Causality affects our perception of time; events that appear as causally related are perceived as closer together in time than unrelated events. This effect is known as temporal binding. One potential explanation of this effect is that causality slows an “internal clock” that is used in interval estimation. To explore this hypothesis, we first examined participants’ perceived duration of a range of intervals between a causal action and an effect, or between two unrelated events. If (apparent) causality slows the internal clock, then plotting perceived duration against actual duration should reveal a shallower slope in the causality condition (a relative compression of perceived time). This pattern was found. We then examined an interesting ...