[Differences in the perception of periodic and non-periodic visual stimuli in rhesus macaques]

Differences in perception of periodic and non-periodic visual stimuli were studied in rhesus monkeys during elaboration of an instrumental reflex. In the process of learning selectivity was formed (within the frequency band of 0.5 = 1 octave) for each spatial frequency used as positive stimulus. The selectivity to a definite bar width was less expressed, and a more prolonged learning was needed for its formation. There was no complete transfer from the positive grid frequencies to stimuli consisting of one or two bars with a width equal to a half-period of these frequencies. The distributions of choices acquired in the process of differentiation of vertical stimuli were preserved when their orientation was changed to the horizontal one for bars of definite width. This fact points to a complete transfer of this selectivity, while its considerable widening for spatial frequencies testifies to the absence of complete transfer of frequency selectivity.