Neural basis of redundancy effects in visual object categorization.

Bilateral redundant information often leads to improved detection performance compared to only unilateral input. This experiment investigates redundancy effects at the level of object processing in behavioral and functional imaging data. Subjects received different combinations of categorical information presented to both visual hemifields simultaneously. For pictures of faces as well as for pictures of buildings, response latencies were faster when two pictures from the same object category were presented compared to two pictures from different categories. This behavioral advantage was accompanied by increased activation in the respective object-selective areas, i.e. in the Fusiform Face Area (FFA) for pictures of faces and in the Parahippocampal Place Areas (PPAs) for pictures of buildings. These results suggest an involvement of visual object-selective areas in the behavioral redundancy gain.