Rightward and leftward biases in temporal reproduction of objects represented in central and peripheral spaces

The basis for how we represent temporal intervals in memory remains unclear. One proposal, the mental time line theory (MTL), posits that our representation of temporal duration depends on a horizontal mental time line, thus suggesting that the representation of time has an underlying spatial component. Recent work suggests that the MTL is a learned strategy, prompting new questions of when and why MTL is used to represent temporal duration, and whether time is always represented spatially. The current study examines the hypothesis that the MTL may be a time processing strategy specific to centrally-located stimuli. In two experiments (visual eccentricity and prismatic adaptation procedures), we investigated the magnitude of the rightward bias, an index of the MTL, in central and peripheral space. When participants performed a supra-second temporal interval reproduction task, we observed a rightward bias only in central vision (within 3° visual angle), but not in the peripheral space (approximately 6-8° visual angle). Instead, in the periphery, we observed a leftward bias. The results suggest that the MTL may be a learned strategy specific to central space and that strategies for temporal interval estimation that do not depend on MTL may exist for stimuli perceived peripherally.