How can practice improve the accuracy of judging distances and odour intensities?

Through perceptual learning, practice improves the accuracy of sensory judgments by modifying how the brain processes and represents stimuli.1

For judging distances, research indicates that practice enhances precision in absolute judgments. In studies where subjects estimated varying distances, those who engaged in extra practice—by estimating a series of different distances—showed significantly improved accuracy and reduced variability compared to those who did not. Similarly, practice allows observers to detect spatial details, such as the separation between parallel bars, at increasing distances.2

Regarding odour intensities, practice has been shown to increase the precision of absolute judgments. The underlying mechanisms for such improvements often involve changes in neural processing, such as an increase in the size of neural representations or the sharpening of neuronal tuning functions. In some olfactory tasks, practice also leads to an increase in the synchronicity of neuronal firing, which serves as a strategy for the brain to represent learned information. These improvements occur even when subjects are not explicitly informed of their accuracy, though feedback can provide additional benefit.21