The difference observed between the experiments cannot be attributed to a difference in difficulty due to the timing of stimuli associated with reduced stimulus durations, because both stimulus durations and response time deadlines were identical in Experiments 1 and 3. Instead, this outcome is likely to reflect the difference in the discriminability of the target and distractor stimuli in these two experiments. In Experiment 1, several pictures of gummy candies (rice crackers) were considerably similar to the pictures in the other category; therefore, participants misidentified the pictures of one category as those of the other category. In contrast, the discrimination between even and odd numbers was relatively easy, as indicated by the higher hit rate in Experiment 3 than that in Experiment 2. From this, and from the absence of differences in the false alarm rates and the mean reaction times, it is plausible to consider that the demand for response inhibition in Experiment 3 was not much different from that in Experiment 1.