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.

Wednesday, March 5, 2014

Brannon & Brock: the workings of the Scarcity tactic

Blog 3. Scarcity Claims Elicit Extreme Responding to Persuasive Messages: Role of Cognitive Elaboration (Brannon and Brock, 2001)

Brannon and Brock’s (2001) paper aims to discover whether the compliance tactic of scarcity works due to heuristic-reduced thinking, or elaborative-increased thinking. Cialdini’s (2007) scarcity principle maintains that something is more attractive when its’ availability is limited, or when one stands to lose the opportunity to acquire them. Cialdini further claims that this compliance tactic works because it is a heuristic- an automatic response, applying a ‘rule of thumb’ such as ‘what is rare is good’ (Cialdini, 1993). This paper examines whether scarcity does operate in this way, as opposed to relying on elaborative processing- that extreme reactions to scarcity tactics are due to “enhanced elaboration rather than to automatic inferring” (Ditto and Jemmott, 1989). For example, it may be that scarcity encourages further evaluative thought, considering the advantages and disadvantages of that being advocated, subsequently resulting in a more extreme reaction. Equally, it seems that this account would allow for negative changes in response to a scarcity cue, which the heuristic account cannot allow for due to the rule of thumb merely explaining the positive: “what is rare is good”.
In order to evaluate this, Brannon and Brock carried out 2 experiments. The first attempted to detect whether differential evaluative processing increased for positive and negative messages regarding a personal character trait, due to the subjects' perceived prevalence of that attribute. Subjects were 131 American undergraduates who had to fill in a questionnaire in order to determine whether they were ‘picture-minded’. This was rigged so that all people achieved the highest score.They were then told either that this trait was very rare or very common, and were read a positive or negative message regarding this ability. 
The results demonstrated that the subjects’ thoughts and feeling were more extreme (either positively or negatively corresponding to the message valience), in the scarcity condition. In other words, more negative thoughts were generated with the negative message + scarcity condition, and vice versa in the positive condition. The number of thoughts that were consistent with the messages’ valence was referred to as the ‘message-consistent evaluative thinking’, and there was a direct link between this and scarcity. This demonstrates that the impact of scarcity on attitude extremity was mediated by an increase in evaluative thinking. Thus, experiment 1 demonstrated that an elaborative, rather than heuristic, response to scarcity information took place.


Experiment 2 also replicated Experiment 1 in establishing the extremitizing effect of scarcity information due to evaluative thinking. In this, a comparison between induced cognitive load and no-load was used to determine whether this had an effect on attitude extremity due to scarcity. It was found that reduced thinking (higher cognitive load) prevented extreme reactions to this message- resulting in less message-consistent thinking. The finding that unimpaired thinking resources enabled extreme attitudes under scarcity demonstrates evidence against heuristic-reduced thinking because, if so, one would be able to use this even in high cognitive load circumstances and as such elicit extreme attitudes- which is not what is seen to happen. Cognitive load reduces overall thinking as well as eliminating differences in thinking which facilitated attitude changes- in other words, under cognitive load, manipulated scarcity was not correlated with attitude extremity.


As such, it demonstrates that scarcity does not induce heuristic-reduced thinking, and instead the extreme reactions induced by the scarcity tactic are due to elaborated cognitive thinking. Subsequently, the take-home message for compliance  professionals is in order to successfully use the scarcity tactic, avoid inducing cognitive load on the person, or anything which make cause a reduction in thinking abilities.

Katie Haseler-Young




Brannon, L. A., & Brock, T. C. (January 01, 2001). Scarcity Claims Elicit Extreme Responding to Persuasive Messages: Role of Cognitive Elaboration. Personality and Social Psychology Bulletin, 27, 3, 365-375.

Cialdini, R. B. (2007). Influence: The psychology of persuasion. S.l.: Collins.

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