Time without clocks.

Zeiler (1999) wrote a theory paper. It says animals do not use an inner clock.

Instead, they remember past events. Time is judged by how memories fade.

The paper lists no new data. It builds on older memory studies.

The main claim: timing is a memory job, not a timer job.

If a memory is strong, the interval feels short. If it is weak, it feels long.

Green et al. (1999) said the same thing in the same year. They also dumped the clock. Instead of memory, they point to reinforcement shaping neural circuits. Same fight, different weapon.

Webb et al. (1999) and Staddon et al. (2002) later added math. They built trace-decay equations that predict most timing curves. These papers extend D’s idea into formal models.

Lejeune et al. (2006) looked back and bundled all anti-clock papers, including D, into one review. The field keeps moving away from timers and toward memory or reinforcement accounts.

If your learner’s timing is off, check memory cues before you add visual timers. Strengthen earlier cues, space trials, or change reinforcer delay. These moves may fix the problem without buying extra equipment.