What is the Elaboration Likelihood Model and how does it explain the process of persuasion?

The Elaboration Likelihood Model (ELM) is a theory that explains the process of persuasion and how individuals are influenced by different messages. Developed by social psychologists Richard Petty and John Cacioppo in the 1980s, the ELM suggests that there are two main routes through which persuasion can occur – the central route and the peripheral route. This model examines how people process information and the factors that determine whether they will be persuaded by a message. By understanding the ELM, we can gain insight into the different ways people are persuaded and the impact this has on their attitudes and behaviors. In this essay, we will discuss the key components of the ELM and how it provides a framework for understanding the complexities of persuasion.

The elaboration likelihood model (ELM) of persuasion is a model of how attitudes are formed and changed that was developed by R. E. Petty and J. T. Cacioppo in the early 1980s (see also attitude change). Central to this model is the “elaboration continuum”, which ranges from low elaboration (low thought) to high elaboration (high thought). The ELM distinguishes between two routes to persuasion: the “central route,” where a subject considers an idea logically, and the “peripheral route,” in which the audience uses preexisting ideas and superficial qualities to be persuaded.


Central route

Central route processes are those that require a great deal of thought, and therefore are likely to predominate under conditions that promote high elaboration. Central route processes involve careful scrutiny of a persuasive communication (e.g., a speech, an advertisement, etc.) to determine the merits of the arguments. Under these conditions, a person’s unique cognitive responses to the message determine the persuasive outcome (i.e., the direction and magnitude of attitude change). So, if favorable thoughts are a result of the elaboration process, the message will most likely be accepted (i.e., an attitude congruent with the message’s position will emerge), and if unfavorable thoughts are generated while considering the merits of presented arguments, the message will most likely be rejected. In order for the message to be centrally processed, a person must have the ability and motivation to do so.


Peripheral route

Peripheral route processes, on the other hand, do not involve elaboration of the message through extensive cognitive processing of the merits of the actual argument presented. These processes often rely on environmental characteristics of the message, like the perceived credibility of the source, quality of the way in which it is presented, the attractiveness of the source, or the catchy slogan that contains the message.


Choice of route

The two factors that most influence which route an individual will take in a persuasive situation are motivation (strong desire to process the message; e.g., Petty & Cacioppo, 1979) and ability (actually being capable of critical evaluation; e.g., Petty, Wells, & Brock, 1976). Which route is taken is determined by the extent of elaboration. Both motivational and ability factors determine elaboration. Motivational factors include (among others) the personal relevance of the message topic, accountability, and a person’s “need for cognition” (their innate desire to enjoy thinking). Ability factors include the availability of cognitive resources (e.g., the presence or absence of time pressures or distractions) or relevant knowledge needed to carefully scrutinize the arguments. The subject’s general education level, as well as their education and experience with the topic at hand greatly affect their ability to be persuaded. Under conditions of moderate elaboration, a mixture of central and peripheral route processes will guide information processing.


Testing the Elaboration Likelihood Model

To design a way to test the Elaboration Likelihood Model, it is crucial to determine whether an argument is universally seen as strong or weak. If an argument is inconsistent in opinions of strength, the results of persuasion will be inconsistent. In general, a weak argument that is universally viewed as weak will entice unfavorable results if the subject is instructed to and is in an appropriate environment to consider it logically (or when testing the central route of the Elaboration Likelihood Model). In turn, a strong argument under similar circumstances will return favorable results. The test arguments must also be rated for ease of understanding, complexity, and familiarity. To scientifically study either route of the Elaboration Likelihood Model, the arguments themselves must be designed to have consistent results.


Conclusions of the Elaboration Likelihood Model

In addition to these factors, the ELM also makes several unique proposals.

It is suggested that attitudes formed under high elaboration, the central route, are stronger than those formed under low elaboration. This means that this level of persuasion is stable over time and is less susceptible to decay or any type of counter-persuasion. Attitudes formed under low elaboration, the peripheral route, are more likely to cause a short term attitude change. Variables in ELM routes can serve multiple roles in a persuasive setting depending on other contextual factors (examples below). Under high elaboration, a given variable (e.g., source expertise) can either serve as an argument (“If Einstein agrees with the theory of relativity, then this is a strong reason for me to as well”) or as a biasing factor (“if an expert agrees with this position it is probably good, so let me see what else agrees with this conclusion” — at the expense of information that may disagree with it).

Under conditions of low elaboration, a given variable can act as a peripheral cue (e.g., through the use of an “experts are always right” heuristic – note that while this is similar to the case presented above, this is a simple shortcut, and does not require the careful thought as in the Einstein example above). Under conditions of moderate elaboration, a given variable can serve to direct the extent of information processing (“Well, if an expert agrees with this position, I should really listen to what (s)he has to say”). Interestingly, when a variable affects elaboration, this can increase or decrease persuasion, depending on the strength of the arguments presented. If the arguments are strong, enhancing elaboration will enhance persuasion. If the arguments are weak, however, more thought will undermine persuasion.

More recent adaptations of the ELM (e.g.) have added an additional role that variables can serve. They can affect the extent to which a person has confidence in, and thus trusts, their own thoughts in response to a message (self-validation role). Keeping with our source expertise example, a person may feel that “if an expert presented this information, it is probably correct, and thus I can trust that my reactions to it are informative with respect to my attitude”. Note that this role, because of its metacognitive nature, only occurs under conditions that promote high elaboration.


Application of the Elaboration Likelihood Model to HIV Prevention

A study performed in 1999 analyzed the effects of different persuasion techniques when trying to raise awareness of HIV prevention in an adolescent population. 298 eighth grade students were included in the study. Prior to the study, the students were categorized as being “information-oriented,” “normative-oriented,” or “diffuse-oriented” (defensive toward new ideas). The students were randomly assigned to listen to one of four audio messages that ranged from a strong argument, an HIV-infected teenager narrator, to a weak argument, a concerned parent. Upon analyzing their responses to the audio tape and a survey completed after, the “information-oriented” students had a stronger chance at attitude change than the other students. It was concluded that HIV prevention persuasion has much progress to make and that the information must be presented in a way that will reach all types of individuals. In this study, the Elaboration Likelihood Model was being tested for a particular use, and resulted in being effective but underdeveloped for this case.

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