Trainees are selected between the ages of 20 to 25 after a strict medical examination, part of which is conducted in a room subject to controlled air pressure. Intelligence and psychological tests are also given. Many applicants are eliminated in the preliminary examinations, only the superior candidates being chosen. At the Shibata training center, it is reported that two steel globular cages about 5 feet in diameter, with a seat inside and an opening at eye-level in front of the seat, are used in training parachutists to overcome giddiness and in rejecting those who prove unsatisfactory. A trainee is strapped in the seat, and the cage then rolled about. Immediately upon stopping, the candidate must read satisfactorily certain letters and figures which are held opposite the eye-level opening in the cage.