Chromatic perceptual learning

Perceptual learning has been shown on a wide variety of achromatic visual tasks. However, very little work has explored the possibility of improvements on chromatically based tasks. Here, we used a transfer of learning paradigm to assess the specificity of improvements at discriminating the orientation of a chromatically defined edge presented in luminance noise. Chromatic thresholds were estimated for two different hues and retinal locations, before and after a ten day training period. During training observers discriminated the orientation of a chromatic edge at just one location and hue. Whilst performance improved following training, these improvements failed to transfer across either retinal location or hue. Our findings suggest that improvements in chromatically-mediated discrimination may involve plasticity at early, retinotopically mapped, stages of visual analysis. Further, they suggest that categorical perception of colour might in part arise from chromatic perceptual learning at colour category boundaries.