The role of the mirror-image reversal effect in reducing the peak shift and area shift along the angularity dimension

Pigeons trained monocularly and tested with the trained eye along the angularity dimension were found to show enhanced area shifts when compared to pigeons trained and tested binocularly. Pigeons trained monocularly and tested with the untrained eye showed reversed peak shifts in the direction of S?. These findings are consistent with the hypothesis that the mirror image of S? in angularity gradients functions to reduce the likelihood of the peak shift and area shift along the angularity dimension in pigeons, and question the use of the angularity dimension for intradimensional discrimination training and generalization testing.