The persuasion process is something that occurs throughout our daily lives whether we are aware of it or not. Our attitudes are under constant bombardment from countless forms of advertising, propaganda and other individuals; all with varying degrees of success in persuading us to see things their way. Social psychologists (e. g. Allport, 1935) have long been interested in the study of attitudes and persuasion; due to this there are vast numbers of theories attempting to explain attitude change.

One approach developed by Hovland, Janis and Kelley (1953) has given much food for thought for those interested in attitude change.For a message to be persuasive it must first gain the attention of whoever it is aimed at and must then be posited in a manner comprehensible to the receiver. It must then be mentally rehearsed by the receiver so as to establish a mental link between the arguments contained within the message and the response those persuasive arguments require. Whether the communication actually persuades the receiver depends on a number of other factors, specifically: (1) the source of the communication, (2) the content of the message, (3) the channel through which the message is deployed, and (4) recipient factors.However, there is little agreement as to how these factors actually effect attitude change. The evidence that there are differing cognitive routes to attitude change will be discussed with reference to the elaboration-likelihood model (ELM) and the heuristic-systematic model (HSM).

Both outline competing, but complimentary general frameworks to understand attitude change by proposing two different cognitive routes to attitude change. The idea of cognitive elaboration (i. e. understanding and evaluating a communication) in Petty and Cacioppo's (1986) ELM is essentially derived from Greenwald's (1968) cognitive response model (CRM).The CRM sees people as intelligent information processors but doesn't recognise peoples limitations in attending to information.

In contrast both the ELM and Chaiken's (1980) HSM are dual process models which distinguish between processing involving cognitive elaboration, referred to as 'central route' or 'systematic' processing and the shallower 'peripheral' or 'heuristic' processing. The main premise of the ELM is that people are motivated to hold correct attitudes. Therefore in an ideal world everyone would process information via their central route which involves actively and thoroughly evaluating the message arguments.The person would then be able to draw upon all this information in order to confirm a particular stance. However postulate two of the ELM states that 'although people want to hold correct attitudes, the amount and nature of issue relevant elaboration in which people are willing or able to engage to evaluate a message vary with individual and situational factors' (Petty and Cacioppo, 1986, p.

128). This is similar to Chaiken's assumption that people are "economy minded souls" who require satisfaction with the least amount of effort expended.When time, motivation and ability are limited, cues in the persuasion context may induce change which takes place via the peripheral route in the ELM. This has been called heuristic processing by Chaiken (1980); heuristics are essentially mental shortcuts people use to evaluate an argument. For example source expertise, people may have learned that statements by experts tend to be more valid than those made by non-experts (Eagly and Chaiken, 1984). This decision rule can then be used when a person hears a statement made by an expert to by-pass the 'central' or 'systematic' route.

The main difference between the ELM and HSM is that the conception of heuristic processing is much narrower than the ELM's use of peripheral route persuasion. This has benefits in that it incorporates more variables that may effect peripheral persuasion, however Eagly and Chaiken (1993) argues that as the ELM offers only the most basic explanation as to how peripheral mechanisms operate, it may actually be limited in its use (p. 327). According to Petty and Cacioppo, heuristic processing is one of many strategies (including classical conditioning, identification) that form the peripheral route to persuasion.

They all have in common the fact that the validity of the argument itself is not directly considered by the message recipient, rather only external cues. The two routes could be seen as complimentary as one emphasises argument quality whilst the other focuses on persuasion cues (e. g. source attractiveness) which permit persuasion without affecting argument scrutiny (Petty and Cacioppo, 1986, p. 134).

The differences between the HSM and ELM's shallow processing conceptualisations will be examined later; we shall now consider the evidence supporting separate cognitive routes to attitude change.As mentioned earlier, time, motivation and ability all effect how a message is processed. For central route processing the recipient has to have plenty of time and be sufficiently motivated to comprehend a message that has to be easy enough to understand, yet compelling. The impact of motivation on reception of a message and subsequent acceptance is greatest according to the ELM and HSM, when the message is highly relevant to a person, as they will then be motivated to assess it.

Research suggests that when people expect to be discussing something high in personal relevance, their attitudes become more extreme (Cialdini and Petty, 1981). One study (Cialdini, Levy, Herman, Kozlowski and Petty, 1976) providing evidence for this was conducted on college students opinions on campus issues. A student was instructed they would be discussing something either highly relevant or not, with another student who held opposing views. Whilst waiting, the student was required to list their thoughts on the issue and then complete an attitude assessment scale.It was found that those in the high relevance showed more polarised an anticipatory shift and listed more thoughts in support of their view than those in the low relevance condition.

This was interpreted in terms of those in the high relevance condition thinking harder, and developing their arguments via central route processing; whereas those in the low relevance condition developed weaker arguments via their peripheral route. The participants were later informed that the discussion was cancelled and a further attitude measure was taken.Cialdini et al. ound that only those in the high relevance condition maintained their attitudinal positions.

