have developed strategies for avoiding the common dimension effect. Whenmaking choices between comparable products (e.g., two toasters), consumers can easily compare
slot values for the concrete attributes of the products, for example, the number of settings on each
toaster. But some products have few concrete attributes in common (e.g., a toaster and a smoke
detector). To choose among noncomparable products such as these, many consumers have learned
to rise to a higher level of abstraction where they can identify different slot values on common
dimensions.^379 For example, consumers might compare their need for a toaster versus their need for
a smoke detector.
The Asymmetric Dominance Effect: The Impact of a Third Option
Audiences fi nd it easier to make trade-offs between two equally desirable alternatives if given a
third alternative whose slot values are clearly inferior to one alternative but not to the other. The
presence of a third alternative gives audiences a compelling reason to choose one alternative over
the other and is known as the asymmetric dominance effect.^380 For example, when students were given
a choice between $6.00 in cash and a nice pen, 64% chose the money and 36% chose the pen.^381
But when students were given a choice between $6.00, a nice pen, and a cheap pen, only 52%
chose the money. Forty-six percent chose the nice pen and the remaining 2% chose the cheap
pen. Because comparing two pens is easier than comparing a pen to cash, an additional 10% of the
students chose the nice pen.
The Limited Options Bias: The Appeal of Yes or No Choices
Providing audiences with too many alternatives, and thus with too many schema slot values to
integrate easily, can stop them from making a decision. For example, employees’ participation in
401(k) plans dramatically drops as the number of funds their employer allows them to choose
from increases.^382 Experienced physicians are less likely to prescribe a new medication if they
are asked to choose between two medications than if they are asked whether to prescribe a single
medication.^383
In an often-cited study of consumer decision making, grocery store shoppers were offered theopportunity to taste any of six jams at one booth, or any of 24 jams at another. At the six-jam
booth, 40% of shoppers stopped to taste and 30% who tasted purchased a jam. At the 24-jam booth,
60% stopped to taste but only 3% who tasted purchased.^384 Similar effects have been shown for
other types of products,^385 for loan offers,^386 and for retirement plans.^387 When, under large choice
set conditions, the audience does make a decision, it tends to select predefi ned default options.^388
The audience also exhibits more disappointment and regret.^389