This is because temporal uncertainty, or the feeling of not knowing when something will happen, can slow the passage of time. As adults, many of us have significant experience of this.
Think back to the last time the train inexplicably stopped just outside the station, or when the “wait” sign flashed endlessly in baggage reclaim after a flight. I bet neither of these delays flew by quickly – and that an update from the train driver or airport staff would have been very welcome in these moments. It’s the not knowing, the lack of control, that causes these events to drag.
When there is uncertainty about time, monitoring it becomes a priority. Humans have limited cognitive capacity and can’t pay attention to everything all of the time. We, therefore, prioritize what we process depending on our circumstances.
When time becomes uncertain we pay far more attention to it than normal, and this results in the sensation that time is passing much more slowly. Time is more often uncertain for children, so without something to distract themselves, they’ll fixate on the progress of any journey.
A watched pot never boils
Finally, time in the car may drag for kids simply because they’re cooped up with nothing to do but stare out of the window. That’s a trial of boredom for children, while their parents in the front are likely savoring the opportunity to just sit and reflect.
Children’s desire for stimulation and entertainment means that boredom often sets in quickly, and this boredom also slows the passage of time. Like temporal uncertainty, our level of boredom affects our experience of time by altering the amount of attention that we pay to it.