Running head: The ELM: A Review
The Elaboration Likelihood Model: A Review
Anthony B. Shelton
Radford University
The ELM: A REVIEW
ABSTRACT
This paper is a review of the Elaboration Likelihood Model of persuasion (ELM). We discuss
ELM and its main components. First, the dual-process nature of ELM consisting of the central
and peripheral routes is explained. Next, some of the main postulates from the original article are
discussed among these are the variables of ELM, motivation and ability, as well as the role of
argument quality and peripheral cues. Some components of motivation and ability are addressed.
A summary of ELM is presented. Some expansions of ELM are addressed such as further
defining argument quality, testing other variables, and expanding practical understanding of
peripheral cues. Some criticisms are addressed, specifically several from the Michigan State
critics. Applications of ELM are explored in a few contexts. The lack of research into ELM
applications in social media are addressed, as well as a general lack of theoretical development
into the new social media contexts.
The ELM: A REVIEW
The Elaboration Likelihood Model of persuasion (ELM) is a staple of any discussion
about major communication theories. First truly proposed in 1986 by Richard Petty and John
Cacioppo, ELM looks at persuasion as a dual-process. It attempts to place our understanding of
persuasion into a model with practical implications. Being close to 30 years old, this theory has
been critiqued and reviewed and expanded many times both by its creators and others. This is
just one more vantage point for ELM.
The focus of this paper is to review some of the major literature of ELM. We will discuss
the original work of Petty & Cacioppo by laying out the processes of the model and the factors
that influence the routes taken. We will also look at some responses to criticism as well as
address some applications of the theory. Lastly, we will discuss how the utility of the theory has
been considered in a social media context and what the future might hold in that regard.
As early as 1981, Petty & Cacioppo proposed that through all of the body of persuasive
theories to date, there was an underlying theme. No matter what the research was done on, they
believed that the research was basically highlighting the existence of one of two different
cognitive routes that people use to make decisions when confronted with a persuasive attempt.
They defined these two routes as the central and peripheral routes (Petty & Cacioppo, 1981).
These two routes define the ways in which people cognitively process a persuasive message and
are very similar to Chaiken’s (1980) systematic/heuristic information processing model.
They argued that one body of work highlighted what they called, a central route to
persuasion. This route was a route in which “a person's diligent consideration of information that
[they] feel is central to the true merits of a particular attitudinal position (Petty, Cacioppo &
The ELM: A REVIEW
Schumann, 1984).” They also believed that any decisions that were made using this route were
more lasting or enduring than other types of decisions.
When those things did not take place, they pointed to a second body of work that
suggested what they deemed, the peripheral route. In contrast to the central route, this route does
not involve a diligent consideration or pondering of the arguments presented. Instead, they
believe that those who took this route would merely use simple cues from either the way or
method in which an argument is presented or even from its context (Petty & Cacioppo, 1984).
Again, in contrast to the central route, persuasion achieved through the peripheral route was
believed to be less enduring or permanent.
Their book on persuasion and advertising, as well as the articles that build on the ideas of
involvement and argument quality were the beginnings to what would eventually become ELM.
ELM is a dual-process model that uses both of the aforementioned routes as its processes. In
1986, Petty & Cacioppo published the original article that is the foundation for ELM. In this
article they build on two processes, describing them in a bit more detail as well as some factors
that affect which route is used in a given situation. The theory is divided into seven postulates,
five of which we will address from this particular article.
The first postulate is a major theoretical assumption. Petty & Cacioppo (1986a) assume
that people want to hold correct attitudes. We believe that incorrect attitudes will have negative
consequences in our lives. The implication of this assumption being that when we observe
people we should expect to see them engage in behavior that aides in determining whether or not
their attitudes are correct.
The ELM: A REVIEW
In their second postulate states that the amount and nature of elaboration in which people
are willing or able to engage varies. This is the first mention of elaboration. Elaboration is
defined in their research as, “the extent to which a person thinks about the issue relevant
arguments contained in a message.” They believe when conditions encourage people to a high
motivation or ability then their likelihood of elaboration will be high. They also believe that
objective or biased forms of elaboration can take place, which they discuss in a different
postulate. Along with this, they assume that people are not motivated enough or even actually
able to carefully elaborate upon every message they encounter. As a result, elaboration in these
situations is said to be low. At this point, they establish a continuum of elaboration. Essentially,
on one end you have likelihood of high elaboration, driven by motivation and ability (the central
route) or when the roles of those factors are diminished the likelihood of elaboration is low (the
peripheral route). This also allows us to clear up a popular misconception that people only take
either one route or the other when, in reality, Petty & Cacioppo have created a continuum and
one’s elaboration may fall anywhere in between the two routes (Petty & Cacioppo, 1981),
causing them to overlap when a medium amount of elaboration is likely.
