2011 年 70 巻 2 号 p. 115-121
We are planning an experiment to determine why and how we perceive tilt in space. Tilt perception was thought to disappear in space, where gravity does not exist as a reference for tilt. Nevertheless, astronauts reported perceived head roll-tilt and ocular counter-rolling (OCR) in a centrifuge experiment in space. To explain these unexpected findings, during long-term space life we will measure the subjective visual body axis (SVBA) and OCR at various body roll-tilt angles relative to the inner-cabin vertical, with and without head roll-tilt relative to the body, with and without visual information. We are also currently performing ground-based experiments to collect control data. In this article, we introduce these space and terrestrial experiments.