Combining source trustworthiness with message credibility. Are you being persuaded

The purpose of this thesis is to determine what the effects are of advertisements that combine an expert source with messages that differ in argument quality. The majority of prior research focusses on addressing different sources but rarely on comparable sources. The two messages contained either strong or weak arguments and strove to persuade readers to purchase a PV-installation. Use has been made of a 2X2 experimental research design. The two expert sources were an engineer and a salesperson. The two sources were combined with a text containing either strong or weak arguments. Prior to gathering the final data a pretest was conducted in order to determine what arguments were perceived as strong or weak and whether or not the two expert sources were indeed seen as an engineer or a salesperson. Furthermore a model was developed and tested. Four different advertisement combinations were developed. After being exposed to the advertisement participants were asked to fill out a questionnaire that measured six constructs by means of existing scales. A net response of n=151 was managed which was equally distributed for all four advertisements combinations. A Factor analysis determined that the items properly measured the six constructs. A two-way ANOVA analysis measured no main effects but showed that there was an interaction effect for a combination of engineer and strong arguments on the integrity of the engineer and the credibility of the message. The model was tested too and a correlation coefficients test showed that there is a positive relation between source trustworthiness and message credibility. A linear regression analysis showed that the three constructs that account for trustworthiness have a positive influence on the participants’ attitude towards the product. Also a linear regression analysis shows that credibility has a positive influence on the participants’ attitude towards the product and that a positive attitude will lead to a higher purchase intention. When an engineer uses strong arguments he is perceived to have more integrity than when he uses weak arguments. This applies to message credibility too. Whether or not a salesperson uses strong or weak arguments had no influence on the ability, benevolence or integrity of that salesperson. A similar outcome applies to message credibility. Also there was no significant interaction effect for source type and argument quality on the attitude and the purchase intention of the respondents. As for the model testing, when a source is perceived as trustworthy the message will automatically be perceived as more credible. Both the source trustworthiness as well as the message credibility significantly influenced the attitude towards the product. When a message is perceived as credible the attitude towards the product will be positively influenced. Also a positive attitude will account for an increased purchase intention. The research shows that combining an engineer with a message containing strong arguments will be perceived as the most persuasive advertisement combination when selling a technical product, in this case a PV-installation. Also the integrity is more important than the ability and the benevolence of the engineer. Respondents feel that the engineer should provide honest and sincere advice that is based on logic and factual data.