The spatial representation of time can be flexibly oriented in the frontal or lateral planes from an early age.

International audienceThe perception of time is strongly influenced by spatial context. The longer the distance of a stimulus’ trajectory, the longer its duration is perceived to be. This effect has primarily been investigated in the lateral (left-right) axis despite the fact that spatial metaphors for time most commonly invoke the frontal (front-back) axis. We therefore explored how spatial distance, depth, and direction influenced perceived duration of stimuli moving in the frontal or lateral axes. Moreover, we compared the developmental trajectories of frontal versus lateral representations of time by testing children (5, 7, or 10 years old) and adults. Results showed that perceived duration of the interval between 2 consecutive stimuli in a temporal bisection task was biased by distance in the frontal, as well as lateral, plane across all age groups. Even the mere impression of distance in depth (Ponzo illusion), was sufficient to produce these effects. These findings indicate that the spatial representation of time can be oriented flexibly in either frontal or lateral planes from the age of 5 years and even precedes the development of explicit timing mechanisms. Motion direction in the frontal plane (looming/receding) had little effect on perceived duration in adults, though children temporally underestimated looming stimuli, possibly due to attentional mechanisms