Persuasive Communication - How Audiences Decide. 2nd Edition

178 Understanding Rational Decision Making

a mortgage and are more likely to select higher risk, adjustable-rate mortgage products than when

they have only a few properties to evaluate.^361 Information overload may also explain the effective-

ness of sequential infl uence tactics such as the “Foot-in-the-Door” technique. Responding to an

initial request of a “Foot-in-the-Door” technique depletes the audience’s cognitive resources and

makes it more diffi cult for them to refuse subsequent requests.^362 Having too many alternatives or

benchmarks to compare can even impair experts’ ability to make good decisions. For example, the

accuracy of bankers’ bankruptcy predictions decreases when they have to compare more than two

years of benchmark data along fi ve or more attributes.^363

In some cases, however, experts prefer to have a large number of alternatives to choose among.

Expert audience members with predefi ned attribute preferences are more likely to prefer a larger

number of alternatives to choose among than novices without such preferences.^364 Unlike novice

investors, expert investors are actually less likely to invest when given just a few investments from

which to choose.^365

A Slightly Larger Number of Attributes

Decision quality may also decrease as the number of attributes or decision criteria increases.^366 The

study of prospective home buyers described in the previous section not only varied the number of

alternative houses but also varied the number of attributes that described each house from 5 to 25.

Buyers reported experiencing information overload and made signifi cantly fewer optimal choices

when the number of house attributes reached 15. The author concludes that when buyers face too

many alternatives or attributes, they can no longer make all of the comparisons necessary to rank

the alternatives accurately.^367

A meta-analysis of bankers making bankruptcy predictions fi nds that even a moderate increase

in the number of attributes, e.g. an increase from fi ve to six or seven, can hinder decision quality.^368

Similarly, when attribute information about products increases, consumers make poorer quality

decisions and are more likely to choose on the basis of the products’ popularity.^369

Two studies of consumers choosing among various brands of laundry detergents, rice, and pre-

pared dinners come to a somewhat different conclusion. Although consumers’ accuracy decreased

as the number of alternatives they considered in a product category increased, in these studies con-

sumers’ accuracy increased as they considered more attributes about each alternative. How many

attributes or decision criteria are too many depends in part on the amount of time the audience has

available for decision making.^370

The Complete Set of Slot Values for Each Alternative

Although audiences tend to use whatever comparative information is made available to them, they

make few additional comparisons on their own.^371 A study of consumers reading ads fi nds that 75%

of those who read comparative ads made comparisons among products whereas only 10% of those

who read noncomparative ads did so.^372

Alignable differences, for example the price of one item versus the price of another, drive the

comparison process.^373 Consequently, comparative ads tend to be more effective than noncom-

parative ads only when they allow different products to be compared along the same attributes.^374

However, a noncomparative ad can change consumers’ attitudes if it enables them to compare

information they previously acquired about a product’s attributes with new and different informa-

tion about those same attributes.^375 For example, weight-conscious consumers would likely change

their minds about a soft drink they thought had 250 calories per serving if they read an ad stating

that each serving had only 90 calories instead.