Persuasive Communication - How Audiences Decide. 2nd Edition

(Marvins-Underground-K-12) #1
Cognitive Processes in Audience Decision Making 129

consumers to consider one attribute of the alternatives presented to them—such as the healthi-


ness of an apple, an orange, and a candy bar—increases vmPFC activity for the attribute and the


weight the consumers give the attribute, and in this case, the healthiness of their choices.^233 When


consumers decide among different types of alternatives—such as food, clothing, and money—the


vmPFC transforms attribute information about each alternative into a common currency in which


all the options can be compared and evaluated.^234 Patients who suffer from bilateral lesions of the


vmPFC have great diffi culty making decisions, especially when choosing among alternatives with


uncertain outcomes.


In the integration stage, the vmPFC passes on the values it computes to two other brain regions

for comparison: the dorsomedial prefrontal cortex and an area in the parietal lobe (see Figures 3.4


and 3.5, p. 108).^235 A third region involved in the information integration process is the right


dorsolateral prefrontal cortex (dlPFC). Repetitive transcranial magnetic stimulation applied to the


right dlPFC diminishes the activation of that area and also that of the vmPFC and consistently


changes the choices people make.^236 Damage to these two regions causes dramatic impairments to


decision making, especially to multi-attribute decision making.^237


The Conversion of Cardinal Numbers Into Ordinal Numbers and Scale Values


When audiences make decisions they generally do not mentally represent the values that fi ll the


slots in their schemata as cardinal numbers (e.g., a price of $5,367,892.00) but represent them as


ordinal numbers (e.g., “third highest priced”) or scale values instead.^238 The think-aloud study


described earlier of a bank’s trust investment offi cer making investment decisions for clients found


that the trust offi cer tended to convert the cardinal numbers in the fi nancial reports into scale values


before comparing them. The study’s author then incorporated this fi nding into a computer model


he developed and simulated the trust offi cer’s investment decisions by fi rst converting numerical


data for each attribute or decision criterion into a three-value scale: Below , equal to, or above.^239


Research fi nds that hospital patients also spontaneously transform numerical information about

the risks of medical procedures into scale values.^240 Consumers make similar transformations when


deciding among products and assign a scale value to each attribute of the recommended product


during the valuation stage of the information integration process.^241


Compensatory vs. Noncompensatory Choice Rules


Many different choice rules for integrating values have been observed.^242 The two basic types of


choice rules audiences use to integrate attribute values are called compensatory choice rules and non-


compensatory choice rules. When audiences use compensatory rules, they make trade-offs and accept


a low value on one attribute or decision criterion in order to get a high value on another attribute.


For example, a car buyer may accept fewer miles per gallon in order to get an increase in safety. Such


rules require the same attributes be examined for each alternative. Examples of compensatory rules


include the weighted additive rule and the equal weight rule , both of which rely on alternative-based


search.


When audiences use the weighted additive rule, they evaluate each alternative one at a time.

For each attribute or decision criterion of the alternative under consideration, they multiply the


attribute’s weight by the attribute’s value. Next they add all of that alternative’s weighted attribute


values together in order to produce an overall value for that alternative. They repeat the process for


each alternative. Then they compare the overall values of all the alternatives and choose the alterna-


tive with the highest overall value. Audiences go through a similar process when they use the equal

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