We formulate a comprehensive theory that accounts for variation in the perception of time. According to our theory, lived time is perceived to pass slowly (protracted duration) when conscious information processing is high; lived time is perceived to be synchronized with clock time (synchronicity) when conscious information processing is moderate; and lived time is perceived to have passed quickly (temporal compression) when conscious information processing is low. We examine that portion of the theory concerning temporal compression in light of empirical materials. Since episodic memory erodes as time passes, we hypothesize that this generates the experience of temporal compression by lowering the density of conscious information processing. Our data were drawn from three different age cohorts, and we find strong support for the hypothesis.