236 research outputs found

    Time Changes with the Embodiment of Another’s Body Posture

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    The aim of the present study was to investigate whether the perception of presentation durations of pictures of different body postures was distorted as function of the embodied movement that originally produced these postures. Participants were presented with two pictures, one with a low-arousal body posture judged to require no movement and the other with a high-arousal body posture judged to require considerable movement. In a temporal bisection task with two ranges of standard durations (0.4/1.6 s and 2/8 s), the participants had to judge whether the presentation duration of each of the pictures was more similar to the short or to the long standard duration. The results showed that the duration was judged longer for the posture requiring more movement than for the posture requiring less movement. However the magnitude of this overestimation was relatively greater for the range of short durations than for that of longer durations. Further analyses suggest that this lengthening effect was mediated by an arousal effect of limited duration on the speed of the internal clock system

    Distortions of Subjective Time Perception Within and Across Senses

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    Background: The ability to estimate the passage of time is of fundamental importance for perceptual and cognitive processes. One experience of time is the perception of duration, which is not isomorphic to physical duration and can be distorted by a number of factors. Yet, the critical features generating these perceptual shifts in subjective duration are not understood. Methodology/Findings: We used prospective duration judgments within and across sensory modalities to examine the effect of stimulus predictability and feature change on the perception of duration. First, we found robust distortions of perceived duration in auditory, visual and auditory-visual presentations despite the predictability of the feature changes in the stimuli. For example, a looming disc embedded in a series of steady discs led to time dilation, whereas a steady disc embedded in a series of looming discs led to time compression. Second, we addressed whether visual (auditory) inputs could alter the perception of duration of auditory (visual) inputs. When participants were presented with incongruent audio-visual stimuli, the perceived duration of auditory events could be shortened or lengthened by the presence of conflicting visual information; however, the perceived duration of visual events was seldom distorted by the presence of auditory information and was never perceived shorter than their actual durations. Conclusions/Significance: These results support the existence of multisensory interactions in the perception of duration and, importantly, suggest that vision can modify auditory temporal perception in a pure timing task. Insofar as distortions in subjective duration can neither be accounted for by the unpredictability of an auditory, visual or auditory-visual event, we propose that it is the intrinsic features of the stimulus that critically affect subjective time distortions

    An Integrated-Photonics Optical-Frequency Synthesizer

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    Integrated-photonics microchips now enable a range of advanced functionalities for high-coherence applications such as data transmission, highly optimized physical sensors, and harnessing quantum states, but with cost, efficiency, and portability much beyond tabletop experiments. Through high-volume semiconductor processing built around advanced materials there exists an opportunity for integrated devices to impact applications cutting across disciplines of basic science and technology. Here we show how to synthesize the absolute frequency of a lightwave signal, using integrated photonics to implement lasers, system interconnects, and nonlinear frequency comb generation. The laser frequency output of our synthesizer is programmed by a microwave clock across 4 THz near 1550 nm with 1 Hz resolution and traceability to the SI second. This is accomplished with a heterogeneously integrated III/V-Si tunable laser, which is guided by dual dissipative-Kerr-soliton frequency combs fabricated on silicon chips. Through out-of-loop measurements of the phase-coherent, microwave-to-optical link, we verify that the fractional-frequency instability of the integrated photonics synthesizer matches the 7.010137.0*10^{-13} reference-clock instability for a 1 second acquisition, and constrain any synthesis error to 7.710157.7*10^{-15} while stepping the synthesizer across the telecommunication C band. Any application of an optical frequency source would be enabled by the precision optical synthesis presented here. Building on the ubiquitous capability in the microwave domain, our results demonstrate a first path to synthesis with integrated photonics, leveraging low-cost, low-power, and compact features that will be critical for its widespread use.Comment: 10 pages, 6 figure

    Temporal Accumulation and Decision Processes in the Duration Bisection Task Revealed by Contingent Negative Variation

