The threshold for successiveness

In Experiment 1, three stimuli were presented on each trial; the second and third were simultaneous. Ss said which of the three they saw first and then made a different second guess. Second guesses were correct more often than chance when first guesses were wrong, contradicting the predictions of a psychological moment theory. Psychometric functions are inconsistent with a theory which holds that Ss can order their perceptions and that errors result from lack of correspondence between this order and that of the stimuli. In Experiment 2, two pairs of stimuli, each simultaneous or successive, were presented on each trial, the interval between their onsets varying, and Ss guessed whether each was successive. A moment-like cyclic process affecting the perception of successive stimuli should raise the correlation between responses when both pairs were successive and beginning at the same time; this was not found.