Explicit Understanding of Duration Develops Implicitly through Action

Teachers' report of sense of time in kindergarten predicts children's time-processing skills in first grade

The main aim of this longitudinal study was to evaluate if a questionnaire measuring the sense of time, filled in by teachers and parents in the last year of kindergarten, was able to predict children's time-processing skills at the end of 1st grade. The sample included 131 children (initial mean age = 4.77 ± 0.29 years) tested three times in a 2-year period with tasks of time reproduction, time discrimination, and comparison of durations. One of their parents and teachers filled in a questionnaire about children's sense of time both in kindergarten and 1st grade. The teacher version of the questionnaire administered in kindergarten was able to predict most of the time-processing tasks at the end of 1st grade. The parent version of the questionnaire was not able to predict children's performance in these tasks. Different developmental trajectories of time reproduction and time discrimination were observed. This study supports the role of preschool teachers as skilled evaluators of children's time-processing skills.

Memory capacity as the core mechanism of the development of space-time interferences in children

This study investigated the development of spatiotemporal perceptual interactions in 5-to-7 years old children. Participants reproduced the temporal and spatial interval between sequentially presented visual stimuli. The time and spacing between stimuli were experimentally manipulated. In addition, cognitive capacities were assessed using neuropsychological tests. Results revealed that starting at 5 years old, children exhibited spatial biases in their time estimations and temporal biases in their spatial estimations, pointing at space-time interference. In line with developmental improvement of temporal and spatial abilities, these spatiotemporal biases decreased with age. Importantly, short-term memory capacity was a predictor of space-time interference pointing to shared cognitive mechanisms between time and space processing. Our results support the symmetrical hypothesis that proposes a common neurocognitive mechanism for processing time and space.

Embodying Time in the Brain: A Multi-Dimensional Neuroimaging Meta-Analysis of 95 Duration Processing Studies

Time is an omnipresent aspect of almost everything we experience internally or in the external world. The experience of time occurs through such an extensive set of contextual factors that, after decades of research, a unified understanding of its neural substrates is still elusive. In this study, following the recent best-practice guidelines, we conducted a coordinate-based meta-analysis of 95 carefully-selected neuroimaging papers of duration processing. We categorized the included papers into 14 classes of temporal features according to six categorical dimensions. Then, using the activation likelihood estimation (ALE) technique we investigated the convergent activation patterns of each class with a cluster-level family-wise error correction at p < 0.05. The regions most consistently activated across the various timing contexts were the pre-SMA and bilateral insula, consistent with an embodied theory of timing in which abstract representations of duration are rooted in sensorimotor and interoceptive experience, respectively. Moreover, class-specific patterns of activation could be roughly divided according to whether participants were timing auditory sequential stimuli, which additionally activated the dorsal striatum and SMA-proper, or visual single interval stimuli, which additionally activated the right middle frontal and inferior parietal cortices. We conclude that temporal cognition is so entangled with our everyday experience that timing stereotypically common combinations of stimulus characteristics reactivates the sensorimotor systems with which they were first experienced.

Temporal unpredictability increases error monitoring as revealed by EEG-EMG investigation

Reacting in an unpredictable context increases error monitoring as evidenced by greater error-related negativity (ERN), an electrophysiological marker linked to an evaluation of response outcomes. We investigated whether ERN also increased when participants evaluated their responses to events that appeared in unpredictable versus predictable moments in time. We complemented electroencephalographic (EEG) analysis of cortical activity by measuring performance monitoring processes at the peripheral level using electromyography (EMG). Specifically, we used EMG data to quantify how temporal unpredictability would affect motor time (MT), the interval between the onset of muscle activity, and the mechanical response. MT increases following errors, indexing online error detection, and an attempt to stop incorrect actions. In our temporally cued version of the stop-signal task, symbolic cues predicted (temporally predictable condition) or not (temporally unpredictable condition) the onset of a target. In 25% of trials, an auditory signal occurred shortly after the target presentation, informing participants that they should inhibit their response completely. Response times were slower, and fewer inhibitory errors were made during temporally unpredictable than predictable trials, indicating enhanced control of unwanted actions when target onset time was unknown. Importantly, the ERN to inhibitory errors was greater in temporally unpredictable relative to temporally predictable conditions. Similarly, EMG data revealed prolonged MT when reactions to temporally unpredictable targets had not been stopped. Taken together, our results show that a temporally unpredictable environment increases the control of unwanted actions, both at cortical and peripheral levels, suggesting a higher subjective cost of maladaptive responses to temporally uncertain events.

