The heart beat does not make us tick: The impacts of heart rate and arousal on time perception

According to popular models of human time perception, variations in prospective timing are caused by two factors: the pulse rate of an internal pacemaker and the amount of attention directed to the passage of time. The results concerning the effect of attention on subjective timing have been conclusive, but the mechanisms that drive the pacemaker are still far from being understood. In two experiments, we examined the impact of two factors that in the existing literature on human time perception have been argued to affect such a pacemaker: arousal and heart rate. Experienced arousal and heart rate were varied independently by means of specific physical exercises: (a) A muscle exercise increased arousal and heart rate; (b) a breath-holding exercise increased arousal but decreased heart rate; and (c) in the control condition, arousal and heart rate were held constant. The results indicate that increased subjective arousal leads to higher time estimates, whereas heart rate itself has no relevant impact on time perception. The results are discussed with respect to the underlying mechanisms of prospective time perception.     

Offline improvement occurs for temporal stability but not accuracy following practice of integer and non-integer rhythms

Procedural learning benefits from memory processes occurring outside practice resulting in offline learning. Offline gains have been demonstrated almost exclusively for the ordinal structure of sequential motor tasks. Many skills also demand that the correct serial order of events be appropriately timed. Evidence indicates that the temporal aspect of a procedural skill can be encoded independent of serial order knowledge and governed by at least two distinct neural circuits. The present experiment determined if (a) offline gains emerge for temporal learning, and (b) if such gains occur for timing supervised by distinct timing systems. Participants experienced 216 practice trials of a 7-key press sequence that involved integer- or non-integer timing rhythms. Twenty-four hours after training 30 test trials were administered. Results revealed robust offline enhancement for timing performance of the non-integer based temporal sequences. This improvement was localized to stabilization of the required relative but not absolute time profiles. The neural circuitry central to supporting the performance of non-integer timing sequences is also a principal constituent of what is described as the "cognitive" timing system. Timing governed by this system appears most susceptible to offline gains via consolidation.     

Why 'Sounds Are Judged Longer Than Lights': Application of a Model of the Internal Clock in Humans

Three experiments, using temporal generalization and verbal estimation methods, studied judgements of duration of auditory (500-Hz tone) and visual (14-cm blue square) stimuli. With both methods, auditory stimuli were judged longer, and less variable, than visual ones. The verbal estimation experiments used stimuli from 77 to 1183 msec in length, and the slope of the function relating mean estimate to real length differed between modalities (but the intercept did not), consistent with the idea that a pacemaker generating duration representations ran faster for auditory than for visual stimuli. The different variability of auditory and visual stimuli was attributed to differential variability in the operation of a switch of a pacemaker-accumulator clock, and experimental datasuggested that such switch effects were separable from changes in pacemaker speed. Overall, the work showed how a clock model consistent with scalar timing theory, the leading account of animal timing, can address an issue derived from the classical literature on human time perception.     

The behavioral theory of timing: Reinforcer rate determines pacemaker rate

In the behavioral theory of timing, pulses from a hypothetical Poisson pacemaker produce transitions between states that are correlated with adjunctive behavior. The adjunctive behavior serves as a discriminative stimulus for temporal discriminations. The present experiments tested the assumption that the average interpulse time of the pacemaker is proportional to interreinforcer interval. Responses on a left key were reinforced at variable intervals for the first 25 s since the beginning of a 50-s trial, and right-key responses were reinforced at variable intervals during the second 25 s. Psychometric functions relating proportion of right-key responses to time since trial onset, in 5-s intervals across the 50-s trial, were sigmoidal in form. Average interpulse times derived by fitting quantitative predictions from the behavioral theory of timing to obtained psychometric functions decreased when the interreinforcer interval was decreased and increased when the interreinforcer interval was increased, as predicted by the theory. In a second experiment, average interpulse times estimated from trials without reinforcement followed global changes in interreinforcer interval, as predicted by the theory. Changes in temporal discrimination as a function of interreinforcer interval were therefore not influenced by the discrimination of reinforcer occurrence. The present data support the assumption of the behavioral theory of timing that interpulse time is determined by interreinforcer interval.     

