Why can perceptual learning occur even when observers are not told whether their answers are correct?

Perceptual learning can occur without explicit accuracy feedback because the process relies on sensory interaction with the environment and repeated practice in performing specific sensory tasks. While explicit feedback can accelerate the learning process, it is not strictly necessary for improvements in perceptual performance to take place.1

When observers engage in tasks such as visual acuity training, the brain undergoes physiological changes that improve the ability of sensory systems to respond to stimuli. These changes occur at both behavioral and neural levels, such as the sharpening of neuronal tuning functions or increases in the size of neural representations. Because these systems are highly mutable, the brain can reorganize and tune its neural mechanisms through the mere experience of interacting with stimuli, even in the absence of external confirmation regarding the correctness of a specific response. Consequently, while learning is more gradual without explicit feedback, the sensory system remains capable of refining its processing through consistent exposure and practice.1