Perception of complex signals by unrestrained cats

The ability of cats to discriminate modulation parameters of linearly amplitude and frequency-modulated signals was investigated under conditions of free behavior of the animals. The maximum variations of the amplitude and frequency of the modulated signals for which the probability of discrimination is equal to the threshold (0.75) are 1.6 dB and 150 Hz for a carrier frequency of 2.5 kHz. Replacement of one type of modulation by the other in those cases when stimuli with supraliminal values of the modulation parameters (15 dB and 1 kHz) leads to random selection during discrimination of these signals by the animals. In the case of an analogous replacement of the type of modulation for signals with threshold values of the modulation parameters, the probability of discrimination becomes significant (p>0.05).Translated from Fiziologicheskii Zhurnal SSSR imeni I. M. Sechenova, Vol. 75, No. 9, pp. 1194–1199, September, 1989.