Background: Online communities and social networking sites have
great potential for supporting health behavior change. However,
interventions vary greatly in participants’ engagement rates and,
consequently, their effectiveness. Theory-based interventions in
real-world contexts are needed to further increase engagement
and effectiveness.
Methods: We experimentally tested whether a video intervention
teaching Self-Determination-Theory-based communication strategies
increases need-supportive communication strategy use over one
week (Study 1, N = 76) and perceived need support, engagement,
and goal attainment in a behavior change intervention supported
by a forum-based online community (Study 2, N = 537). In Study 2,
participants chose a goal (increasing either fruit or vegetable
consumption or increasing moderate or vigorous physical activity)
and joined an online community for 2 weeks. Data from both
experiments were analyzed with mixed models and follow-up tests.
Results: In Study 1, participants in the intervention but not in the
control group showed an increase in the number of need-
supportive communication strategies used both immediately and
one week after the intervention (condition × time interaction, partial
η2 = 0.31). In Study 2, participants who watched the intervention
video had a higher number of postings and reported a higher
subjective forum use frequency (but not a higher number of logins)
compared to participants who watched the control video. However,
the effect on the subjective forum visit frequency was not robust.
There were no intervention effects on perceived need support, goal
attainment, or secondary outcomes. The results might be explained
by low application of need-supportive communication strategies.
Conclusion: A brief video intervention may be a suitable, low-cost
intervention to promote need-supportive communication strategy
use, benefitting both engagement and behavior change. Future
studies should incorporate additional means to further improve
communication strategy uptake and engagement in online
communities.
