Abstract: This paper examined the effects of perceptual grouping,locational uncertainty, andshmulus positions in the visual field on the processing of global and local propertiesof compound stimuli. It was found that (1)when compound stimui were presentod on awhite background, RT and interference displayed a global advantage. The globalinterference was eliminated by locational uncendnty. When compound stimuli werepresented on a background made up of " +" patterns, the local processing dominatedthe global processing. Locational uncertainty slowed local responses. (2)RTs to thecompound stimuli were longer when stimuli were displayed in the peripheral than thecentral visual fields. This effect was larger for local RTs than for global RT. (3)therewere no differences between responses to compound stimuli presented in the left andright visual fields. The authors suggested that the background " +" weakened globalprecedence through eliminating proximity grouping of local elements and making shapesimilarity dominate grouping. This paper also discussed the effect of other factors onthe processing of compound shmuli.

Key words: compound stimulus, visual perceptual grouping, locational uncertainty, global property, local property