Persuasion is the ability that some people have to transmit ideas, and that these are finally shared, accepted and spread by the receiver of the message.

Thus, persuading implies the ability to convince others, and is a tool that is used especially in the field of advertising, sales and marketing.

The Model of the probability of elaboration was created by Petty and Cacioppo (1983,1986) and addresses the issue of persuasion, within social and organizational psychology.
It tries to explain how people are persuaded, and in what way. Let’s see what it consists of.

Processing probability model: characteristics

The model of the probability of elaboration was a milestone in persuasion studies, since it integrated the previous models of attitude. Its objective was to create a model that grouped together the contributions of previous persuasive theories .

The theories that the model of the probability of elaboration brings together are: the Yale theory of communication based on the sequence: source, message, channel and receiver, McGuire’s theory (1968), the contributions of implication (Krugman, 1966), the theory of social judgment (Sherif et al., 1981), the heuristic model (Chaiken, 1980) and, to a lesser extent, the value expectation models (Ajzen, 1975).

It was in the 1980s (in the decade of its creation) that the model of the probability of elaboration was empirically demonstrated. This was done from the study of advertisements, which were used as experimental stimuli .

Although 30 years have passed since the model appeared, it is still applied for different researches, as for example in the study of persuasion on the Internet.

Components: aspects of persuasion

There are four central ideas or components in Petty and Cacioppo’s model of the probability of occurrence.

1. Continuum

People’s attitudes and other judgments can be modified to varying degrees , through a continuum of elaboration, from “low” to “high”. In other words, their beliefs can be modified in a slight or intense way, including the intermediate points.

2. Specific processes of change

Along this continuum various specific processes of change can occur .

For example, a classic conditioning or a simple exposure (effect of mere exposure), occurs when the required thinking is low or not very elaborate . These processes will be situated at the low end of the continuum.

In contrast, models of cognitive response and value expectation are produced when a high degree of thinking is required (more complex thinking, which requires greater cognitive effort). These will be situated at the high end of the continuum.

2.1. Routes

At the brain level , two types of routes exist and are used: peripheral and central.

2.1.1. Peripheral route

A peripheral route is followed when the processes involved are at a low level of the continuum. This route focuses on peripheral aspects of the message , i.e. less important aspects, details, etc.

Following a peripheral route implies little involvement by the recipient, less mental effort and short-term changes in their attitudes .

2.1.2. Central route

In contrast, a central route is followed when the processes involved are at a high level of the continuum.

This route implies greater involvement and mental effort on the part of the receiver, who focuses on more central and elaborate aspects of the message, as well as lasting changes in their attitudes (in the long term).

2.1.3. Complementarity of routes

The fact of finally persuading the receiver is determined by a mixture of the two processes; that is, there is no separation or dichotomy , but both processes complement each other according to the characteristics of the message and other variables.

3. Consequences of the trial

The result of the processing levels (whether high or low), will determine the consequences of the receiver’s judgment . That is, if the judgement is based on thinking about the merits (the merits of what the sender wants to persuade us about), there is a greater chance that such a judgement will persist over time, better resist attempts at change and generate consequences for other judgements and behaviours.

The model of the probability of processing, according to the variables that can affect the attitude of the recipient, organizes several specific processes.

For example, the attractiveness of the source or the emotion felt will influence the amount of thought a person has by placing it at a point on the continuum further up or further down.

However, if circumstances have previously placed the person at the low level, the variables can serve as simple keys, affecting attitudes in a direction that is consistent with their validity.

Conversely, if the person is at the high end of the continuum, there are three other ways in which the variable can affect judgments:

  • By argument or evidence ; for example, the attraction or the emotion felt
  • Affecting the validity of the thoughts that come to mind, e.g., more positive thoughts,
  • Affecting structural factors of the thoughts generated; for example having more confidence towards one’s own thoughts.

Model variables

There are several variables in the processing probability model , which determine how the message will be processed and whether persuasion will finally occur:

  • Motivation for processing / Need for information
  • Processing capacity.
  • Depth of thought processing.
  • Positivity of the cognitive response.

Bibliographic references:

  • Petty, R. and Cacioppo, J. (1983). Central and peripheral routes to persuasion. In: Percy, L. and Woodside, A. (eds). Advertising and consumer psychology. Lexington Books, Mass.
  • Stiff, J. (1985). Cognitive processing of Persuasive Message Cues. A Meta Analytic Review of the Effects of Supporting Information on Attitudes. Michigan: Michigan State University.
  • Hogg, M. (2010). Social psychology. VAUGHAN GRAHAM M. PANAMERICANA, Editorial: PANAMERICANA
  • León, J.J. (2014). Validity and extensions of the processing probability model (ELM). For a persuasive field theory in advertising. adComunica. Journal of Strategies, Trends and Innovation in Communication, 8.