In their third postulate they state that there are variables that affect attitude change by
either serving as persuasive arguments, peripheral cues, or affecting the extent of elaboration (or
any combination thereof). One of the most important topics they discuss is argument quality. At
the time this was a topic that was not very well studied. Petty & Cacioppo believed that it was
very important when crafting persuasive messages and agreed with Fishbein & Ajzen (1981)
when they asserted that it was “probably the most serious problem in persuasion research.” If
elaboration likelihood is high then strong arguments will have a greater chance of achieving
persuasion, while if the likelihood is low, then weaker arguments would be more effective. Since
The ELM: A REVIEW
elaboration falls onto a continuum, their suggestion is that varying the quality of arguments will
increase the effectiveness of influencing attitudes. Along with this they discuss peripheral cues
specifically that a manipulation of messages can serve as peripheral cues, which are more
effective when elaboration is expected to be low. In this section they also discuss objective vs.
biased processing. When objective processing takes places, subjects see the strengths of cogent
arguments and the flaws in specious ones. When biased processing takes place, subjects will
generate a particular thought or inhibit one (Petty & Cacioppo, 1986a).
Next, they postulate that variables that affect motivation or ability in an objective manner
will enhance or reduce argument scrutiny. Essentially, when certain variables change people will
elaborate more or less. The variables discussed fall under two categories, motivation (egoinvolvement/personal relevance, responsibility, and need for cognition) or ability (distractions
and repetition). With motivational variables like the ones mentioned, the greater they variable is
(more involvement, more responsibility, more need for cognition) then the more motivated
subjects will be to process a message which results in a higher elaboration likelihood. In these
situations you want to focus on stronger arguments. Ability variables are not as cut and dry.
Distractions will disrupt the thoughts of subjects and lower the ability of subjects to process a
message. When they occur, more simple arguments and more peripheral cues are best. Repetition
on the other hand increases a subject’s ability to process a message and so the reverse is true but
only up to a point. Cacioppo & Petty (1979) establish a two-stage model wherein after the
implications of an argument repetition will begin to have the opposite effect due to tedium and
reactance. Along with these things, you can actually design your message to use these variables.
Aspects of your message can aid in increasing perceived involvement or responsibility which
The ELM: A REVIEW
allows you to control elaboration likelihood, as well as using repetition when you feel you have
strong arguments or distractions to guide elaboration as well.
Figure 1 (Adapted from, Petty & Cacioppo, 1986b)
To wrap up the basis for what we understand as ELM, we will look at postulate five,
which is fairly simple and straightforward, “as motivation and/or ability to process arguments is
decreased peripheral cues become relatively more important determinants of persuasion (Petty &
Cacioppo, 1986a).” The reverse is also true. These ideas were discussed in terms of source cues
(a prime example was used from the 1980 article by Chaiken; see Experiment 2) and message
cues (example: Petty & Cacioppo, 1984). These ideas help us to wrap up, rather nicely, an
The ELM: A REVIEW
overview of ELM. In the chart from Figure 1 above, a visual diagram of ELM is presented to
help streamline and conceptualize the ideas.
Overall, we have created a good general look at ELM. To summarize, it is a dual-process
model utilizing two routes of processing, central and peripheral. The central route is taken when
more thoughtful consideration (or high elaboration) takes place. The peripheral route is taken
when simple cues are relied on instead (low elaboration). These routes are influenced by several
variables categorized under motivation (such as ego-involvement or need for cognition) and
ability (such as distractions or repetition). The higher motivation and ability, the higher
elaboration likelihood and the stronger argument quality should be. The lower motivation and
ability, the lower elaboration likelihood and the more you should rely on peripheral cues. From
here we can step back and look at some of the developments in ELM over the years, as well as
some responses to criticisms of the theory, and a few applications.
One of the earlier expansions of ELM was by Areni & Lutz (1988). Their study took a
look at argument quality and essentially raised some questions about what that actually meant.
The way the original theory was proposed, it seemed like any argument that could elicit a
positive response was strong and any that exhibited a negative response was weak. They were
able to help differentiate by establishing two variables of argument quality, strength and valence.
Argument strength is based on the probability that the argument is associated with some specific
consequence, while argument valence was defined as how the subject evaluates that
consequence. This view helped give a little more clarity to how arguments should be constructed
when using ELM to create persuasive messages.
The ELM: A REVIEW
There are several other variables that are looked at by studies as well that help to expand
the concepts of ELM. There are many but a few are worth noting. In one article it was concluded
that mood plays an important role in elaboration (Worth & Mackie, 1987). This study found that
when subjects were in a more positive mood, that they were less likely to engage in high
elaboration and that their recall of the arguments was low, instead focusing on the presence of
peripheral cues. Conversely, when the subjects were in a more negative mood they would engage
in higher levels of elaboration and recall more about the arguments presented and less on cues.
