The neural substrates of subjective time dilation

Marc Wittmann

doi:10.3389/neuro.09.002.2010

Abstract

An object moving towards an observer is subjectively perceived as longer in duration than the same object that is static or moving away. This ”time dilation effect” has been shown for a number of stimuli that differ from standard events along different feature dimensions (e.g. color, size, and dynamics). We performed an event-related functional magnetic resonance imaging (fMRI) study, while subjects viewed a stream of five visual events, all of which were static and of identical duration except the fourth one, which was a deviant target consisting of either a looming or a receding disc. The duration of the target was systematically varied and participants judged whether the target was shorter or longer than all other events. A time dilation effect was observed only for looming targets. Relative to the static standards, the looming as well as the receding targets induced increased activation of the anterior insula and anterior cingulate cortices (the ”core control network”). The decisive contrast between looming and receding targets representing the time dilation effect showed strong asymmetric activation and, specifically, activation of cortical midline structures (the ”default network”). These results provide the first evidence that the illusion of temporal dilation is due to activation of areas that are important for cognitive control and subjective awareness. The involvement of midline structures in the temporal dilation illusion is interpreted as evidence that time perception is related to self-referential processing.

Highlights

The neural mechanisms mediating the subjective perception of time are currently debated (Eagleman et al, 2005; Wittmann and van Wassenhove, 2009)
On average, a steady target of 527 ms, a looming target of 419 ms and a receding target of 502 ms were all perceived as having the same duration as a standard event of 500 ms
Additional paired t-tests showed a significant effect of condition in the longer duration range when comparing LOOM and STEADY [t(1,15) = −7.948, P < 0.0001] and RECEDE and STEADY [t(1,15) = −5.550, P < 0.0001]

Summary

Introduction

The neural mechanisms mediating the subjective perception of time are currently debated (Eagleman et al, 2005; Wittmann and van Wassenhove, 2009). Of particular relevance here, looming signals (expanding discs) are associated with subjective time dilation whereas receding signals (shrinking discs) do not result in an altered experience of time (van Wassenhove et al, 2008). These findings converge with the observations that looming signals are salient events (Yantis and Egeth, 1999) and are more powerful in drawing attention compared to other stimuli (Franconeri et al, 2005). If self-referential processing is related to time perception, the looming signals should provoke relative overestimation of duration

Methods

Results

Conclusion