Recognition of lateralized halftone and outline images of everyday objects in conditions of masking.

Recognition of the shapes of halftone and outline images of everyday objects in conditions of lateralized tachystoscopic presentation and different levels of noise masking (with "raindrops") by humans was studied. Mean group data for 15 subjects demonstrated significantly better recognition of outline images of everyday objects by the left hemisphere of the brain than the right at all levels of masking. Increases in masking produced gradual and significant degradation of recognition as compared with controls (recognition of unmasked figures). Recognition of outline images at all levels of masking was significantly better than recognition of halftone images of the same objects. In men, there were no significant differences between hemispheres either at different levels of masking or for different types of stimuli. The neurophysiological mechanisms and functional significance of these effects are discussed.