VISUAL MEMORY SYSTEMS IN THE CEREBRAL HEMISPHERES

The brain systems that underlie the ability to recognize different types of visual forms and the ability to recognize specific instances of the same type of form will be examined in the proposed research. An abstract- visual-form (AVF) system underlies recognition of different types of visual forms and operates more effectively in the left cerebral hemisphere (LH) than in the right cerebral hemisphere (RH). In contrast, a specific- visual-form (SVF) system underlies recognition of specific instances of a type of form and operates more effectively in the RH than in the LH. The proposed experiments will be conducted to further test whether these systems operate relatively independently in the brain. More importantly, the experiments are designed to test whether structural description characterizes the operations in an AVF system and whether template matching characterizes the operations in a SVF system. If so, the results from divided-visual-field studies of visual repetition priming should indicate that the parts of a visual form are stored and processed more effectively when the visual information is presented directly to the LH than to the RH, whereas the global structure of a visual form is stored and processed more effectively when the visual information is presented directed to the RH than to the LH.