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    The duration bisection paradigm is a classic task used to examine how humans and other animals perceive time. Typically, participants first learn short and long anchor durations and are subsequently asked to classify probe durations as closer to the short or long anchor duration. However, the specific representations of time and the decision rules applied in this task remain the subject of debate. For example, researchers have questioned whether participants actually use representations of the short and long anchor durations in the decision process rather than merely a response threshold that is derived from those anchor durations. Electroencephalographic (EEG) measures, like the contingent negative variation (CNV), can provide information about the perceptual and cognitive processes that occur between the onset of the timing stimulus and the motor response. The CNV has been implicated as an electrophysiological marker of interval timing processes such as temporal accumulation, representation of the target duration, and the decision that the target duration has been attained. We used the CNV to investigate which durations are involved in the bisection categorization decision. The CNV increased in amplitude up to the value of the short anchor, remained at a constant level until about the geometric mean (GM) of the short and long anchors, and then began to resolve. These results suggest that the short anchor and the GM of the short and long anchors are critical target durations used in the bisection categorization decision process. In addition, larger mean N1P2 amplitude differences were associated with larger amplitude CNVs, which may reflect the participant’s precision in initiating timing on each trial across a test session. Overall, the results demonstrate the value of using scalp-recorded EEG to address basic questions about interval timing

    Increased temporal sensitivity for threat: A Bayesian generalized linear mixed modeling approach.

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    People overestimate the duration of threat-related facial expressions, and this effect increases with self-reported fearfulness (Tipples in Emotion, 8, 127-131, 2008, Emotion, 11, 74-80, 2011). One explanation (Cheng, Tipples, Narayanan, & Meck in Timing and Time Perception, 4, 99-122, 2016) for this effect is that emotion increases the rate at which temporal information accumulates. Here I tested whether increased overestimation for threat-related facial expressions in high fearfulness generalizes to pictures of threatening animals. A further goal was to illustrate the use of Bayesian generalized linear mixed modeling (GLMM) to gain more accurate estimates of temporal performance, including estimates of temporal sensitivity. Participants (N = 53) completed a temporal bisection task in which they judged the presentation duration for pictures of threatening animals (poised to attack) and nonthreatening animals. People overestimated the duration of threatening animals, and the effect increased with self-reported fearfulness. In support of increased accumulation of pacemaker ticks due to threat, temporal sensitivity was higher for threat than for nonthreat images. Analyses indicated that temporal sensitivity effects may have been absent in previous research because of the method used to calculate the index of temporal sensitivity. The benefits of using Bayesian GLMM are highlighted, and researchers are encouraged to use this method as the first option for analyzing temporal bisection data

    The potential of a mobile group blog to support cultural learning among overseas students

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    We explored the use of mobile social software, in the form of a mobile group blog, to assist cultural learning. The potential of using this technology for cultural adaptation among overseas students was examined as those students adapted to the everyday life of studying abroad. Two pilot studies and a successful field study of a mobile group blog as used by UK overseas students are reported. A further study with prospective overseas students witnessing this ‘moblogging’ in China revealed the advantages of communicating through this technology as a form of peer-supported preparation for cultural adaptation. Potential advantages for learning a second language via this system, were highlighted as communication was interweaved with cultural adaptation and exercised in the blog entries. Given mobile internet, the language experience together with cultural observation impressively supported these students' growing confidence with time, space and imagination

    The interaction of gambling outcome and gambling harm-minimisation strategies for electronic gambling: the efficacy of computer generated self-appraisal messaging

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    It has been argued that generating pop-up messages during electronic gambling sessions, which cause a player to engage in self-appraisal of their gambling behaviour, instil greater control and awareness of behaviour (Monaghan, Computers in Human Behaviour, 25, 202–207, 2009). Consideration for the potential interaction between the messaging’s efficacy and gambling outcome (winning or losing) is lacking however. Thirty participants took part in a repeated-measures experiment where they gambled on the outcome of a computer-simulated gambling task. Outcome was manipulated by the experimenter to induce winning and losing streaks. Participants gambled at a significantly faster speed and a higher average stake size, which resulted in a greater betting intensity in the Loss condition compared to the Win condition. Computer generated self-appraisal messaging was then applied during the gambling session, which was able to significantly reduce the average speed of betting in the Loss condition only, demonstrating an interaction effect between computer generated messaging and gambling outcome
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