Contrast threshold for a sinusoidal target in the simultaneous presence of the vertically displaced peripheral gratings was measured as a function of the peripheral contrast and the separation. When the signal and peripheral gratings were in phase, the low-contrast peripheral gratings produced the improvement in signal threshold, while the high-contrast gratings produced threshold elevation. The facilitation effect was extended to the separation equating to 10 grating cycles, whereas the inhibition effect was restricted to the region near the border. When the two gratings were out of phase, the low-contrast peripheral gratings produced threshold elevation, while the high-contrast gratings exerted little effect on signal threshold. The results were explained in terms of spatial summation and lateral inhibition.
Female Form Perception