A right visual field advantage for tool-recognition in the visual half-field paradigm.

Neuropsychological and brain imaging studies have shown that the identification and use of tools mainly involve areas of the left hemisphere. We investigate whether this dominance can be observed in a behavioral visual half-field (VHF) task as well. To make sure that the VHF-effect was due to laterality and not due to attentional bias, we made use of two tasks: tool recognition and object recognition. On the basis of the existing literature, we predicted a right visual field (RVF) advantage for tool recognition, but not for object recognition. Twenty right-handed participants made judgments about whether one of two bilaterally presented stimuli was an object/non-object or a tool/non-tool. No VHF/hemisphere advantage was found for object recognition, whereas a significant RVF/left hemisphere advantage was observed for tool recognition. These findings show that VHF-tasks can be used as a valid laterality measure of tool recognition.