Keeping time and rhythm by internal simulation of sensory stimuli and behavioral actions

Effective behavior often requires synchronizing our actions with changes in the environment. Rhythmic changes in the environment are easy to predict, and we can readily time our actions to them. Yet, how the brain encodes and maintains rhythms is not known. Here, we trained primates to internally maintain rhythms of different tempos and performed large-scale recordings of neuronal activity across the sensory-motor hierarchy. Results show that maintaining rhythms engages multiple brain areas, including visual, parietal, premotor, prefrontal, and hippocampal regions. Each recorded area displayed oscillations in firing rates and oscillations in broadband local field potential power that reflected the temporal and spatial characteristics of an internal metronome, which flexibly encoded fast, medium, and slow tempos. The presence of widespread metronome-related activity, in the absence of stimuli and motor activity, suggests that internal simulation of stimuli and actions underlies timekeeping and rhythm maintenance.

The Motor of Time: Coupling Action to Temporally Predictable Events Heightens Perception

Timing and motor function share neural circuits and dynamics, which underpin their close and synergistic relationship. For instance, the temporal predictability of a sensory event optimizes motor responses to that event. Knowing when an event is likely to occur lowers response thresholds, leading to faster and more efficient motor behavior though in situations of response conflict can induce impulsive and inappropriate responding. In turn, through a process of active sensing, coupling action to temporally predictable sensory input enhances perceptual processing. Action not only hones perception of the event's onset or duration, but also boosts sensory processing of its non-temporal features such as pitch or shape. The effects of temporal predictability on motor behavior and sensory processing involve motor and left parietal cortices and are mediated by changes in delta and beta oscillations in motor areas of the brain.

Time processing in neurological and psychiatric conditions

A central question in understanding cognition and pathology-related cognitive changes is how we process time. However, time processing difficulties across several neurological and psychiatric conditions remain seldom investigated. The aim of this review is to develop a unifying taxonomy of time processing, and a neuropsychological perspective on temporal difficulties. Four main temporal judgments are discussed: duration processing, simultaneity and synchrony, passage of time, and mental time travel. We present an integrated theoretical framework of timing difficulties across psychiatric and neurological conditions based on selected patient populations. This framework provides new mechanistic insights on both (a) the processes involved in each temporal judgement, and (b) temporal difficulties across pathologies. By identifying underlying transdiagnostic time-processing mechanisms, this framework opens fruitful avenues for future research.

Lost in time: Relocating the perception of duration outside the brain

It is well-accepted in neuroscience that animals process time internally to estimate the duration of intervals lasting between one and several seconds. More than 100 years ago, Henri Bergson nevertheless remarked that, because animals have memory, their inner experience of time is ever-changing, making duration impossible to measure internally and time a source of change. Bergson proposed that quantifying the inner experience of time requires its externalization in movements (observed or self-generated), as their unfolding leaves measurable traces in space. Here, studies across species are reviewed and collectively suggest that, in line with Bergson's ideas, animals spontaneously solve time estimation tasks through a movement-based spatialization of time. Moreover, the well-known scalable anticipatory responses of animals to regularly spaced rewards can be explained by the variable pressure of time on reward-oriented actions. Finally, the brain regions linked with time perception overlap with those implicated in motor control, spatial navigation and motivation. Thus, instead of considering time as static information processed by the brain, it might be fruitful to conceptualize it as a kind of force to which animals are more or less sensitive depending on their internal state and environment.

