Tempo Rubato : Animacy Speeds Up Time in the Brain

Abstract

BackgroundHow do we estimate time when watching an action? The idea that events are timed by a centralized clock has recently been called into question in favour of distributed, specialized mechanisms. Here we provide evidence for a critical specialization: animate and inanimate events are separately timed by humans.Methodology/Principal FindingsIn different experiments, observers were asked to intercept a moving target or to discriminate the duration of a stationary flash while viewing different scenes. Time estimates were systematically shorter in the sessions involving human characters moving in the scene than in those involving inanimate moving characters. Remarkably, the animate/inanimate context also affected randomly intermingled trials which always depicted the same still character.Conclusions/SignificanceThe existence of distinct time bases for animate and inanimate events might be related to the partial segregation of the neural networks processing these two categories of objects, and could enhance our ability to predict critically timed actions.

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

“…In all cases, the background characters and their movements were totally unrelated to the foreground target and to the viewer's action. Carrozzo et al (2010) found that, for both the motor interception and the time discrimination task, the time estimates were systematically shorter in the sessions involving human characters moving in the background than in those involving inanimate moving characters. The presence of a systematic offset between the time estimates associated with biological movements and the time estimates associated with nonbiological movements is compatible with the hypothesis that there exist timing mechanisms differentially tuned to biological movements and to non-biological movements.…”

“…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).…”

“…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. They used interference paradigms in which the timing task was run concurrently with the presentation of different computer-graphics characters in the background of the scene.…”

“…In Experiment 1, we used the same interception task and two types of background characters included in Carrozzo et al (2010). The animate character was a dancer, while the inanimate character was a whirligig consisting of 14 disconnected rods whose motion matched that of the corresponding body segments of the dancer.…”