Another study attempted to undermine the notion that the number of sources was a
simply peripheral cue (such as the more endorsers for a product, the more likely people will buy
it). They found that for strong arguments, increasing the number of sources tended to increase
elaboration, while if the argument was weak, less elaboration was more likely. However, they
also found that if arguments were weak, increasing sources actually increased negative responses
as well (Moore & Reardon, 1987).
And yet another study found that knowledge was an important factor. Essentially, the
more working knowledge of a subject one had, the more likely they would focus on the argument
quality; the less knowledge, the more they focused on simple cues (Wood, Rhodes & Biek,
1995). This study also found that the higher the affect tied to their knowledge, the more they
would scrutinize the argument.
One of the most useful expansions of ELM is Cialdini’s (2001) weapons of influence.
These “weapons,” as they are called, are heuristic (peripheral) tactics that help to expand our
understanding of how to utilize the peripheral route of persuasion. These weapons include:
reciprocation (people are more open to persuasion if they have received something with no
The ELM: A REVIEW
expectation of return, they feel the need to reciprocate), commitment and consistency (assumes
that people like to hold consistent views and states that people are more likely to be persuaded if
they make commitments as a part of a persuasive attempt), social proof (people desire approval
and are more likely to do what others have done or are doing), liking (people are more easily
persuaded by those they find attractive, smart or like themselves), authority (people are more
likely to be persuaded by someone they perceive as an authority figure), and scarcity (people are
more likely to be persuaded when they believe there are only a limited number of options
available to them). The ability to understand and harness these heuristics improves upon the
utility of ELM.
These are just a few of the many expansions of the theory. ELM is one of the most
widely panned and studied theories in communications and certainly in persuasion. Petty himself
recognized the praise it had received as well as the large number of studies it has guided (Petty &
Wegener, 1999). These are just a few that are particularly useful in crafting persuasive messages.
Along with expansions, there are some criticisms of the theory as well.
In their 1993 article, Petty, Wegener, Fabrigar, Priester, & Cacioppo give a whole host of
responses to various criticisms. The first criticisms addressed are from Hamilton, Hunter, &
Boster (1993). The criticisms were essentially that ELM did not constitute advancement in
understanding, that certain components of the theory were wrong and that there were problems
with peripheral attitude change assumptions. The first criticism is easily dispelled as the value of
ELM is now widely accepted. The biggest concern was that there was no difference between
ELMs routes of persuasion and Chaiken’s (1980) model of heuristic vs. systematic processing.
Petty et al. argue that the purposes and applications for these routes are different and that ELM’s
dual-processes constitute a mentionable advancement in persuasion research. The other
The ELM: A REVIEW
criticisms, they argue are based in the incorrect assumption that ELM is making absolute claims
rather than relative ones. For example, rather than predicting a boomerang effect in the presence
of negative thoughts, ELM more appropriately states that resistance and boomerang become
more likely as negative thoughts increase.
Next they address Mongeau & Stiff’s (1993) claims that there is a lack of specificity in
LEM and that a covariance model might be a better persuasive model. Petty et al (1993)
responds that they are lacking in an appreciation for the basic assumptions of the theory and that
there is plenty of specificity in ELM. However, it is interesting here to note that they actually
agree somewhat with their critics. While Petty et al does not concede that a covariance structure
model would replace ELM, they do believe that the use of the model will enhance and expand
understanding of ELM. Also, in response to a demand for central and peripheral roles,
emphasized that the variables will serve in different roles based on varying conditions. They
conclude by reemphasizing that ELM has drawn and built upon preexisting understandings of
persuasion and that the contributions of ELM has helped spawn more research in the field and
has been supported overall by research based upon it.
Again these are only a few criticisms that have been addressed. As mentioned in the
rebuttals provided by Petty et al (1993), they are rooted in misperceptions or misunderstandings
about ELM itself. Another important step in reviewing ELM is to look at some of the
applications for the theory. There are plenty to draw from but we will only look at two.
One excellent application of ELM is increasing the effectiveness of communication to
consumers. One way to do this is to look at whether or not there will be a good fit between the
elaboration of your audience and the target elaboration for effectiveness (Rucker & Petty, 2006).
The ELM: A REVIEW
If your audience will not be engaging in enough elaboration for your message to be effective,
then why waste the effort? Another helpful application suggested by Rucker & Petty is to
measure the attitudes, attitude certainty and thoughts of your audience. This can help you
understand how each of your arguments can be crafted based on the attitudes that are held and
their certainty of them and you could better predict elaboration.