Analysis of timing variability in human movements by aligning parameter curves in time

The analysis of timing in human movements requires a reference with which timing can be quantified. In reactive movements this reference is given by the stimulus. However, many movements do not respond to such an external event. In throwing, for instance, the hand opening for release has to be timed to an acceleration of the throwing arm. A common approach to analyzing release-timing variability is to choose a landmark in the movement that is supposed to have a fixed temporal relation to the release. Such distinct landmarks, however, are not always well definable. Therefore, the present article describes an alternative approach analyzing timing variability on the basis of the alignment of different trials relative to their kinematic shape, by shifting the trials in the time domain. The basic assumption behind this approach is that single throwing movements are one instance of an acquired movement template, and thus show a considerable similarity. In contrast, the location of the temporal moment of release varies from trial to trial, generating imprecision regarding the release timing. In trials synchronized with respect to the release, this variability can be assessed by shifting the kinematic profiles of the throwing movements in time such that they superimpose as closely as possible. As a result, the corresponding time shifts for all trials represent a measure of the release time deviations across trials, and the standard deviation of these deviations represents the timing variability. Aside from timing analyses in such movements as throwing, the approach can be applied to very different tasks with timing demands—for example, to neurophysiological signals.     

Differences in duration discrimination of filled and empty auditory intervals as a function of base duration

In the present experiments, participants were presented with two time intervals that were marked by auditory signals, and their task was to decide which of the two was longer in duration. In Experiment 1, the base durations were 50 and 1,000msec, whereas in Experiment 2, seven different base durations ranging from 50 to 1,000 msec were employed. It was found that filled intervals (continuous tones) were discriminated more accurately than empty intervals (with onset and offset marked by clicks) at the 50-msec base duration, whereas no performance differences could be shown for longer ones. The findings are consistent with the notion of a unitary timing mechanism that governs the timing of both filled and empty auditory intervals, independent of base durations. A likely conceptual framework that could explain better performance with filled as compared with empty intervals represents an information-processing model of interval timing that evolved from scalar timing theory. According to this account, a performance decrement observed with empty intervals may be due to a misassignment of pulses generated by an internal pacemaker.     

A tuned-trace theory of interval-timing dynamics

Animals on interval schedules of reinforcement can rapidly adjust a temporal dependent variable, such as wait time, to changes in the prevailing interreinforcement interval. We describe data on the effects of impulse, step, sine-cyclic, and variable-interval schedules and show that they can be explained by a tuned-trace timing model with a one-back threshold-setting rule. The model can also explain steady-state timing properties such as proportional and Weber law timing and the effects of reinforcement magnitude. The model assumes that food reinforcers and other time markers have a decaying effect (trace) with properties that can be derived from the rate-sensitive property of habituation (the multiple-time-scale model). In timing experiments, response threshold is determined by the trace value at the time of the most recent reinforcement. The model provides a partial account for the learning of multiple intervals, but does not account for scalloping and other postpause features of responding on interval schedules and has some problems with square-wave schedules.     

时间分层加工研究述评

为了探讨数秒内不同层级时间加工的特性,研究者分别从“时间信息加工”和“信息加工的计时特性”角度开展了一系列研究。Münsterberg (1889)、Michon(1985) 、Lewis 和 Miall(2003) 及Vierodt(1868)从前一角度,分别指出1/3秒、1/2秒、1秒及3秒可能是数秒以内时距加工机制的分界点,分界点以下与以上的加工机制存在差异。P?ppel(1997, 2009)则从后一角度指出限制信息加工过程的两类时间窗,一类时间窗是以20-60毫秒振荡周期运行的高频系统,属于初级整合单元;另一类时间窗主要是处理2-3秒以内事件系列的低频系统,属于高级整合单元。前一类时间窗可以为信息加工整合基本的心理事件,后一类时间窗则是把2-3秒内的心理事件整合为基本知觉单元。基于以往研究的剖析,我们认为1/3秒、1/2秒及1秒等分界点的真伪性尚需进一步验证,并进一步假设40毫秒以内时间不能觉察为时距;40毫秒至3秒之间,随着长度增加,自动化加工减弱,控制性加工增强;3秒以上主要为控制性加工,涉及记忆过程。     

Timing the “magical number seven”: Presentation rate and regularity affect verbal working memory performance

The informative value of time and temporal structure often remains neglected in cognitive assessments. However, next to information about stimulus identity we can exploit temporal ordering principles, such as regularity, periodicity, or grouping to generate predictions about the timing of future events. Such predictions may improve cognitive performance by optimising adaptation to dynamic stimuli. Here, we investigated the influence of temporal structure on verbal working memory by assessing immediate recall performance for aurally presented digit sequences (forward digit span) as a function of standard (1000 ms stimulus-onset-asynchronies, SOAs), short (700 ms), long (1300 ms) and mixed (700–1300 ms) stimulus timing during the presentation phase. Participant's digit spans were lower for short and mixed SOA presentation relative to standard SOAs. This confirms an impact of temporal structure on the classic “magical number seven,” suggesting that working memory performance can in part be regulated through the systematic application of temporal ordering principles.     

