Behaviour Change

PROPAGANDA FOR CHANGE is a project created by the students of Behaviour Change (ps359) and Professor Thomas Hills @thomhills at the Psychology Department of the University of Warwick. This work was supported by funding from Warwick's Institute for Advanced Teaching and Learning.

Thursday, January 23, 2014

Colgate Total

Colgate, one of the most popular brands of toothpaste on the market, successfully persuades consumers to buy this product by using persuasive techniques that Pratkanis (2007) refers to as ‘landscaping’ and ‘source credibility.’

This advert presents a female nurse whose dentist shows her the bacteria in her mouth. After indicating how ‘shocked’ she was at the amount of bacteria, she says that her dentist recommended Colgate Total. After using the product the amount of bacteria appears reduced. This is storytelling, a technique that structures information in order to increase its credibility (Pratkanis, 2007). Evidence has shown that arguments are much more effective when the facts are presented in a causal structure. Slusher & Anderson (1996), for example, were more effective in describing the transmission of AIDS when they presented the facts in a narrative as opposed to presenting them as facts. By setting up the situation in this way, the consumer is likely to be more interested in the product and, as a result, may be more likely to buy it.

The advert uses a communicator of good character to provide a credible source. It achieves this in a number of ways. Firstly, the woman informs us that she is a nurse, a profession that the consumer may associate with honesty and trustworthiness. Research has found that people who are trustworthy are more successful at persuading people on a range of issues compared to untrustworthy sources (Hovland & Weiss, 1951). This means that the communicator is more likely to hold the audience’s attention.

Secondly, they have used a communicator who is physically attractive. Chaiken (1979) found that attractive communicators induced more persuasion than those who were unattractive and Reingen and Kernan (1993) found that targets were more likely to agree to the requests of attractive communicators. We tend to admire attractive people and want to identify with them. Buying something that they use enables us to do this.

Finally, the communicator is used as a source of social proof by way of social modelling. The fact that the woman uses the product means that a consumer is more likely to use it themselves. Bryan and Test (1967) found that when in the presence of a model exhibiting helping behaviour, passers-by were more likely to give to charity. In addition, the communicator is rewarded for this behaviour with the reduced amount of bacteria found in her mouth and a shiny white smile. People are more likely to imitate the actions of models if the model is rewarded for the behaviour (Pratkanis & Aronson, 2001; as cited in Pratkanis, 2007). The consumer therefore, may be more persuaded to buy the product.

The advert ends with an effective message, ‘No. 1 toothpaste brand used by dentists.’ Given that the advert is about improving dental health, a dentist would be seen as an expert source of information due to their specialised knowledge in this area. Research has shown that using an expert to promote a message increases persuasion (Maddux & Rogers, 1980). This closing statement reinforces the adverts message and further persuades the consumer to buy the toothpaste.


Bryan, J. H., & Test, M. A. (1967). Models and helping: Naturalistic studies in aiding behaviour. Journal of Personality and Social Psychology, 6, 400-407.

Chaiken, S. (1979). Communicator physical attractiveness and persuasion. Journal of Personality and Social Psychology, 37, 1387-1397.

Hovland, C. I., & Weiss, W. (1951). The influence of source credibility on communication effectiveness. Public Opinion Quarterly, 15, 635-650.

Maddux, J. E., & Rogers, R. W. (1980). Effects of source expertness, physical attractiveness, and supporting arguments on persuasion: A case of brains over beauty. Journal of Personality and Social Psychology, 39, 235-244.

Pratkanis, A. R. (2007). The Science of Social Influence: Advances and Future Progress. Hove, England: Psychology Press.

Reingen, P. H., & Kernan, J. B. (1993). Social perception and interpersonal influence: Some consequences of the physical attractiveness stereotype in a personal selling setting. Journal of Consumer Psychology, 2, 25-38.

Slusher, M. P., & Anderson, C. A. (1996). Using casual persuasive arguments to change beliefs and teach new information: The mediating role of explanation availability and evaluation bias in the acceptance of knowledge. Journal of Educational Psychology, 88, 110-122.

Alexandra Hampstead

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