Human attention research has demonstrated that vision dominates attention when vision is competing against audition under normal conditions, but that audition dominates attention under conditions of arousal set by electric shock. Two experiments were conducted to determine whether an attentional switching mechanism exists between the central and peripheral visual systems similar to that which exists between the visual and auditory modalities. In experiment 1, increasing subject's level of arousal by administering brief electric shocks resulted in attenuated central visual dominance of attention with a predictably located central stimulus and a randomly located peripheral stimulus. In experiment 2, where locations of both peripheral and central stimuli were unpredictable, peripheral visual dominance was observed in the aroused subjects. Non-aroused control groups in both experiments demonstrated central visual dominance. The results are discussed in terms of the adaptive significance of attentional switching mechanisms.