Karl von Vierordt in 1868 was the first to record a law of time perception which relates perceived duration to actual duration over different interval magnitudes, and according to task complexity.

This article relies largely or entirely on a single source. (July 2022)

Vierordt's law is "a robust phenomenon in time estimation research that has been observed with different time estimation methods".^[1] It states that, retrospectively, "short" intervals of time tend to be overestimated, and "long" intervals of time tend to be underestimated. The other major paradigm of time estimation methodology measures time prospectively.

• Hofstadter's law – Self-referential adage referring to time estimates