Another excellent application of ELM would be in advertising research. ELM is very
widely studied and used in the advertising discipline for this reason. There is reason to believe
that rather than certain factors affecting the central and peripheral processes it is an
amalgamation of factors that add up to how likely elaboration is (Lien, 2001). Lien also confirms
that both central and peripheral processing can take place simultaneously. Along with this, there
are no cues that purely peripheral or central but they can serve different functions based on the
context. In advertising, some of the variables that could be used are: the content of ad claims
(content can either be designed for the central or peripheral routes), comparative advertising
claims (again, these can be designed to appeal to those who will engage in higher elaboration or
for lower), pictures in print ads and camera angles (certain images and presentations of those
images can encourage or discourage elaboration). Along with these cues Lien also discusses the
roles of positive affect, source expertise, processing goals, and attitude toward the ad, all of
which again builds upon the idea that the central and peripheral routes are not exclusive but can,
and do, occur simultaneously.
All of the things we discussed build a really nice idea of what ELM is and how it can be
used to craft persuasive messages. By this point we should have a pretty solid understanding of it
as a theory, with some expansions, criticisms, and applications.
The ELM: A REVIEW
Unfortunately, there is not much research on how ELM can be applied to social media.
Sharma, Singh & Pahwa (2012) noted the blurring of mass media into social media and the
importance of this new technology. Though social media is a young medium, it is surprising the
lack of theoretical research into. In fact, there is essentially none. There are a few studies into
online usage of ELM, however.
Karson & Korgaonkar (2001) seemed to draw from their study that ELM might not be
practically useful in online advertising. However, they noted that more research is required and
most essentially that future studies should focus on if there is a single element of Internet
advertising that is unique (such as interactivity) or is it more of a Gestalt principle, the sum of
many small differences? They acknowledge the difficulties in testing between media, settings,
and people but affirm the importance of it for our understanding.
Along aspect where ELM seems like it could come in handy is in the online shopping
world. Chen and Lee (2008) looked at just this. They discovered that consumers with high levels
of agreeableness and conscientiousness would be more favorable toward websites that focus on
persuasion by strong argument quality. On the other hand, consumers with high levels of
emotional stability, openness, and extraversion were more open to websites favoring peripheral
cues. These findings are significant in that the integration of personality traits along with ELM
have been largely untested in this way, which is a cause for optimism. They proposed that the
consumer’s beliefs about a website designed with the central route in mind will have a
significant influence on their perceived utilitarian value of the product while a site more geared
toward peripheral cues may lead to influence on the perceived hedonic value of the products.
These views of the products and beliefs about the website can generate more trust in the website,
The ELM: A REVIEW
as well as credibility for the website, especially in respects to having a long term relationship
with the consumer.
One article studied attempts to expand upon ELM by including Vehicle Exposure (the
medium used for the ad), Opportunity to Process (involuntary exposure, such as a banner ad),
Level of Product and Personal Involvement (motivation to process), and Voluntary Exposure
(such as clicking an ad) as variables affection elaboration (Cho, 1999). Based on this Modified
Elaboration Likelihood Model (MELM), Cho proposed several hypotheses: People with high
involvement are more likely to click on ads, people with low involvement are more likely to
click on ads that are larger or more visually appealing, a higher relation between the product and
website where the ad was places will generate in more clicking of the ad, if people are more
favorable toward the vehicle they are more likely to click the ads if the products advertised are
relevant, and people with a more favorable view of advertising will be more likely to click on
ads. Each of these hypotheses was able to be backed up in the study. These results are
encouraging and Cho believes that MELM will be extremely useful in looking at how people are
persuaded using advertisements on the internet. This article is still interesting 13 years later,
which is basically an eon when speaking about technology. It will be exciting to see future
studies of the tenets of this “modified” ELM, such as how interactivity of online persuasive
messages could affect elaboration and persuasion.
There are a lot of interesting things to discuss about new media and technology like the
Internet and social media. Much like the printing press put more information in the hands of the
masses, the internet has empowered individuals and enabled them to have access to more
information than ever before at almost any time they desire. Likewise, social media seems to be
as fundamentally different from some mass media as mass media was from traditional media.
The ELM: A REVIEW
Though it may take some time to gain traction the future may hold much promise for theories
about how we interact in a virtual world and perhaps even through social media. Like in all
disciplines, ELM will remain an important theory to expand and adapt into these contexts, as the
ability to craft effective and persuasive messages will always be useful.
The discussion presented displays how large and encompassing ELM is. This discussion
in particular has only been able to touch lightly upon ELM as a theory. Research into persuasion
and the central and peripheral routes and especially into the variables of ELM is seemingly never
ending. There will always be more developments and we grow to understand persuasion better
and as technology changes the way we think and interact. As the theory develops more criticism
will be levied and require more defense and scrutiny from communications researchers. As
always, the bottom line will continue to drive demand for applications. Academia will lead the
way but as these concepts prove to be more and more useful to profit-based organizations there
will always be demand for newer and more effective ways to use ELM. Petty & Cacioppo’s
Elaboration Likelihood Model has more than stood the test of time and looks to stand for some
time to come.
The ELM: A REVIEW
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