Three subjective vertical tasks. (A) During a subjective visual vertical (SVV) task, participants orient a visually displayed bar with perceived vertical using an interfacing controller. (B) During a subjective postural vertical (SPV) task, participants either orient themselves with perceived vertical or are passively rotated until they indicate that they perceive themselves to be vertical. Here, a participant is shown standing on a motion platform that allows side-to-side tilt. Starting from a tilted platform orientation, the participant or experimenter will adjust the participant’s orientation. The participant will then indicate when his/her body is aligned with vertical. (C) During a subjective haptic vertical (SHV) task, participants align a hand-held object with perceived vertical.