Visual Duration but Not Numerosity Is Distorted While Running

There is increasing evidence that action and perception interact in the processing of magnitudes such as duration and numerosity. Sustained physical exercise (such as running or cycling) increases the apparent duration of visual stimuli presented during the activity. However, the effect of exercise on numerosity perception has not yet been investigated. Here, we asked participants to make either a temporal or a numerical judgment by comparing the duration or numerosity of standard stimuli displayed at rest with those presented while running. The results support previous reports in showing that physical activity significantly expands perceived duration; however, it had no effect on perceived numerosity. Furthermore, the distortions of the perceived durations vanished soon after the running session, making it unlikely that physiological factors such as heart rate underlie the temporal distortion. Taken together, these results suggest a domain-selective influence of the motor system on the perception of time, rather than a general effect on magnitude.

The Topographic Representation of Time and its Link With Temporal Context and Perception

Neuronal tuning and topography are mechanisms widely used in the brain to represent sensory information and also abstract features like time. In humans, temporal topography has been shown in a wide circuit of brain regions. However, it is unclear whether chronotopic maps are specific to vision, whether they map time in an absolute or relative fashion, to what extent they reflect objective or subjective time and whether they are influenced by temporal context. Here we asked human participants to reproduce the durations of sounds in two, partially overlapping, temporal contexts while we record high-spatial resolution fMRI. Both model-based and data driven analyses show the presence of auditory chronomaps in the auditory parabelt, intraparietal sulcus, and in supplementary motor area. Most importantly, when the same physical duration is presented in different temporal contexts, and thus perceived differently, different neuronal units respond to it. Those units are also spatially shifted according to the relative position of the perceived duration within each context. Finally, the pattern of activity is more similar within rather than across contexts suggesting their pivotal role in shaping the maps. These results highlight two important properties of chronomaps: their flexibility of representation and their dependency on the context.

Weighted Integration of Duration Information Across Visual and Auditory Modality Is Influenced by Modality-Specific Attention

We constantly integrate multiple types of information from different sensory modalities. Generally, such integration is influenced by the modality that we attend to. However, for duration perception, it has been shown that when duration information from visual and auditory modalities is integrated, the perceived duration of the visual stimulus leaned toward the duration of the auditory stimulus, irrespective of which modality was attended. In these studies, auditory dominance was assessed using visual and auditory stimuli with different durations whose timing of onset and offset would affect perception. In the present study, we aimed to investigate the effect of attention on duration integration using visual and auditory stimuli of the same duration. Since the duration of a visual flicker and auditory flutter tends to be perceived as longer than and shorter than its physical duration, respectively, we used the 10 Hz visual flicker and auditory flutter with the same onset and offset timings but different perceived durations. The participants were asked to attend either visual, auditory, or both modalities. Contrary to the attention-independent auditory dominance reported in previous studies, we found that the perceived duration of the simultaneous flicker and flutter presentation depended on which modality the participants attended. To further investigate the process of duration integration of the two modalities, we applied Bayesian hierarchical modeling, which enabled us to define a flexible model in which the multisensory duration is represented by the weighted average of each sensory modality. In addition, to examine whether auditory dominance results from the higher reliability of auditory stimuli, we applied another models to consider the stimulus reliability. These behavioral and modeling results suggest the following: (1) the perceived duration of visual and auditory stimuli is influenced by which modality the participants attended to when we control for the confounding effect of onset–offset timing of stimuli, and (2) the increase of the weight by attention affects the duration integration, even when the effect of stimulus reliability is controlled. Our models can be extended to investigate the neural basis and effects of other sensory modalities in duration integration.

Anticipation of aversive visual stimuli lengthens perceived temporal duration

Subjective estimates of elapsed time are sensitive to the fluctuations in an emotional state. While it is well known that dangerous and threatening situations, such as electric shocks or loud noises, are perceived as lasting longer than safe events, it remains unclear whether anticipating a threatening event speeds up or slows down subjective time and what defines the direction of the distortion. We examined whether the anticipation of uncertain visual aversive events resulted in either underestimation or overestimation of perceived duration. The participants did a temporal bisection task, where they estimated durations of visual cues relative to previously learnt long and short standard durations. The colour of the to-be-timed visual cue signalled either a 50% or 0% probability of encountering an aversive image at the end of the interval. The cue durations were found to be overestimated due to anticipation of aversive images, even when no image was shown afterwards. Moreover, the overestimation was more pronounced in people who reported feeling more anxious while anticipating the image. These results demonstrate that anxiogenic anticipation of uncertain visual threats induce temporal overestimation, which questions a recently proposed view that temporal underestimation evoked by uncertain threats is due to anxiety.

