The Role Of Thought Confidence In Persuasion

This research stems from one of the dominant models of persuasion, the Elaboration Likelihood Model (ELM) (Petty & Cacioppo, 1986), which argued that your mind can take one of two routes when encountering a persuasive message. The route you take depends on how motivated and able you are to process the message. If your motivation and ability are low because, for example, you are uninterested or distracted, then you will take the peripheral route. This usually results in only a temporary attitude change because your attitude will be affected by heuristic cues, or mental shortcuts, that are often associated with the source delivering the message.

However, if your motivation and ability are high because, for example, the topic is very relevant to you, then you will take the central route. This means that your attitude will be affected by the content of the message, and typically leads to permanent attitude change. Under these conditions, the source can influence attitude change through various psychological processes, which include self-validation. The confidence we have in our thoughts about a message can be manipulated by three source factors: credibility, similarity, and power.

Credibility comprises trustworthiness and expertise, and often refers to the believability of the source. Tormala, Briñol & Petty (2006) discovered that a high credibility source increased a message’s perceived validity. They claimed that this made participants feel more confident in their thoughts about the message, which then enhanced its persuasiveness.

But what is more interesting is the finding that high credibility sources were only more persuasive than low credibility sources when they provided a strong argument. As part of the same study, participants read a message promoting a new aspirin product, which contained strong or weak arguments, and wrote their thoughts down about the message. Half of each group were told that the message was taken from a pamphlet produced by a federal agency that conducts research on medical products (high credibility), while the other half were told it was from a class report written by a student (low credibility).  

All participants then had to report the confidence they had in their original thoughts. They found that ‘if a message is weak and produces primarily unfavourable thoughts, high source credibility can actually backfire and be less persuasive than low source credibility’ (Tormala, Briñol & Petty, 2006). It was argued that this was because a high credibility source increased confidence in the negative thoughts generated about the weak argument.

Social attractiveness – in particular, similarity – is another integral dimension of persuasion, because it promotes cognitive responses. Unlike credibility, the individual becomes the source of validation, rather than the source of the message itself.

Petty et al. (2002) manipulated the extent to which participants perceived their thoughts as similar to other participants’. Undergraduates from Ohio State University read a strong or weak message in favour of comprehensive exams and then listed their thoughts about the message. Half of the participants in each group were told that their thoughts had been rejected for future reference because they were only 8% similar to other students (relatively low). The other half were told that their thoughts had been accepted for future research because they were 87% similar to other students (relatively high).

All participants were then asked to think back and rate their confidence in their original thoughts. Results revealed that attitude change was greatest for participants who were told that their thoughts were similar to other participants’. They argued that this was because those who knew that others held similar thoughts — whether positive or negative — had more confidence in those thoughts. Participants then relied on them more during attitude formation compared with those who perceived their thoughts as dissimilar to others.

The last dimension is power, and, much like similarity, it is about the individual as a source of validation and how their perceived power is manipulated. Power is vital in persuasion because it plays a pivotal role in human relationships, and studies have shown that high power sources are perceived as more persuasive than less powerful sources.

Taking this one step further, Briñol et al. (2007) suggested that ‘power leads to more confidence in whatever actions one is considering’. Participants were required to list thoughts that were either in favour of or against a new vaccination policy. Half of the subjects were asked to recall an incident when they had power over someone else and conversely the other half were asked to recall an incident when someone else had power over them. Finally, they were told to rate their confidence in their initial thoughts. The attitudes of high-powered individuals showed more differences between pro-arguments and counter-arguments than the low-powered individuals because, once again, they felt more confident relying on their recently generated thoughts.

Interestingly, however, when the power manipulation took place before people read the message, high-powered individuals showed fewer attitudinal differences because they were so confident that they did not engage with the message. On the other hand, the low-powered individuals became motivated to focus and displayed greater attitude changes.

The ELM has provided a more sophisticated understanding of how attitude change works. It has helped develop health promotion campaigns and interventions pertaining to issues such as dental flossing (Updegraff, Sherman, Luyster & Mann, 2007) and eating disorders (Withers, Twigg & Wertheim, 2002). It has also been applied to the domain of social change, for example, with the impact of entertainment-education messages (Slater & Rouner, 2002) and workplace aggression (Douglas et al., 2008) as well as commerce, including the role of personality traits and perceived values in online shopping (Chen & Lee, 2008) and trust in mobile banking (Zhou, 2012).

More specifically, Briñol & Petty (2009) claimed that ‘research conducted on self-validation has examined the effect of thought confidence with regard to a variety of attitude objects and measures, increasing the potential applicability of these results in the real world’. Indeed, there is evidence that its applicability is far-reaching. Covarrubias & Fryberg (2015) used the self-validation hypothesis to explain why Native American students’ sense of school belonging increased with the number of role models they identified. Blankeship, Nesbit & Murray (2013) applied the research to understand the relationship between aggression and driving, where those who displayed anger were more confident in their thoughts during a provoking situation. Finally, Santos and Rivera (2015) found that people were more likely to punish an anti-social target when they were exposed to the idea of ethics and legality, because it validated their negative thoughts.

The art of persuasion has been a point of both interest and mystery for centuries due to its powerful ability to change people’s minds. The discovery that thought confidence affects attitude change highlights the complexity of the process because it is no longer simply a question of getting people to think positively about a message, but how best to increase the confidence in their thoughts. Its application to the world of persuasion is still in its infancy, but the self-validation hypothesis undoubtedly sheds light on the mechanics of attitude change and offers a promising solution to developing effective persuasive messages.