Perception of Happening: How the Brain Deals with the No-History Problem

In physics, the temporal dimension has units of infinitesimally brief duration. Given this, how is it possible to perceive things, such as motion, music, and vibrotactile stimulation, that involve extension across many units of time? To address this problem, it is proposed that there is what is termed an “information construct of happening” (ICOH), a simultaneous representation of recent, temporally differentiated perceptual information on the millisecond time scale. The main features of the ICOH are (i) time marking, semantic labeling of all information in the ICOH with ordinal temporal information and distance from what is informationally identified as the present moment, (ii) vector informational features that specify kind, direction, and rate of change for every feature in a percept, and (iii) connectives, information relating vector informational features at adjacent temporal locations in the ICOH. The ICOH integrates products of perceptual processing with recent historical information in sensory memory on the subsecond time scale. Perceptual information about happening in informational sensory memory is encoded in semantic form that preserves connected semantic trails of vector and timing information. The basic properties of the ICOH must be supported by a general and widespread timing mechanism that generates ordinal and interval timing information and it is suggested that state-dependent networks may suffice for that purpose. Happening, therefore, is perceived at a moment and is constituted by an information structure of connected recent historical information.     

Individual differences in vulnerability to subjective time distortion1

Time duration is perceived to be longer when accompanied by dynamic sensory stimulation than when accompanied by static stimulation. This distortion of time perception is thought to be due to the acceleration of an internal pacemaker that has been assumed to be the main component of temporal judgments. In order to investigate whether the function of the internal pacemaker is modality dependent or independent, we examined the correlation of visual flicker and auditory flutter effects on a temporal production task. While seeing a 10‐Hz visual flicker or hearing a 10‐Hz auditory flutter, participants estimated a duration of 2500 ms as accurately as possible by pressing a button. The results showed a significant within‐individual correlation between the time distortion due to visual flicker and that due to auditory flutter. Additionally, we found that time distortion due to auditory flutter tended to be larger in female participants than in male participants. These results suggest that the mechanisms underlying subjective time dilation are similar between vision and audition within individuals, but that they vary across individuals.     

Time and memory: towards a pacemaker-free theory of interval timing

A popular view of interval timing in animals is that it is driven by a discrete pacemaker-accumulator mechanism that yields a linear scale for encoded time. But these mechanisms are fundamentally at odds with the Weber law property of interval timing, and experiments that support linear encoded time can be interpreted in other ways. We argue that the dominant pacemaker-accumulator theory, scalar expectancy theory (SET), fails to explain some basic properties of operant behavior on interval-timing procedures and can only accommodate a number of discrepancies by modifications and elaborations that raise questions about the entire theory. We propose an alternative that is based on principles of memory dynamics derived from the multiple-time-scale (MTS) model of habituation. The MTS timing model can account for data from a wide variety of time-related experiments: proportional and Weber law temporal discrimination, transient as well as persistent effects of reinforcement omission and reinforcement magnitude, bisection, the discrimination of relative as well as absolute duration, and the choose-short effect and its analogue in number-discrimination experiments. Resemblances between timing and counting are an automatic consequence of the model. We also argue that the transient and persistent effects of drugs on time estimates can be interpreted as well within MTS theory as in SET. Recent real-time physiological data conform in surprising detail to the assumptions of the MTS habituation model. Comparisons between the two views suggest a number of novel experiments.     

Probing the cognitive representation of musical time: structural constraints on the perception of timing perturbations.

To determine whether structural factors interact with the perception of musical time, musically literate listeners were presented repeatedly with eight-bar musical excerpts, realized with physically regular timing on an electronic piano. On each trial, one or two randomly chosen time intervals were lengthened by a small amount, and the score. The resulting detection accuracy profile across all positions in each musical excerpt showed pronounced dips in places where lengthening would typically occur in an expressive (temporally modulated) performance. False alarm percentages indicated that certain tones seemed longer a priori, and these were among the ones whose actual lengthening was easiest to detect. The detection accuracy and false alarm profiles were significantly correlated with each other and with the temporal microstructure of expert performances, as measured from sound recordings by famous artists. Thus the detection task apparently tapped into listeners' musical thought and revealed their expectations about the temporal microstructure of music performance. These expectations, like the timing patterns of actual performances, derive from the cognitive representation of musical structure, as cued by a variety of systemic factors (grouping, meter, harmonic progression) and their acoustic correlates. No simple psycho-acoustic explanation of the detection accuracy profiles was evident. The results suggest that the perception of musical time is not veridical but "warped" by the structural representation. This warping may provide a natural basis for performance evaluation: expected timing patterns sound more or less regular, unexpected ones irregular. Parallels to language performance and perception are noted.     

Temporal control and coordination: the multiple timer model.