Time discrimination and change detection could share a common brain network: findings of a task-based fMRI study

Introduction

Over the past few years, several studies have described the brain activation pattern related to both time discrimination (TD) and change detection processes. We hypothesize that both processes share a common brain network which may play a significant role in more complex cognitive processes. The main goal of this proof-of-concept study is to describe the pattern of brain activity involved in TD and oddball detection (OD) paradigms, and in processes requiring higher cognitive effort.

Methods

We designed an experimental task, including an auditory test tool to assess TD and OD paradigms, which was conducted under functional magnetic resonance imaging (fMRI) in 14 healthy participants. We added a cognitive control component into both paradigms in our test tool. We used the general linear model (GLM) to analyze the individual fMRI data images and the random effects model for group inference.

Results

We defined the areas of brain activation related to TD and OD paradigms. We performed a conjunction analysis of contrast TD (task > control) and OD (task > control) patterns, finding both similarities and significant differences between them.

Discussion

We conclude that change detection and other cognitive processes requiring an increase in cognitive effort require participation of overlapping functional and neuroanatomical components, suggesting the presence of a common time and change detection network. This is of particular relevance for future research on normal cognitive functioning in the healthy population, as well as for the study of cognitive impairment and clinical manifestations associated with various neuropsychiatric conditions such as schizophrenia.

Development and relationship between the judgment of the speed of passage of time and the judgment of duration in children

This study examined the relationships between the awareness of the speed of the passage of time, the judgment of durations and experiential factors in children aged 4-9 years. They were asked to judge the duration and the speed of the passage of time for different intervals (second and minutes), and to rate their feelings (arousal, happiness, sadness, and task difficulty) during each interval. The results indicated that 8-9-year-olds' judgment of the passage of time is extremely flexible and context-dependent, representing the duration and/or the individual changes in subjective experience (emotion). In contrast, young children's judgment of the passage of time was not related to duration. However, their judgments were not given randomly. They judged that time passed more quickly when they felt happier and more alert. The passage-of-time judgment was therefore initially grounded in emotional and sensory-motor experience, i.e., in their perception of changes (acceleration and deceleration) in self-movement (successions of states and their extension). Therefore, duration judgment and passage-of-time judgment initially develop separately and are later combined when children understand the logical link between speed and duration.

Motion duration is overestimated behind an occluder in action and perception tasks

Motion estimation behind an occluder is a common task in situations like crossing the street or passing another car. People tend to overestimate the duration of an object's motion when it gets occluded for subsecond motion durations. Here, we explored (a) whether this bias depended on the type of interceptive action: discrete keypress versus continuous reach and (b) whether it was present in a perception task without an interceptive action. We used a prediction-motion task and presented a bar moving across the screen with a constant velocity that later became occluded. In the action task, participants stopped the occluded bar when they thought the bar reached the goal position via keypress or reach. They were more likely to stop the bar after it passed the goal position regardless of the action type, suggesting that the duration of occluded motion was overestimated (or its speed was underestimated). In the perception task, where participants judged whether a tone was presented before or after the bar reached the goal position, a similar bias was observed. In both tasks, the bias was near constant across motion durations and directions and grew over trials. We speculate that this robust bias may be due to a temporal illusion, Bayesian slow-motion prior, or the processing of the visible-occluded boundary crossing. Understanding its exact mechanism, the conditions on which it depends, and the relative roles of speed and time perception requires further research.

Modality-Attention Promotes the Neural Effects of Precise Timing Prediction in Early Sensory Processing

