Studying reaction time with nonaging intervals: An effective procedure

The nonaging-intervals procedure, in which momentary probability of stimulus occurrence remains constant, is preferable in principle to varied or constant intervals for double-stimulation experiments on reaction time (RT). However, elevation of RT has uniformly been found at short waiting intervals on single-stimulation baseline tasks. Effects attributable to the first stimulus on double-stimulation tasks would thus be confounded. The required level baselines were obtained for both simple and choice reactions by combining the transit-signal method with nonaging intervals. Possible reasons for this success were the elimination of timekeeping error and psychological refractoriness. Results with precued full response information show the expected decline of RT with increase of precue-to-stimulus interval. Suggestions are given for the use of nonaging intervals for studying the attentional demands of movements and the influence of level of momentary probability on basic RT effects.