Persuasive Communication - How Audiences Decide. 2nd Edition

Heuristics and Biases in Audience Decision Making 237

Like other heuristic choice rules, “if-then” heuristic choice rules allow the audience to bypass

making trade-offs and avoid the diffi cult weighting and combination processes that are involved in

normative information integration.^358 Although the audience’s heuristic use of “if-then” choice

rules can occasionally yield nearly optimal choices,^359 choices made on this basis are usually inac-

curate. When audiences formulate such rules from their experience, they tend to overgeneralize

from a very small sample.

Audiences can avoid the diffi culties of the information integration process altogether if they

simply choose the same alternative they chose the last time they had to make a similar decision.

Audiences rely on the habitual choice heuristic when they retrieve prior evaluations of their

current options from memory and then choose the option they had previously evaluated most

highly.^360

Trade-Off Avoidance: The Impact of a Dominant Attribute

In many situations each alternative under consideration has both positive and negative slot values

for different attributes or decision criteria. For example, a higher quality product usually comes

with higher cost. But most people tend to avoid making such trade-offs.^361

In a seminal study of trade-off avoidance, consumers were asked to identify pairs of alternatives

that had equal value for them.^362 For example, consumers said Gift Package A, which contains $10

in cash and a book of coupons worth $32, had the same value to them as Gift Package B, which

contains twice the cash but a coupon book worth signifi cantly less.

Gift Package A Gift Package B

Cash $10 $20

Coupon book worth $32 $18

A week later, the consumers were asked to choose between the two alternatives. They were also

asked which decision criterion—cash or coupons—they considered more important. Eighty-eight

percent of the consumers chose the alternative that had a higher value for the criterion the partici-

pant considered more important. Similar results obtain for many different decisions, including choices

among college applicants, auto tires, baseball players, and routes to work. A likely explanation is that

avoiding trade-offs makes it easier for people to justify their choices both to themselves and others.

A similar explanation may account for the tendency of policy makers to neglect mentioning

trade-offs and to avoid arguing the pros and cons of their policy proposals. Instead they tend to

justify their proposals with one-sided arguments to which a simple noncompensatory choice rule

can be applied.^363

The Mere Quantity Effect: The Impact of a Seemingly Dominant Alternative

Audiences can avoid many of the diffi culties of the information integration process if they simply

choose the alternative that is agreed on by the most people. In a study of the persuasiveness of multiple

sources, audience members weighted descriptions of other people’s personality traits more heavily

when the descriptions were presented by multiple sources than when they were presented by a single

source.^364 Another study fi nds that three speakers conveying three arguments are more persuasive

than one speaker conveying the same three arguments.^365 For audiences who lack the information or

expertise to make an informed decision themselves, the greater the number of their advisors and the

fewer the differences among their advisors’ proposals, the greater the persuasive effect.^366