Persuasive Communication - How Audiences Decide. 2nd Edition

120 Understanding Rational Decision Making

readers are told they will read a particular genre, they will activate a schema of that genre that will

guide their interpretation of the text.^159

Other types of schemata are used to comprehend objects. Figure 3.9 is a depiction of a schema

for comprehending a mechanism, in this case a fl ywheel.^160 The slots in the mechanism schema

have been fi lled in or instantiated with information from the expository passage following it. This

schema enabled a computer model of a human reader to comprehend the expository passage and

to answer questions about it.

Depending upon which schema a reader activates, the same text can be comprehended in differ-

ent ways.^161 In a fascinating study of schema effects on reader recall, cognitive scientists asked one

group of readers to assume the role of thieves and another group to assume the role of prospective

home buyers. The scientists hypothesized the two groups would activate two different schemata.

They then asked both groups to read a brief story about a very expensive house. The “thieves”

recalled the valuable items described in the story that could be stolen from the house. The “home

buyers,” on the other hand, remembered information related to the quality of the house.^162

In a study of schema effects on viewer recall, viewers watched a video of two men walking around

in a room talking about drug use, the police, and theft. Before watching the video, viewers had been

primed with one of three schema-inducing ideas: two burglars; two students waiting for a friend;

or two friends attempting to conceal illegal drugs. Viewers primed with the two-burglars schema

recalled more theft-relevant objects and comments from the video than those in the other two con-

ditions. However, the two students and two friends conditions did not produce signifi cant results.^163

The Schema Activation Process

How do audiences activate the appropriate schemata? When readers begin reading a passage, they

hypothesize that the grammatical subject of the fi rst or second sentence in the passage is its topic.

They then activate a schema for the topic of that grammatical subject.^164 In one study, readers were

FIGURE 3.9 A Mechanism Schema Filled With Slot Values From the Passage Following It

Source: Adapted from Thibadeau, Just, and Carpenter (1982)

Slot name Slot value

Name Flywheel

Goals To store energy

Principles Faster spinning stores up more energy

Physical properties Made of fi berglass and rubber

Physical movements Spinning

Made by Humans

Used by Humans

Exemplars Car engine fl ywheels

Flywheels are one of the oldest mechanical devices known to man. Every internal-combustion engine contains a small

fl ywheel that converts the jerky motion of the pistons into the smooth fl ow of energy that powers the drive shaft.

The greater the mass of a fl ywheel and the faster it spins, the more energy can be stored in it. But its maximum

spinning speed is limited by the strength of the material it is made from. If it spins too fast for its mass, any fl ywheel will

fl y apart. One type of fl ywheel consists of round sandwiches of fi berglass and rubber providing the maximum possible

storage of energy when the wheel is confi ned in a small space as in an automobile. Another type, the “superfl ywheel,”

consists of a series of rimless spokes. This fl ywheel stores the maximum energy when space is unlimited.