It has been suggested that high concentration or flow experience alters the sensation of time. Additionally, attention is known to affect the perception of time. To investigate whether the effect of concentration on time perception is equivalent to that of attention, we investigated the correlation between subjective concentration and the judgment of temporal duration through 3 experiments employing 8 everyday tasks. The results showed that concentration rating was not significantly correlated with duration estimates in ordinary time units and was negatively correlated with categorical duration judgment. With the feedback of physical elapsed time, categorical duration judgment eliminated the correlation, suggesting that concentration was correlated with duration judgment only when the participants did not have access to information concerning duration. Unlike attention, concentration had an effect on subjective time impression but not on duration estimation, suggesting that it affects time perception differently from effort-based mechanisms.

Key words: concentration, time perception, flow experience, attention, effort