Differentiation for Novel Dimensions

Two experiments are reported that provide evidence for perceptual differentiation between a pair of novel, integral dimensions, in contrast to previous attempts that failed to differentiate these same two dimensions (Op de Beeck, Wagemans, & Vogels, 2003). In Experiment 1, an acquired distinctiveness effect was created on the category-relevant dimension through a categorization training regimen that gradually increased in difficulty. Response times for correct trials were faster across the category boundary. This effect was replicated in Experiment 2 using a new training procedure where participants had to predict category boundaries while watching an animation in which shapes transformed along the category-relevant dimension. Furthermore, the accuracy results of Experiment 2 also indicated that discriminability was changed on the category-relevant dimension relative to the irrelevant dimension across the entire range of the dimension, not just at the category boundary.