Health Psychology : a Textbook

behaviour and a state of cognitive dissonance to set this up. Totman’s model is illustrated

in Figure 13.2.

Evidence for the role of justification

Research has examined whether a need for justification does in fact relate to symptom

perception. Zimbardo (1969) evaluated the effects of post hoc justification on hunger

and thirst. Subjects were asked not to eat or drink for a length of time, and were divided

into two groups. Group one were offered money if they managed to abstain from eating

and drinking, providing these subjects with good justification for their behaviour. Group

two were simply asked not to eat or drink for a length of time, but were given no reason

or no incentive, and therefore had no justification. Having good justification for their

behaviour, group one were not in a state of dissonance; they were able to justify not

eating and still maintain a sense of being rational and in control. Group two had no

justification for their behaviour and were therefore in a state of high dissonance, as they

were performing a behaviour for very little reason. Therefore in order to resolve this

dissonance it was argued that group two needed to find a justification for their behaviour.

At the end of the period of abstinence all subjects were allowed to eat and drink as much

as they wished. The results showed that group two (those in high dissonance) ate and

drank less when free food was available to them than group one (those in low

dissonance).

The results were interpreted as follows. The subjects in group two, being in a state of

high dissonance, needed to find a justification for their behaviour and justified their

behaviour by believing ‘I didn’t eat because I was not hungry’. They therefore ate and

drank less when food was available. The subjects in group one, being in a state of low

dissonance, had no need to find a justification for their behaviour as they had a good

justification ‘I didn’t eat because I was paid not to’. They therefore ate more when the

Fig. 13-2 Totman’s cognitive dissonance theory of placebo effects

320 HEALTH PSYCHOLOGY