Abstract
[Purpose] It has been well known that the perception of self-motion, especially linear vection, is induced by a visual stimulus under a condition that there is no information of physical acceleration along a direction of self-motion induced by an optical flow in a visual stimulus. That is, in most of cases, it is not necessary for gravity to be taken into account as an acceleration cue because its direction is the orthogonal to a moving direction. We investigated whether this condition as to acceleration is mandatory for the perception of vection. [Experiment] To test effects of physical accelerations in parallel to a moving direction in the perception of a linear vection, we measured duration of a delay (latency) up to the perception being induced. We used real world displays, edited commercial movies such that an observer is looking at around rails when sitting down in front of a train, because it is known that a real world display induces the perception more effective than more abstract one does. We varied a speed (114.1 to 342.3 km/h in the depth direction), and a direction (expansion and contraction, i.e., forward and backward locomotion) of optic flow in the real world display under conditions of a direction (same or opposite) of acceleration to a direction of the induced self-motion. [Result and Discussion] In contrast to our expectation, all observers perceived the linear vection under all experimental conditions in the real world display, although the latencies up to perceiving the vection were much longer than those to the conventional vection displays. The latency under the condition of the opposite direction of the acceleration was shorter than that under the same direction condition. These results suggest that inconsistent information of acceleration (the opposite to a moving direction) enhances to induce the perception of the vection.
Supported by the JSPS KAKENHI 22330204 to TY.