Is accuracy feedback necessary for visual perceptual learning to occur?

No, explicit accuracy feedback is not necessarily required for visual perceptual learning to occur. While the learning process tends to be more gradual when feedback is absent, improvements in visual sensitivity and performance can still be achieved through practice alone.1

It is important to distinguish this from other forms of learning, such as psychomotor learning, where the acquisition of skill generally requires relevant feedback to avoid the extinction of correct responses and the proliferation of errors. In the context of visual perceptual tasks, however, research indicates that the visual system is highly mutable and capable of refining its processing through repeated exposure to stimuli, even without external information regarding the accuracy of a response.21