Which of the following enhances perceptual features of a stimulus, according to the information processing model?

Using visual aids during training enhances perceptual features of a stimulus by leveraging visual input to clarify and reinforce the information being presented. Visual aids, such as diagrams, charts, or videos, can help learners more readily grasp complex concepts by presenting information in an engaging and easily digestible format. In the context of the information processing model, visual aids serve to enhance the sensory input that learners receive, making it easier for them to process and retain that information.

While the other options may contribute to the learning experience in various ways, they do not directly enhance the perceptual features of the stimulus as effectively as visual aids. Feedback from trainers can help learners understand their performance but may not modify the stimulus itself. Variability in stimulus exposure can improve adaptability but may not enhance perception directly. Providing learner expectations can prepare individuals for what they will encounter but does not alter the perceptual aspects of the stimuli being presented. Therefore, using visual aids stands out as the option that specifically enhances the perceptual features of stimuli in alignment with the principles of the information processing model.