Source of Expertise Affects Perceived Credibility of an Interview Used in a Medical Documentary

Abstract

This thesis is composed of two integrated components: a creative project and original academic research. The creative component is a 25-minute medical documentary called Fairy Steps. Fairy Steps follows a 4-year-old girl with Cerebral Palsy who is trying to get to St Louis, in America to have a surgery called Selective Dorsal Rhizotomy (SDR) that may help her walk for the first time. There were difficulties finding New Zealand health professionals willing to be interviewed for Fairy Steps but a timely holiday visit to New Zealand provided an opportunity to film the American surgeon. The challenge of finding experts willing to be interviewed and a paucity of research into credibility of different sources of expertise provided the impetus for the academic research.

The academic component involved original research into the use of interviews in Fairy Steps, and how this storytelling device affects viewers’ perceptions of source credibility, empathy towards the characters and engagement with the content. This was tested with an intervention where 328 individuals were divided into two conditions. Each was shown one of two 30-second videos. The video was an excerpt from Fairy Steps; the same individual was shown in both videos in which the condition of Cerebral Palsy was briefly, accurately and articulately described. In one condition, the interviewee was labelled correctly as the mother of a child with the condition of Cerebral Palsy; in the other condition, the interviewee was labelled as a neuroscientist. Both labels were deemed plausible in pilot testing. Measures of viewer perceived credibility, empathy and engagement were assessed by pre-test and post-test survey questions in each group and compared between conditions. There were no differences in viewer engagement or empathy between the conditions. There was a significant difference in participant responses to two of the credibility questions, regarding the interviewees’ experience and expertise. Participants were more likely to “Strongly agree” that the Mother had more experience. Participants were comparatively more firm in their belief that the Scientist was an expert in Cerebral Palsy than the Mother.

This research has implications for the use of interviews for factual communication. Viewers are frequently using media as a source of learning about health-related information. The current research has indicated that source identity has effects on viewer perceptions of source credibility. Source credibility is essential to viewers making well informed decisions about their health. Given this, this research indicates that the choice of expert can impact how effective the message is in a documentary and have wider consequences for the viewer. As such when using this medium for health communication it is crucial that filmmakers think about who is the most appropriate expert to effectively communicate their message and whether this expert should necessarily be a Health Professional.