Sarah Elbert

A Mobile Phone App Intervention Targeting Fruit and Vegetable Consumption : The Efficacy of Textual and Auditory Tailored Health Information Tested in a Randomized Controlled Trial

Background Mobile 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. Objective In 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. Methods After 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. Results In 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). Conclusions This 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. ClinicalTrial International Standard Randomized Controlled Trial Number (ISRCTN): 23466915; http://www.isrctn.com/ISRCTN23466915 (Archived by WebCite at http://www.webcitation.org/6hTtfSvaz)

An experimental test of the relationship between voice intonation and persuasion in the domain of health

Objective: In the process of behaviour change, intonation of speech is an important aspect that may influence persuasion when auditory messages are used. In two experiments, we tested to what extent different levels of intonation are related to persuasion and whether for some recipients the threat posed by the message information might become too strong to face. Design: In Study 1, 130 respondents listened to a health message with either a low, moderate or high level of intonation. In Study 2 (N = 143), the same manipulations of intonation were applied but half of the respondents were affirmed before they listened to the persuasive message. Intention to increase fruit and vegetable intake was used as a dependent variable. Results: Both studies showed that high intonation led to a significant drop in intention among respondents who perceived their own health as good. After self-affirmation, persuasion was increased. Conclusion: 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.

Effects of tailoring ingredients in auditory persuasive health messages on fruit and vegetable intake

Objective: Health messages can be tailored by applying different tailoring ingredients, among which personalisation, feedback and adaptation. This experiment investigated the separate effects of these tailoring ingredients on behaviour in auditory health persuasion. Furthermore, the moderating effect of self-efficacy was assessed. Design: The between-participants design consisted of four conditions. A generic health message served as a control condition; personalisation was applied using the recipient’s first name, feedback was given on the personal state, or the message was adapted to the recipient’s value. Main outcome measures: The study consisted of a pre-test questionnaire (measuring fruit and vegetable intake and perceived difficulty of performing these behaviours, indicating self-efficacy), exposure to the auditory message and a follow-up questionnaire measuring fruit and vegetable intake two weeks after message exposure (n = 112). Results: ANCOVAs showed no main effect of condition on either fruit or vegetable intake, but a moderation was found on vegetable intake: When self-efficacy was low, vegetable intake was higher after listening to the personalisation message. No significant differences between the conditions were found when self-efficacy was high. Conclusion: Individuals with low self-efficacy seemed to benefit from incorporating personalisation, but only regarding vegetable consumption. This finding warrants further investigation in tailoring research.

Reading or Listening to a Gain- or Loss-Framed Health Message: Effects of Message Framing and Communication Mode in the Context of Fruit and Vegetable Intake

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.