BackgroundMobile phone apps are increasingly used to deliver health interventions, which provide the opportunity to present health information via different communication modes. However, scientific evidence regarding the effects of such health apps is scarce.ObjectiveIn a randomized controlled trial, we tested the efficacy of a 6-month intervention delivered via a mobile phone app that communicated either textual or auditory tailored health information aimed at stimulating fruit and vegetable intake. A control condition in which no health information was given was added. Perceived own health and health literacy were included as moderators to assess for which groups the interventions could possibly lead to health behavior change.MethodsAfter downloading the mobile phone app, respondents were exposed monthly to either text-based or audio-based tailored health information and feedback over a period of 6 months via the mobile phone app. In addition, respondents in the control condition only completed the baseline and posttest measures. Within a community sample (online recruitment), self-reported fruit and vegetable intake at 6-month follow-up was our primary outcome measure.ResultsIn total, 146 respondents (ranging from 40 to 58 per condition) completed the study (attrition rate 55%). A significant main effect of condition was found on fruit intake (P=.049, partial η2=0.04). A higher fruit intake was found after exposure to the auditory information, especially in recipients with a poor perceived own health (P=.003, partial η2=0.08). In addition, health literacy moderated the effect of condition on vegetable intake 6 months later (P<.001, partial η2=.11). A higher vegetable intake was found for recipients with high health literacy after exposure to the textual or auditory intervention compared to the control condition (contrasts P=.07 and P=.004, respectively). In the case of relatively low health literacy, vegetable intake was the highest in the control condition (contrasts text control: P=.03; audio control: P=.04).ConclusionsThis study provides evidence-based insight into the effects of a mobile health app. The app seems to have the potential to change fruit and vegetable intake up to 6 months later, at least for specific groups. We found different effects for fruit and vegetable intake, respectively, suggesting that different underlying psychological mechanisms are associated with these specific behaviors. Based on our results, it seems worthwhile to investigate additional ways to increase fruit and vegetable intake in recipients with low health literacy.ClinicalTrialInternational Standard Randomized Controlled Trial Number (ISRCTN): 23466915; http://www.isrctn.com/ISRCTN23466915 (Archived by WebCite at http://www.webcitation.org/6hTtfSvaz)

Gain-framed health messages are found to be more effective when targeting prevention behaviors. However, framing research has only minimally investigated the role of communication mode, another important factor in health communication. This study explored the role of communication mode in interaction with message framing, and the influence of two individual differences related to involvement as conditions under which gain framing can lead to health behavior change. Participants (N = 258) were exposed to either an auditory or written health message concerning fruit and vegetable intake, with either gain- or loss-framed arguments. In addition, the online experiment consisted of baseline and posttest measures, among which intention to consume sufficient fruit and vegetables. Moderating effects of perceived baseline fruit and vegetable consumption and baseline intention were assessed. A significant interaction between message framing and communication mode was observed: In case of a gain-framed message, an auditory message resulted in a higher intention than a written message. This pattern was most explicitly found among those with a lower perceived fruit and vegetable intake at baseline. Although further research is warranted in health persuasion research, the findings can possibly be used to target health interventions better at specific groups of people who behave less healthy.

A high level of intonation seems to induce self-regulatory defences in people who do not see the necessity to change their health behaviour, whereas people with poor perceived health might perceive potential to change. The use of a normal level of intonation in auditory health messages is recommended.

Objective: Because the working memory (WM) has a limited capacity, the cognitive reactions towards persuasive information in the WM might be disturbed by taxing it by other means, in this study, by inducing voluntary eye movements (EMi). This is expected to influence persuasion. Methods: Participants (N ¼ 127) listened to an auditory persuasive message on fruit and vegetable consumption, that was either framed positively or negatively. Half of them was asked to keep following a regularly moving dot on their screen with their eyes. At pretest, cognitive self-affirmation inclination (CSAI) was assessed as individual difference to test possible moderation effects. Results: The EMi significantly lowered the quality of the mental images that participants reported to have of the persuasive outcomes. With regard to self-reported fruit and vegetable consumption after two weeks, EMi significantly lowered consumption when CSAI was high but it significantly increased consumption when CSAI was low. Conclusions: The results verify our earlier findings that induced EM can influence persuasion. Although it remains unclear whether the effects of EMi were caused by disturbing mental images of persuasive outcomes or self-regulative reactions to these images, or both, the WM account may provide new theoretical as well as practical angles on persuasion.

Persuasive health messages can be presented through an auditory channel, thereby enhancing the salience of the source, making it fundamentally different from written or pictorial information. We focused on the determinants of perceived source reliability in auditory health persuasion by investigating it from two distinct angles. First, inferences on the voice (pleasantness) and person (e.g., similarity) significantly predicted perceived source reliability. In a second (experimental) study, three contextual factors (message framing, level of processing, gender matching) affected perceived reliability independently. Furthermore, perceived reliability mediated the effect of message framing on persuasion. The evaluation on source reliability in auditory persuasion seems to be affected by several factors, partly unique to auditory communication. These studies may inspire further research on auditory (health) persuasion.Health information is mostly communicated through text and images and might be presented as a reminder on a package of cigarettes or as a health message on television. However, health information can also be presented through an auditory channel. A classic form of auditory communication is the radio, which is available all over the world. Research shows that 84.8% of the American people older than 12 years listen to the radio on a daily basis (Downey, 2002; e.g., similar high percentages are found in the United Kingdom (RAJAR, 2014)). In addition, the use of online radio is on the rise (Webster, 2011). Moreover, new technological developments facilitate the use of auditory channels. In particular, MP3 is a technological advancement broadly disseminated in modern society and used by millions of people. It is now included in easy portable MP3 players, smartphones, and tablets, which makes the potential value and reach of MP3 as a channel of auditory information enormous.The present studies are on auditory health persuasion in which recipients listen to a voice that provides information concerning healthy behaviors.