Abstract
Previous studies have found that, in experiments that present two stimuli at relatively short inter-stimulus intervals (ISIs)/stimulus onset asynchronies (SOAs), temporal uncertainties tend to be greater as the ISIs/SOAs becomes shorter when using a within-block design, and that temporal uncertainties influence various measurements. The present study aims to show that the temporal-uncertainty bias elicits priming experiment results that are inconsistent with spreading activation theory. We manipulate SOAs in a within-block design in Experiment 1 and in a between-block design in Experiment 2. We first measure simple reaction times reflecting temporal uncertainty at each SOA condition, and also lexical decision times for each experiment. The results reveal that, in the within-block design, simple reaction times were longer at shorter SOAs, which suggests that temporal uncertainties are larger at shorter SOAs, and that priming effect changes according to the SOAs were inconsistent with spreading activation theory. Rather, the results indicate that simple reaction times were equal at all SOAs in the between-block designs, which suggests that temporal uncertainties are constant, and that priming effect changes were consistent with spreading activation theory. Finally, the necessity of considering temporal uncertainty is discussed.
