Health Promotion through Monetary Incentives: Evaluating the Impact of Different Reinforcement Schedules on Engagement Levels with a mHealth App

Background: Financial rewards can be employed in mHealth apps to effectively promote health behaviors. However, the optimal reinforcement schedule—with a high impact, but relatively low costs—remains unclear. Methods: We evaluated the impact of different reinforcement schedules on engagement levels with a mHealth app in a six-week, three-arm randomized intervention trial, while taking into account personality differences. Participants (i.e., university staff and students, N = 61) were awarded virtual points for performing health-related activities. Their performance was displayed via a dashboard, leaderboard, and newsfeed. Additionally, participants could win financial rewards. These rewards were distributed using a fixed schedule in the first study arm, and a variable schedule in the other arms. Furthermore, payouts were immediate in the first two arms, whereas payouts in the third arm were delayed. Results: All three reinforcement schedules had a similar impact on user engagement, although the variable schedule with immediate payouts was reported to have the lowest cost per participant. Additionally, the impact of financial rewards was affected by personal characteristics. Especially, individuals that were triggered by the rewards had a greater ability to defer gratification. Conclusion: When employing financial rewards in mHealth apps, variable reinforcement schedules with immediate payouts are preferred from the perspective of cost and impact.

Gamification Use and Design in Popular Health and Fitness Mobile Applications

Purpose: To evaluate the presence of gamification in popular mobile applications and whether principles from behavioral economics were incorporated in the design. Design: The top 50 ranked free health and fitness applications were downloaded. Gamification elements were predetermined through literature review, and applications were evaluated for their presence. Setting: App Store by Apple Inc. Measures: Presence of gamification, type of game element, and use of behavioral economic principles. Analysis: We classified the types and frequencies of targeted behaviors and features of gamification. Use of behavioral economic principles focused on designing rewards or points using loss aversion (allocated upfront and could be lost), variable reinforcement (not allocated constantly), and probability inflation (using drawings or lottery designs). Results: Gamification was used by 64% of mobile applications. Most applications that included gamification (97%) targeted behaviors related to physical activity and weight loss. Applications focused on other areas such as reproductive health, meditation, and sleep used gamification less often (11%). Game elements used most commonly included goal setting (78%), social influences (78%), and challenges (63%), while less common elements included points (6%) and levels (3%). No applications incorporated behavioral economics principles specified in the study. Conclusions: Gamification was commonly used by popular health and fitness mobile applications, but none used the specified behavioral economic principles to design rewards or points. Mobile applications could potentially improve their use if their design better leveraged principles from behavioral economics.

Behavior of Reinforced Retaining Walls with Different Reinforcement Spacing during Vehicle Collisions

Accidents involving vehicles crashing into reinforced retaining walls are increasing because of the increased construction of reinforced retaining walls on roads. Unlike a normal retaining wall, a reinforced retaining wall is not one united body but is made up of blocks. Hence, a reinforced wall can break down when a vehicle crashes into it. The behavior of such a wall during vehicle collision depends upon the reinforcement material used for its construction, its design, and the method of the construction. In this study, the behavior of a reinforced retaining wall was analyzed while changing the reinforcement spacing using LS-DYNA, a general finite-element program. Eight tons of truck weight was used for the numerical analysis model. The behavior of a reinforced retaining wall under variable reinforcement spacing and positioning was analyzed. The results indicated that the reinforcement material was an important resistance factor against external collision load.

Structural Behavior of a New GSZ Panel under Lateral Loads

Results of an experimental investigation to study the structural behavior of new GSZ panels are reported. Three half-scale new GSZ panels with variable reinforcement ratio were cast and tested under vertical loading and low cycle reversed horizontal loading. The failure process, strains in vertical steel bars and surface–concrete, load–displacement curve under increasing load were recorded and analyzed. Result obtained showed that the entirety performance of new GSZ panel is excellent. And the reinforcement ratio has a great influence on the lateral stiffness of the panel.

Nozzle Reinforcement: Constant vs. Variable

Section VIII Divisions 1 and 2 require shell openings to be reinforced using a cross sectional area replacement philosophy. Although the state of stress in a shell opening varies with the location along the nozzle to shell intersection most nozzle reinforcement is designed as though there is no variation. Openings in the shell which are reinforced with excess thickness available in the shell, nozzle neck, or weld are defined as “integrally reinforced.” Section VIII acknowledges the variation in stress for these integrally reinforced nozzles with respect to the orientation of a section cut through the opening. The use of a factor F to reduce the required reinforcement proportionally is allowed. In this paper, stresses developed due to internal pressure in integrally reinforced shell openings reinforced continuously are evaluated. These stresses are compared with those in the case where reinforcement is varied using the F factor. Continuously integrally reinforced nozzles have a constant amount of reinforcement area about the nozzle centerline while those reinforced with a variable area of reinforcement do not. This lack of symmetry is most likely to be developed through additional weld buildup on either the shell or nozzle neck or with a larger fillet on the attachment weld. The costs of each type of construction are compared. It is found that in some cases reinforcing a nozzle with a variable reinforcement area applied through weld buildup may be substantially less expensive than the typical reinforcing pad approach. A guideline of having 70% of the area required available within the shell and nozzle and weld is suggested as a criteria to evaluate the potential to benefit from a variable reinforcement approach.

REINFORCEMENT SCHEDULES AND THE MANAGEMENT OF CHILDHOOD BEHAVIOURS

Where a behaviour has been maintained on a variable schedule of reinforcement theoretically it should be possible to reduce resistance to extinction by first putting the behaviour onto a continuous schedule of reinforcement. This approach has been employed in animal research but rarely with human participants, and where it has, with little success. This study describes the use of the approach to overcome some minor problems in the behaviour of young children, the problems being sufficiently troublesome for the parents to consult their GP. All the families who used the approach were successful in remediating the behaviour. Some reasons for this success, in contrast with the disappointing outcomes of some of the earlier research, are discussed. Although the study lacks formal controls it is suggested that the approach could be usefully applied to other common childhood behaviours that have been subjected to variable reinforcement.