Temporal order can be assessed in a rather straightforward experimental manner. Research subjects can be provided sequential auditory clicks, one to each ear. If the clicks are one second apart, nearly all participants can correctly identify whether or not the click in the right ear came before the one in the left ear. It turns out that this holds true even if the clicks are only 100 milliseconds (0.1 seconds) apart. The threshold for being able to correctly assign a temporal order to such brief stimuli lies around 30 milliseconds for young adults (up to 25 years old) and 60 milliseconds for older adults.
Temporal integration of stimuli, on the other hand, cannot be directly measured through experiments. It is not possible to ask research subjects, “Are these two stimuli part of your now?” and expect a definitive answer because everyone has a different concept and definition of what constitutes “now” or the “subjective present.” Therefore, researchers such as Ernst Pöppel have had to resort to indirect assessments of temporal integration and ascertain what interval of time is grasped as a perceptual unit by our brain