Therefore central route processing is held to produce more permanent attitude changes than peripheral processing. The above study shows persistent attitude change without persuasive messages being present. Both the ELM and HSM would hold that such change would also occur with persuasive arguments. In testing this, from the ELM perspective, Petty, Cacioppo and Heesacker (1985) had college students listen to persuasive messages varying in relevance, argument quality and source expertise.They found that all students exposed to strong arguments from an expert source had more favourable attitudes than those exposed to weaker arguments from a poor source.

In a follow-up attitude test two weeks later only those in the high relevance condition still held their positive attitudes. Therefore under high relevance conditions, the attitude change was primarily determined by the strength of the arguments as opposed to the low relevance condition whereabouts attitudes were determined by source expertise and therefore had no lasting effect.These results are supported by previous studies (Chaiken, 1980; Petty and Cacioppo, 1979; Petty, Cacioppo ; Goldman, 1981). Other studies have found variables such as message length, message quantity and audience involvement also influence attitude change when personal relevance is low (Maheswaran ; Chaiken, 1991; Petty and Cacioppo, 1984; Wood et al. 1985).

The impact of ability has also been found to be an important factor in determining whether the shallow or deeper processing route is to be taken.Both the ELM and HSM would accept that the more intelligent the person the more likely they would be to understand and process complex arguments in respect to an attitudinal position (e. g. Eagly and Warren, 1976).

The manipulation of distraction has been used to control participants ability to process information ever since Festinger and Maccoby (1964) found that distracting participants from a persuasive message led to increased attitude change.Petty, Wells and Brock (1976) conducted two experiments where distraction was manipulated by having participants write down what visual images they could see whilst simultaneously listening to either a strong persuasive message or a weak one. Distraction was risen further by increasing the speed at which the visual images were shown. They found that as distraction increased persuasion was enhanced in the weak argument condition; whereas distraction reduced persuasion in the strong argument condition.Further support was provided when afterwards participants had to list their thoughts after the experiment: while distracted participants were inhibited in their ability to produce counterarguments against the weak arguments and also in their ability to list supportive thoughts for the strong arguments. Many replications and further studies have also found that lowering the ability of participants leads to the use of peripheral or heuristic cues rather than the more complex and demanding central route to persuasion (for reviews, see Petty and Cacioppo, 1981).

In both cases the degree of persistence in attitude change depends upon the likelihood of elaboration which mostly depended upon the messages personal relevance. However, Petty and Cacioppo (1980, cited in Eagly ; Chaiken, 1993) also found that source attractiveness affected the degree of persuasion of participants regardless of personal relevance. This leads to the question of whether peripheral or heuristic cues may have an effect on persuasion in all conditions, relevant or not.Whether the two routes to persuasion are mutually exclusive or not isn't specified by Petty and Cacioppo, though this lack of information implies they are. To discard peripheral cues where personal relevance, ability and motivation is high would be implausible, as Eagly and Chaiken (1993) points out: 'do people knowingly ignore [or resist] peripheral cues such as source attractiveness [..

. ] when the elaboration likelihood is high? ' (p. 322). The HSM accepts that the two routes to persuasion can be both independent and interdependent having something like an additive effect on judgement.When elaboration likelihood is low a person may use only peripheral cues in absence of a strong argument; when high a person may take in all arguments and cues available thus strengthening the central route to persuasion.

In the latter case the heuristic cues may not have any noticeable effect if taken out but it may still have a small additive effect. Argument quality has been acknowledged by both HSM and ELM as being a prime determinant of whether the deeper central or systematic route is taken or rather the shallower peripheral or heuristic route.However, what isn't made clear, certainly by the ELM, is what exactly makes an argument persuasive; for this Chaiken and others turn to the expectancy value approach (Fishbein, 1963). What is clear is that the elaboration likelihood and heuristic-systematic models are both very similar in their usage of two different cognitive routes to attitude change; though the former is much more a general framework from which one can investigate persuasion and the latter an explanatory device from which to explain persuasion.The two models are essentially complimentary in that when put together they encompass most of the research into attitudes under one empirical and theoretical umbrella. In conclusion, there is little doubt that their are two, if not more, cognitive routes to attitude persuasion.

An attitude is generally accepted as referring to a 'general and enduring positive or negative feeling about some person, object or issue' (Petty and Cacioppo, 1981, p. 7); therefore it is necessary for there to be at least two cognitive routes so as to account for the results presented above.Ideally all information would be processed fully with all possible arguments and heuristic cues being taken into consideration. However, in daily life we cannot pay full attention to every message we hear, no matter how relevant to us it is; therefore we have to have some form of peripheral processing to save time and prevent our brains going into overload.

Time, motivation and ability will all effect how a message is processed; this complicated process ensures that much communication is dealt with peripherally, which as has been shown, leads only to short term attitude change.In combination, the ELM and HSM provide a sound framework from which we can further understand how attitudes can be derived via different cognitive routes. Further research should perhaps use these models to discover to what extent heuristic cues affect central or systematic processing; whether their may be a middle ground in which both play an equal role in determining attitude change (for reviews, see Eagly and Chaiken, 1993).