Time perception is (only) mildly affected by spatial distance and tool-use training in young and older adults

Recent studies suggest that our perception of time is tied to the embodiment of space. They suggest that time is perceived or reproduced differently for stimuli at different distances from our body, and differently prior to and after an interaction with space using tools. To corroborate these findings, we performed a series of experiments in physical and virtual setups, testing 282 younger (18-35 years) and elderly (60-75 years) participants on a time reproduction task for stimuli presented at three distances (60, 120 & 240 cm). In between testing sessions participants performed tool-use training and either used physical or virtual tools to manipulate objects at distances between 120 and 200 cm. For young participants, prior to training the reproduced intervals were significantly longer for stimuli at an intermediate distance (120cm) compared to near the body (60cm), though this effect was not observed for the elderly. For young participants, tool-use training significantly shortened the reproduced intervals for stimuli at 120 cm, hence the distance at which tool-use training was operated. This effect was again absent in the elderly, resulting in a significant group-difference. In both groups, participants' sensitivity to the presented intervals did not differ between distances prior to training, but was significantly reduced by tool-use training systematically at all distances. We observed qualitatively similar results for experiments in physical and virtual setups but the effect sizes were generally small, pointing to systematic but weak effects. Overall, this supports previous claims that time perception is tied to space and our interaction with this when we are young, though further work is required to understand the robustness and specificity of these effects. Keywords: Time perception, Peripersonal Space, Space Representation, Active Tool-use, Aging