Behaviour Change

PROPAGANDA FOR CHANGE is a project created by the students of Behaviour Change (ps359) and Professor Thomas Hills 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, March 3, 2016

Is sugar really that sweet?

Authority is well known to act as a persuasive technique. This ad uses a photo of a doctor giving advice to the reader, as well as phrases such as 'Doctors say...' to give the impression of an informed, authoritative viewpoint. The classic Milgram (1963) study shows the extreme effect that an authority figure can have on an individual's behaviour. In the study, participants complied with requests given by an 'experimenter' to increase the voltage of a shock being given to a confederate, even to lethal levels. Participants associated the authority figure with expertise and thus repressed their own concerns. The use of an attractive doctor persuades the reader in two ways: the appearance cues indicate credibility, whilst attractiveness increases likeability. A high level of credibility and attractiveness have both been shown to positively increase persuasion (Chaiken, 1979). Moreover, using an image of a highly credible source that relates to the discussed topic increases the credibility of the message and thus makes the reader more receptive to it (Nguyen & Masthoff, 2007).

The ad also takes a negative spin on the issues at hand, displaying the negative consequences of high sugar intake, rather than the benefits of cutting down. In Meyerowitz and Chaiken's (1987) study, they found that a pamphlet utilising loss-framed language was far more effective at changing attitudes and prompting action for breast screen examinations, with a belief that their current behaviour could be changed increasing the likelihood of behaviour change. Perhaps interestingly, current research has shown that message framing can be enhanced by colour cues. Gerend and Sias (2009) found that loss-framed messages were more effective when presented in the colour red than a neutral colour. The use of the colour red as a peripheral threat cue in this ad helps to emphasise the negatively framed message.

The use of the NHS as a source of information also seems appropriate for this kind of campaign.As a reputable and well established organisation used by the majority of people, it is likely to present itself in the reader's in-group, and so its message is much more likely to be seen to be credible. Hovland and Weiss (1951) conducted a study in which information presented to participants was believed much more when the source was deemed to be credible than when not.

Finally, the ad uses social proof to persuade the reader to cut down their sugar intake using an image of a large group of various ages declaring 'We're cutting down on sugar, why aren't you?'. Social proof suggests that we decide what is right and appropriate by the actions of those around us. The use of a group with a variety of different people means that the reader is likely to relate to at least some members of the group. Cialdini (2001) uses social proof as one of his 6 principles of persuasion, noting that people are more likely to perform an action if they can relate to the people that have performed the same actions. This has been shown in a number of studies, including people donating more to a charity campaign if they knew the people on the donor list.


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

Cialdini, R. B. (2001). Harnessing the power of persuasion. Harvard Business Review, 79, 72-81.

Gerend, M. A., & Sias, T. (2009). Message framing and color priming: How subtle threat cues affect persuasion. Journal of Experimental Social Psychology, 45, 999-1002.

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

Milgram, S. (1963). Behavioural study of obedience. Journal of Abnormal and Social Psychology, 67, 371.

Meyerowitz, B. E., & Chaiken, S. (1987). The effect of message framing on breast self-examination attitudes, intentions and behaviour. Journal of Personality and Social Psychology, 52, 500.

Nguyen, H., & Mastiff, J. (2007). Is it me or is it what I say? Source image and persuasion. In Proceedings of the Persuasive Conference (Stanford, USA). Springer-Verlag, Berlin.

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