Life motion signals lengthen perceived temporal duration

Abstract

Point-light biological motions, conveying various different attributes of biological entities, have particular spatiotemporal properties that enable them to be processed with remarkable efficiency in the human visual system. Here we demonstrate that such signals automatically lengthen their perceived temporal duration independent of global configuration and without observers' subjective awareness of their biological nature. By using a duration discrimination paradigm, we showed that an upright biological motion sequence was perceived significantly longer than an inverted but otherwise identical sequence of the same duration. Furthermore, this temporal dilation effect could be extended to spatially scrambled biological motion signals, whose global configurations were completely disrupted, regardless of whether observers were aware of the nature of the stimuli. However, such an effect completely disappeared when critical biological characteristics were removed. Taken together, our findings suggest a special mechanism of time perception tuned to life motion signals and shed new light on the temporal encoding of biological motion.point-light walker | temporal expansion | psychometric function O ur senses not only enable our brain to perceive images and sounds, but they also inform us about the passage of time. Time perception over fine scales is fundamental to a range of everyday human activities (for example, to estimate how fast you need to run to catch a ball), and we seem to be able to accurately estimate time as if there exists a specific mechanism that can measure time (e.g., an internal clock; refs. 1, 2). Although it seems quite natural, perceiving time is an extremely complex phenomenon that involves a number of unresolved issues in psychology, and we are far from completely understanding its underlying mechanisms. It has been shown that there is not a specific sensory organ designed to tell time and our representations of subjective temporal duration vary in response to variations of external sensory inputs (reviewed in ref.3).Stimulus motion is thought of as a crucial property that can modulate and alter our perception of time. Several studies have shown that a moving stimulus is perceived to last longer in duration than a slower or stationary stimulus of the same physical duration, a phenomenon referred to as subjective time dilation (4-9). Some researchers proposed that this subjective time dilation effect might reflect a result of long-term evolutionary adaptation (6, 10). By lengthening the subjective duration of those moving and important stimuli and thus enhancing their temporal resolution, observers may be able to process such signals in greater depth per unit of objective time (11), which potentially provides an ecological advantage allowing living organisms to anticipate events or actions and to better adapt themselves to the environment (6). Although the underlying mechanism of the time distortion induced by motion has often been speculated from a point of evolutionary view, all these studies us...

Effects of speeding up or slowing down animate or inanimate motions on timing

“…Consistent with this hypothesis, there is recent evidence that time perception and motor timing are influenced by animacy: The observation of a biological movement performed by other people may bias the timing of a motor act or the judgement of perceived duration of an event (Watanabe 2008;Bove et al 2009;Carrozzo et al 2010;Zago et al 2011b;Mouta et al 2012;Wang and Jiang 2012). In particular, Carrozzo et al (2010) investigated two different timing tasks: (1) button-press responses aimed at intercepting a falling ball and (2) discrimination of the duration of a stationary flash.…”

“…According to one hypothesis, the time base used by the brain to process visual motion is calibrated against the predictions regarding the motion of biological characters when animacy is detected by the observer, while the time base is calibrated against the predictions of motion of passive objects when no animacy is detected (Chang and Troje 2008;Sebanz and Knoblich 2009;Carrozzo et al 2010;Zago et al 2011a, b;Wang and Jiang 2012).…”

Time, Emotion and the Embodiment of Timing

“…For instance, Wittmann, van Wassenhove, Craig & Paulus (2010a) showed that an object moving towards an observer was perceived as longer in duration than the same object that was static or moving away. Wang & Yi Jiang (2012) also observed a subjective temporal dilation in a bisection task when participants were presented with a motion sequence of point-light walker compared to a non-biological motion or a static picture with the same amount of point lights. However, further investigations are also needed to understand the influence of the temporal memories activated during time judgments for body posture pictures.…”

Moving time: The influence of action on duration perception.

“…For example, perceived motion of upright point light walkers is temporally dilated relative to inverted walkers (Wang & Jiang, 2012; see also Gavazzi, Bisio, & Pozzo, 2013). In the present experiments, we examine how movement influences the perceived duration of sensory outcomes of action.…”