That particular result can be explained without any difference in perception. If you ask people to count at a certain speed, you measure a skill. One that can

That particular result can be explained without any difference in perception. If you ask people to count at a certain speed, you measure a skill. One that can be mastered at any age. Of course unprepared participants of younger age are better prepared to tell the difference between 90 and 120 seconds. Their reward for being good at that is much higher. They are much more likely to take a short run and catch the train anyway. Split the participants into groups where they carry their watch (wrist, pocket, none) and you can "prove" that certain clocks have the power to create local time dilation.