Boredom makes time “drag,” but time “flies by” when we having fun. Time flies only in retrospect when you weren’t consciously “tracking” in the moment. You have a sense of change in your mind or in the objects around you during your “passage through things.” That’s how you can “lose track of time” driving home. Keele University psychologist John Wearden says your time perception is indirect: You perceive light when photons strike your eyes’ retinal cells; your sense of time depends on the light you see.
In experiments with timed rewards, dogs and rats show eerie time-span-learning abilities. “Scalar Timing in Memory,” a seminal 1984 paper, proposed what is known now as a pacemaker-accumulator or information-processing model which effectively a neural “clock with a memory.” Stimulants boost the clock’s speed, causing overestimated duration; depressants do the opposite. Separately, when Wearden primed people’s internal clocks with audio clicks, he found humans could react faster. Emotional state affects time perception; for example, curse words seem to flit by faster than non-expletives.
Arousal is the physiological preparation for action which is connected with strong emotions like anger. It appears to speed up the pacemaker-accelerator model, compressing more ticks into a given moment. Arousal also occurs when you unconsciously mimic someone else’s facial expression. An empathetic time perception connects you, creating a shared social distortion in how you both experience time. Parkinson’s disease causes time-interval misjudgments. Faulty interval timing also may prove to be a factor in autism. The “neuroscience of time” highlights its subjectivity. For example, take the common notion that time seems to pass more quickly for people as they age. Early “ratio theories” suggested this phenomenon relies on subjective judgment of a given duration -say, a year as a percentage of total life lived. Recent studies show this idea is folk wisdom, possibly instilled by the power of suggestion. At any age, time seems to pass more quickly when you’re busy and content.
Everyone struggles to focus on the present. With his Dasein (German for “one’s being” or “to be there”) concept, Heidegger suggested that you can’t really evaluate a life until it’s over. As in Augustine’s “tension of consciousness,” Heidegger said time is inextricably linked to the pull of the future. Newly aware of time’s passage, children start to ask about death at about the same time their sense of self coheres. In many ways, your attitude toward inevitable decay – like the dissolution of a sand castle – defines your “relationship to time” and to how you live your unique, time-constrained life.