Methods and devices for applying at least one manipulative action to a selected content object are disclosed. In one aspect, a head-mounted-device (HMD) system includes at least one processor and data storage with user-interface logic executable by the at least one processor to apply at least one manipulative action to a displayed content object based on received data that indicates a first direction in which the HMD is tilted and an extent to which the HMD is tilted in the first direction. The at least one manipulative action is applied to a degree corresponding to the indicated extent to which the HMD is tilted in the first direction.