Since Hartline described lateral inhibition in the the 1930's, lateral inhibition has been assumed to shape receptive field selectivity in many sensory domains. In visual cortex, lateral inhibition -- in the form of cross-orientation inhibition -- has been invoked to explain the sharpness of orientation tuning, cross-orientation suppression, contrast invariance of orientation tuning, and other nonlinear properties of cortical neurons. Intracellular recording from cortical neurons suggest, however, that the behavior of cortical simple cells can be accounted for by a simple feed-forward model, one that lacks lateral inhibition, but that incorporates the nonlinearities of the visual pathway, such as contrast saturation, rectification, neuronal threshold, and trial-to-trial variability of responses.