No anchoring effect in temporal momentum effect: Evidence from a comparison paradigm

The temporal momentum effect (TME) refers to a systematic distortion in temporal arithmetic whereby addition tends to produce overestimation and subtraction tends to produce little underestimation or no bias. Previous investigations have relied predominantly on reproduction paradigms, leaving open whether the effect reflects motor processes or more general aspects of temporal cognition. Across two experiments, we examined the TME using a psychophysical comparison staircase paradigm, which minimizes motor demands. In Experiment 1, participants underestimated addition outcomes and overestimated subtraction outcomes. Although this pattern appears reversed relative to reproduction tasks, it corresponds, when expressed in terms of subjective duration, to the classical TME. In Experiment 2, we tested whether the TME could be explained by anchoring effects arising from differences in operand ranges across operations. To this end, we varied whether the longer duration appeared first or second in addition problems. No effect of operand order emerged, indicating that anchoring on the first operand cannot account for the TME under these conditions. Taken together, these results suggest that TME-like biases can also emerge in comparison paradigms and are therefore not restricted to reproduction procedures alone. More broadly, the findings are compatible with the idea that the TME reflects biases arising during the mental manipulation of temporal intervals, although the mechanisms underlying these distortions remain to be established.