Microgenesis as traced by the transient paired-forms paradigm.

Two successive, spatially overlapping human faces were exposed for recognition with SOAs ranging from 20 to 160 msec. The subjects effectively perceived one face, which at short SOAs mostly resembled the first stimulus and with increasing SOAs gradually shifted towards the appearance of the second, dimmer stimulus. These results replicated those from the study by Calis, et al, and extended them to the experimental conditions of controlled simultaneity of each of the two temporally separate, extremely brief stimuli and to the conditions of personally unfamiliar stimulus-subjects. In the second experiment we employed a direct measurement of the microgenetic focus in real time by using a procedure by which the subjects' judgments about the relative temporal order of the critical visual stimulus and an auditory click were recorded. Via this procedure it was shown that one of the effects of the first visual stimulus is to speed up the microgenetic process for the second stimulus which then appears subjectively earlier as compared to the single-stimulus control.