Pulling smartphones. An app-based approach-avoidance task

Abstract

We developed and successfully tested a mobile version of the approach-avoidance task (AAT). Approach-avoidance motivations play an important role in a variety of health-related behaviours, ranging from addictions to eating behaviours. The classical AAT has long been a useful tool to measure as well as train these motivations. However, the hardware required to set up the AAT has so far restricted research to the laboratory. To overcome this limitation we developed a mobile version of the AAT which runs entirely on a regular smartphone. Here, we tested 64 participants with both the classical AAT and the mobile AAT. Participants approached and avoided pictures of happy and angry faces by pulling or pushing a joystick (classical AAT) or a smartphone (mobile AAT) towards or away from themselves. Reaction times and reaction forces were measured. The mobile AAT successfully detected a known approach-avoidance effect, in which participants pulled happy faces faster than angry faces, but pushed happy faces slower than angry faces (p<0.001, η2_partial=0.266). Additionally, with the mobile AAT, we were the first to detect an approach-avoidance effect on movement force. Participants used more force to pull happy faces than angry faces but less force to push happy faces (p=0.006, η2_partial=0.131). Given these exciting results, we believe that the mobile AAT will provide a powerful tool for health professionals to research and to train approach-avoidance motivations in the field. One of these field studies, in which we measure approach-motivations towards healthy and unhealthy foods, is currently under way.