Delivering tactile stimuli via mobile browsers: A method for remote multisensory research

Online methods are becoming an essential part of the behavioral scientist's toolkit. While the remote presentation of visual and auditory stimuli has been shown to be reasonably accurate (Bridges et al., 2020), less is known about the feasibility of delivering tactile stimuli via the browser. In this study, we extend remote experimentation to the tactile domain by replicating a well-established multisensory phenomenon - the redundant target effect (RTE) - using Android smartphones. The RTE, wherein response times are faster to multisensory (bimodal or trimodal) than unimodal stimuli, was robustly replicated in an online sample using a browser-based task. In addition to the behavioral replication, we evaluated the timing accuracy and precision of visual, auditory, and tactile (vibration) stimuli presented via mobile browsers. Visual and auditory stimuli exhibited small, consistent lags, while vibration stimuli showed a greater delay. Further analysis indicated that much of this delay was attributable to the gradual ramp-up of smartphone vibration motors, rather than limitations of the browser itself. These results support the feasibility of using consumer mobile devices to study tactile and multisensory processing in uncontrolled environments. The significance of the current manuscript is twofold: first, we demonstrate that scalable, at-home user studies can incorporate haptics without bespoke apps; second, we provide benchmark timing data to inform the feasibility of future research implementing tactile perception measures in remote behavioral research.