DETERMINATION OF THE UPPER AUDITORY THRES HOLD IN HORSES BY OPERANT-CONDITIONING

The hearing ability of three horses, aged three to six years, was test ed by operant conditioning in the frequency range of ultrasound. It co uld be proved that signals with frequencies up to 3.8 . 10(3) cps were perceived. Because all the signals were supraliminal the lower audito ry threshold could not be defined by its sound pressure level. The hor ses do not perform well in operant conditioning requiring the manipula tion of objects due to their learning disposition.