The perceived duration of vast spaces is mediated by awe.

Looking out over the Pacific Ocean or the Grand Canyon can lead to a sense of vastness. As a perceptual phenomenon, vastness poses a unique challenge because traditional measures of distance are not capable of explaining such large spatial extents. Vastness, however, may lead to a sense of awe, and awe, in turn, can dilate one's experience of time. Time, then, may be a meaningful proxy measure of vastness. Whether vastness is related to the perception of time and if the emotional experience of awe plays a role in that relation was explored herein. Across three experiments, we examined the relation between vastness, awe, and perceived time. In Experiment 1, participants reproduced the perceived duration of images varying in vastness and rated them in terms of the awe experienced as if they were in the spaces. Greater vastness led to higher awe scores and longer duration estimates, with awe mediating the relation between vastness and time. Experiment 2 assessed if the average brightness of images, absent of scene structure, explained changes in perceived duration. Brightness did not explain variance in perceived duration; thus, the scene structure of vast scenes may play a role in altering perceived time. Experiment 3 examined if scene semantics could explain changes in perceived duration. Whereas the relation between vastness and perceived duration vanished, a weak, mediated effect still occurred. Ultimately, time may not be a proxy measure of vastness, but we find evidence that emotion can link the relation between spatial and temporal perception.