Inhibitory mechanisms of attentional networks: Spatial and semantic inhibitory processing

Four experiments assessed the relationships between the orienting and the e xecutive networks of visual attention. Experiment 1 showed spatial inhibiti on of return (IOR) with target words. Experiment 2 showed a type of semanti c inhibition that mimicked spatial IOR. Reaction times to targets preceded by 2 consecutively presented words, the prime and the intervening stimulus, were longer when the target and prime were related than when they were unr elated. Experiment 3 combined spatial and semantic inhibition in a lexical- decision task. Spatial IOR was observed with both related and unrelated tar gets, but semantic inhibition was observed only when target words were pres ented in uncued locations. A similar interaction between IOR and positive s emantic priming was observed when the intervening stimulus was not presente d (Experiment 4). Implications for the relationships between the 2 attentio nal networks are discussed.