We consider the psychological and neurological mechanisms involved in timed behaviors, motor or perceptual tasks that emphasize the temporal relationship between successive events. Two general models for representing temporal information are described. In one model, temporal information is based on the oscillatory activity of an endogenous pacemaker; in the other model, temporal information is interval-based with distinct elements devoted to representing different intervals. We incorporate the interval hypothesis into a process model, the multiple timer model, to account for the timing and coordination of repetitive movements. The model accounts for the patterns of temporal stability observed within each effector and offers a novel account of between-effector coordination. Finally, we consider how timing and temporal coordination may be instantiated in the nervous system.     

Attention and interference in prospective and retrospective timing.

Subjects listened to a series of musical selections and then judged the duration of each selection. Some subjects were informed beforehand that timing was involved (prospective timing) whereas others were informed afterwards (retrospective timing). Half the groups performed a concurrent proofreading task during stimulus presentation. The results showed a trade-off between temporal and nontemporal task performance: prospective-timing groups were more accurate in judging time and were worse at proofreading, whereas retrospective-timing groups were relatively poor at judging time but better at proofreading. This pattern is consistent with Michon's notion of an essential equivalence between temporal and nontemporal processing, and supports the predictions of an attentional allocation model of timing. The proofreading task interfered both with prospective and with retrospective timing, and both types of time judgments were influenced in the same way by effects of stimulus context. These results imply that similar timing processes operate under prospective and retrospective conditions.     

言语工作记忆的保持对时间知觉的影响*

采用工作记忆和时间判断的双任务范式,探讨了言语工作记忆的保持过程对时间知觉的影响。研究中操作记忆负荷和任务之间的时间间隔(ISI:记忆刺激消失到时间判断任务开始之间的时间间隔)。结果发现,记忆负荷越大,知觉到的时间越短,韦伯比例越低,反应时间越长;ISI越短,知觉到的时间变短,反应时间越长,这表明知觉时间和反应决策是一致的,不存在累加时间和反应判断之间的trade-off。但是记忆负荷和ISI的交互作用不显著。结果表明记忆负荷和ISI以不同的方式影响时间判断,言语工作记忆的保持和时间加工共享工作记忆资源。     

Evidence against the relative invariance of timing in handwriting

Gentner (1987) has called into question the role of timing information in a number of motor behaviours. The status of an invariant relative timing model for handwriting, however, is still unclear, due to lack of previous studies that have applied appropriate tests to a suitable database.

This study employs a direct application of the tests proposed by Gentner (1987) to handwriting samples collected from adult subjects, to ascertain whether an invariant temporal pattern was retained across changes in size and speed of writing.

In line with Gentner's (1987) study of typing, the findings are strongly against the invariant relative timing model and bring into question motor program models that posit timing as an independent parameter.     

The relative efficacy of different forms of knowledge of results for the learning of a new relative timing pattern

The goal of the present study was to determine the relative efficacy of verbal and auditory knowledge of results for promoting learning of a new constrained relative timing pattern. In a series of four experiments we compared the efficiency of verbal knowledge of results to that of auditory knowledge of results. The results of all four experiments revealed that verbal knowledge of result is a very effective source of information to promote learning of a new imposed relative timing pattern. Auditory knowledge of results favoured learning of a new relative timing pattern in a very limited set of circumstances. In the present study, this was only the case when movement velocity remained constant from one segment of the task to the next and if it resulted in an unfamiliar temporal pattern. The results of all four experiments also provided evidence that movement parameterization and relative timing are independent processes that can be developed in parallel.     

Alerting attention and time perception in children

This experiment investigated the effect of a signal (i.e., a click) warning of the arrival of a stimulus to be timed on temporal discrimination in children aged 3, 5, and 8 years (N=86), using a bisection task with visual stimuli ranging from 0.5 to 2s or 1 to 4s. In all groups, the psychophysical functions were orderly with the proportion of long responses increasing with the stimulus duration, although the steepness of functions increased with age. Stimulus durations were judged to be longer with than without the click in all age groups. With the click, time sensitivity also improved and more particularly in the younger children. The statistical results suggest, within the framework of the scalar timing theory, that the click reduces the closing latency of the switch that connects the pacemaker to the accumulator in the internal clock and also reduces its trial-by-trial variability.     

Les effets de la modalité sensorielle sur la perception du temps

The subjective duration of an event can be influenced by the modality of the signal demarcating that event. For example, auditory signals are often judged as of longer duration than equivalent duration visual signals. Within the framework of pacemaker-accumulator models of timing, such modality effects raise the question of whether the internal clock is modality specific or amodal. The answer to this question is quite important for the development of cognitively and neurologically realistic models of timing and time perception. Here, we argue that the internal clock has both modality specific and amodal components. Specifically, we claim there is a common amodal pacemaker, but the switch-accumulator systems are modality specific. Moreover, we also posit that long-term memory representations of duration are stored amodally.