Visual Subliminal Cues for Spatial Augmented Reality

Augmented reality systems commonly employ overt cueing to direct a user´s attention and guide their actions. Spatial augmented reality based supraliminal annotations have been shown to improve user performance compared to LCD screens. This paper explores subliminal cues: annotations that exist below the threshold of consciousness. We investigate whether subliminal cueing is technically possible with standard data projectors, and if subliminal cues can further improve users´ reaction time in procedural tasks. This paper describes a new technique for temporal subliminal cues in spatial augmented reality, and presents the results of three user studies evaluating the effectiveness of this technique in a button-pressing task. The results show that the presentation of annotations is indeed subliminal, in that the visual stimulus was not perceivable to users. We found a statistically significant improvement in task performance when using subliminal cues and supraliminal annotations, compared to supraliminal annotations alone, with mean trial times improving from 633.49ms to 604.64ms.