In many of the studies that I have read or participated in, I have seen that they show a blank screen between two stimuli. For example, in this study by Cohen et. al. 2017, a training paradigm is used where a flanker task is shown followed by a blank screen for (1000 - Reaction Time) ms followed by an emotional/neutral image. I've cited this study just as an example, I've seen similar blank screens in many other studies. My question is what is the reason for showing the blank screen? What would have happened if they showed the emotional/neutral image right after the flanker task?

One reason I can think of is that it is shown to keep the starting point of different stimulus constant between different participants. Is there any other reason? Please let me know.