Reconsideration of ouija board motion in terms of haptic illusions (IV): effect of haptic cue and another player

The Ouija board game is associated with a type of involuntary motion known as an ideomotor action. We sought to clarify the conditions under which this motion occurs by evaluating the effect that visual and haptic movement cues have on its occurrence. Using our lateral skin deformation device, we found that the simultaneous presentation of visual and tactile illusory motion and force produced larger ideomotor actions than when either modality presented alone, an effect that was further potentiated by the presence of another player (an avatar).