Perceptual content, not physiological signals, determines perceived duration when viewing dynamic, natural scenes

Abstract

The neural basis of time perception remains unknown. A prominent account is the pacemaker-accumulator model, wherein regular ticks of some physiological or neural pacemaker are read out as time. Putative candidates for the pacemaker have been suggested in physiological processes (heartbeat), or dopaminergic mid-brain neurons, whose activity has been associated with spontaneous blinking. However, such proposals have difficulty accounting for observations that time perception varies systematically with perceptual content. We examined physiological influences on human duration estimates for naturalistic videos between 1-64 seconds using cardiac and eye recordings. Duration estimates were biased by the amount of change in scene content. Contrary to previous claims, heart rate, and blinking were not related to duration estimates. Our results support a recent proposal that tracking change in perceptual classification networks provides a basis for human time perception, and suggest that previous assertions of the importance of physiological factors should be tempered.

Trial-by-trial predictions of subjective time from human brain activity

“…Our results were robust under a wide range of model parameter values (Fig. 1C-E, right), and, in combination with results from the perceptual classification network model and previous findings (10,28), supports the idea that human time perception is based in the neural processes associated with processing the sensory context in which time is being judged.…”

A predictive processing model of episodic memory and time perception

“…First, regardless of task and load, the degree of duration overestimation was reduced particularly for the Office and cafe scenes (for City scenes mean duration judgement ratio is 1.327 ± 0.867, for Campus & outside scenes: 1.313 ± 0.832 and for Office & cafe scenes: 1.124 ± 0.735 were the overall means and standard deviations respectively). This pattern broadly replicates that seen in the previously reported results for different experiments using these same stimuli 4,12 . Of greater interest, the nature of the task-by-load interaction also qualitatively changes with scene type.…”

“…It was recently demonstrated 4 that tracking salient events in the activity of an artificial image classification network while it processed videos of natural scenes (from 1-64 seconds in duration) can provide a basis for estimates of duration. In that study, model-based estimates replicated key features of human duration estimates of the exact same videos, including biases related to scene type (busy city scenes estimated as longer that quiet office scenes, for example; see also 12,13 ). The model displayed conceptual similarities with the predictive processing account of perception wherein perception is proposed to operate as a function of both sensory predictions and current sensory stimulation, with perceptual content understood as the brain's "best guess" (Bayesian posterior) of the causes of current sensory input given the prior expectations or predictions [14][15][16][17][18] .…”

“…Reassuringly, the previously reported task-by-cognitive load interaction 7 is apparent in our data (compare Figure 1 and Figure 5B), though in our data it is of a smaller magnitude and is shifted towards overestimation rather than underestimation. This shift towards overestimation was likely due to our experiment using more dynamic stimuli which are known to result in longer duration estimates 4,12,42 (see also Figure 5C). Furthermore, the task-by-load interaction in our data becomes less straightforward when broken down by the different scene types that were used as stimuli (City, campus and outside, and office/cafe) ( Figure 5C).…”

“…We used the online platform Amazon Mechanical Turk (MTurk) to recruit 12,827 participants. Each participant watched a single video (1 -64 seconds in duration) of a natural scene such as walking around a city, walking in the countryside or a leafy campus, or in a quiet office or a cafe (the same video stimuli were also used in 4,12 ; in these previous studies, each participant viewed a large number of videos) and reported the duration in seconds (see Figure 9). Half the participants were not informed that they would need to estimate the video duration until after they had viewed it (retrospective task group) while half were told before the trial began (prospective group).…”