The Topographic Representation of Time and its Link with Temporal Context and Perception

Neuronal tuning and topography are mechanisms widely used in the brain to represent not only sensory information but also abstract features like numerosity and time. In humans, temporal topography has been shown recently in a wide circuit of brain regions, from lateral occipital to inferior parietal and premotor regions. However, it remains unclear whether chronotopic maps are specific to vision, whether they map time in an absolute or relative fashion, and to what extent they reflect objective or subjective, perceived time and whether they are influenced by temporal context. Here we asked human participants to reproduce the durations of sounds in two, partially overlapping, temporal contexts while we recorded high-spatial resolution fMRI. Both model-based and data driven analysis approaches show the presence of auditory chronomaps in the auditory parabelt, intraparietal sulcus, and in the supplementary motor area (SMA). Most importantly, when the same physical duration is presented in different temporal contexts, and thus perceived differently, different neuronal units respond to it. Those units were also spatially shifted on the cortical surface according to the relative position of the perceived duration within each context. Finally, voxels did not change their preferences across contexts and their pattern of activity was more similar within rather than across them, suggesting a pivotal role of the context in shaping the maps. These results highlight two important properties of human chronomaps: their flexibility of representation due to perception and their dependency on temporal context.

Simulating drone and bodily gestures: a behavioral study

According to embodied simulation theory, humans tacitly ‘simulate’ the actions of the other by mapping them in the sensorimotor cortex of the brain. According to the framework of embodied cinema, the meaning-making process in film is considered to be inextricably linked to the interrelation between the brain, body and environment of the viewer. Athough there are a growing number of theoretical and technological studies on the embodied nature of drone flight, to date no studies have investigated the effect of drone footage with and without human bodily movement on spectators’ cognitive behavioral mechanisms. Thus, the present study investigates the relationship between Drone Movement (Ascending, Descending, Still) , Actor Presence (Female, Male, None) and Image Speed (Normal, Slow, Very Slow) on perceived motion, appeal and involvement measures. To achieve these aims, a custom-made, naturalistic set of video stimuli modeled after the staircase scene in the Soviet film The Cranes Are Flying (Kalatozov, 1957) was created using a DJI Phantom Pro 4 Drone. In the experimental task (carried out at the computer), participants were asked to rate video stimuli using a Visual Analogue Scale (VAS) ranging from 0 to 100 for perceived Duration, Liking, Movement, and Emotional and Physical Involvement. Results demonstrate that: 1) Ascending and Descending had significantly higher ratings for perceived Duration, Movement and Physical and Emotional Involvement than Still; 2) Ascending had significantly higher ratings for perceived Duration, Movement and Emotional Involvement than Descending; 3) Female and Male had significantly higher ratings for Movement, Physical Involvement and Emotional Involvement than None (No Actor); 4) Normal Image Speed had significantly higher ratings for Movement, Physical Involvement and Emotional Involvement with respect to Slow and Very Slow. Results indicate that drone/actor ascent may evoke more motion and involvement due to perceived exertion or ‘effort’ to climb up the stairs, and that participants resonate more with conspecifics and familiar repertoires, in support of embodied simulation theory. Results also indicate that movement in the drone/actor image modulates perceived time. Neuroimaging studies are needed to investiate the impact of drone movement with or without human bodily movement on cortical sensorimotor activation in the brain.

Filled-Duration Illusions

Data relevant to the ‘filled-duration illusion’, the claim that filled intervals appear to last longer than unfilled ones of the same real duration, are reviewed. A distinction is made between divided-time studies (where an empty interval has one or more than one brief dividing stimulus inside it) and filled-duration studies (where the filled intervals are filled with some continuous event). Divided durations appear to last longer than empty ones, and the effect grows with the number of dividers, although it may be restricted to short durations. The best current explanation appears to involve the weighted summation of the different subintervals of which the total duration is composed. When intervals with simple fillers are contrasted with empty ones, they are usually judged as longer, and the effect may grow as the intervals lengthen, at least over short duration ranges. When complex fillers are used, fillers usually have no effect on perceived duration or shorten it. A pacemaker-counter approach can account for some simple filler effects, and division of attention for complex filler effects. Although there are some exceptions, ‘filled-interval illusions’ of all these types are normally found, but some problems, such as questions about the relative perceived variability of filled and unfilled intervals, or stimulus order effects, merit further research.