Abstract
The purpose of this study was to evaluate models of attentional switching mechanism between two ears through reaction time (RT). In two experiments, eight or 12 subjects were required to judge whether frequencies of two tone pips presented successively were the same or different. RTs obtained when two tones were presented to the same ear (Condition NS) were compared with those obtained when two tones were to the different ear (Condition S). In Exp. I, two tones (1000Hz or 1030Hz) were presented with 100, 200, 400, 800 and 1600ms ISI. Exp. II was designed to clarify the effect of the task difficulty upon differences in RTs between Conditions NS and S, with 100, 200, and 400ms ISIs. The task difficulty was defined by the degree of frequency differences in two tones. Throughout Exp. I and II, the RTs of Condition S were longer than those of Condition NS at short ISIs but not at long ISIs. These RT differences were independent of the task difficulty. These results suggested the existence of the attentional switching mechanism and supported the structural models rather than capacity models of attention.
