Elaboration probability model (central vs. peripheral route)

The Elaboration Likelihood Model (ELM), proposed by Petty and Cacioppo, is an influential theory that explains how people process persuasive messages and how this affects attitude change.

It postulates that there are two main routes to persuasion: the central route and the peripheral route, and the choice of one or the other depends on the individual's motivation and ability to elaborate, or think critically, about the message.

The Central Route to Persuasion

The central route is activated when people are motivated and have the ability (time, knowledge, absence of distractions) to think carefully about the content and arguments of a persuasive message.

In this route, attitude change occurs if the arguments are sound, logical, and convincing.

Attitudes formed or changed through the central route tend to be stronger, more resistant to future change, and more predictive of long-term behavior.

This is because the person has invested significant cognitive effort in processing the message.

The Peripheral Route to Persuasion

The peripheral route is taken when people are not motivated or capable of carefully analyzing the message's arguments.

Instead of focusing on the quality of the content, they rely on peripheral cues or heuristics, which are more superficial aspects of communication.

These heuristics might include the credibility or appeal of the source (e.g., "if an expert says it, it must be true"), the length of the message (a longer message may seem more convincing, even if it isn't), the emotional reaction it elicits, or the presence of consensus ("if enough people believe it, it must be true").

Attitudes formed or changed through the peripheral route tend to be weaker, more susceptible to change, and less predictive of behavior.

Factors That Determine the Route

The likelihood that a person will elaborate a message (i.e., take the central route) depends on two main factors:

• Motivation: How relevant is the topic to the person? If the topic i