Chronostasis without voluntary action

In a previous study we explored auditory chronostasis and suggested an arousal account of this temporal illusion rather than one dependent on backdating actions to the onset of a motor event. Here we present three experiments designed to distinguish between two competing accounts of the mechanisms underlying the illusion. Experiment 1 investigated whether voluntary movements are necessary for the illusion to occur. Experiment 2 sought to clarify whether auditory chronostasis occurs when the intervals to be judged are continuous (temporally contiguous) rather than separate events. Experiment 3 was designed to establish whether increased task demands account for the illusion. Together the results from these experiments show that chronostasis is an illusion that is not dependent on voluntary action, can occur without a change in the spatial location of the stimulus (thus precluding an account based on spatial attention), occurs with discrete as well as continuous events, and is affected by the salience of the termination of the event to be timed rather than the onset. Collectively these findings suggest that the mechanisms underlying chronostasis are best explained by an arousal hypothesis since neither attention nor backdating to action can account for the commonalities between chronostasis in the auditory, visual and tactile domains.