Precise timing prediction (TP) enables the brain to accurately predict the occurrence of upcoming events in millisecond timescale, which is fundamental for adaptive behaviors. The neural effect of the TP within a single sensory modality has been widely studied. However, less is known about how precise TP works when the brain is concurrently faced with multimodality sensory inputs. Modality attention (MA) is a crucial cognitive function for dealing with the overwhelming information induced by multimodality sensory inputs. Therefore, it is necessary to investigate whether and how the MA influences the neural effects of the precise TP. This study designed a visual–auditory temporal discrimination task, in which the MA was allocated to visual or auditory modality, and the TP was manipulated into no timing prediction (NTP), matched timing prediction (MTP), and violated timing prediction (VTP) conditions. Behavioral and electroencephalogram (EEG) data were recorded from 27 subjects, event-related potentials (ERP), time–frequency distributions of inter-trial coherence (ITC), and event-related spectral perturbation (ERSP) were analyzed. In the visual modality, precise TP led to N1 amplitude variations and 200–400 ms theta ITC. Such variations only emerged when the MA was attended. In auditory modality, the MTP had the largest P2 amplitude and delta ITC than other TP conditions when the MA was attended, whereas the distinctions disappeared when the MA was unattended. The results suggest that the MA promoted the neural effects of the precise TP in early sensory processing, which provides more neural evidence for better understanding the interactions between the TP and MA.

Influence of Recent Trial History on Interval Timing

Interval timing is involved in a variety of cognitive behaviors such as associative learning and decision-making. While it has been shown that time estimation is adaptive to the temporal context, it remains unclear how interval timing behavior is influenced by recent trial history. Here we found that, in mice trained to perform a licking-based interval timing task, a decrease of inter-reinforcement interval in the previous trial rapidly shifted the time of anticipatory licking earlier. Optogenetic inactivation of the anterior lateral motor cortex (ALM), but not the medial prefrontal cortex, for a short time before reward delivery caused a decrease in the peak time of anticipatory licking in the next trial. Electrophysiological recordings from the ALM showed that the response profiles preceded by short and long inter-reinforcement intervals exhibited task-engagement-dependent temporal scaling. Thus, interval timing is adaptive to recent experience of the temporal interval, and ALM activity during time estimation reflects recent experience of interval.

Temporal learning in the suprasecond range: insights from cognitive style

The acquisition of information on the timing of events or actions (temporal learning) occurs in both the subsecond and suprasecond range. However, although relevant differences between participants have been reported in temporal learning, the role of dimensions of individual variability in affecting performance in such tasks is still unclear. Here we investigated this issue, assessing the effect of field-dependent/independent cognitive style on temporal learning in the suprasecond range. Since different mechanisms mediate timing when a temporal representation is self-generated, and when it depends on an external referent, temporal learning was assessed in two conditions. Participants observed a stimulus across six repetitions and reproduced it. Unbeknownst to them, in an internally-based learning (IBL) condition, the stimulus duration was fixed within a trial, although the number of events defining it varied; in an externally-cued learning (ECL) condition, the stimulus was defined by the same number of events within each trial, although its duration varied. The effect of the reproduction modality was also assessed (motor vs. perceptual). Error scores were higher in IBL compared to ECL; the reverse was true for variability. Field-independent individuals performed better than field-dependent ones only in IBL, as further confirmed by correlation analyses. Findings provide evidence that differences in dimensions of variability in high-level cognitive functioning, such as field dependence/independence, significantly affect temporal learning in the suprasecond range, and that this effect depends on the type of temporal representation fostered by the specific task demands.

Intrinsic hippocampal connectivity is associated with individual differences in retrospective duration processing

The estimation of incidentally encoded durations of time intervals (retrospective duration processing) is thought to rely on the retrieval of contextual information associated with a sequence of events, automatically encoded in medial temporal lobe regions. "Time cells" have been described in the hippocampus (HC), encoding the temporal progression of events and their duration. However, whether the HC supports explicit retrospective duration judgments in humans, and which neural dynamics are involved, is still poorly understood. Here we used resting-state fMRI to test the relation between variations in intrinsic connectivity patterns of the HC, and individual differences in retrospective duration processing, assessed using a novel task involving the presentation of ecological stimuli. Results showed that retrospective duration discrimination performance predicted variations in the intrinsic connectivity of the bilateral HC with the right precentral gyrus; follow-up exploratory analyses suggested a role of the CA1 and CA4/DG subfields in driving the observed pattern. Findings provide insights on neural networks associated with implicit processing of durations in the second range.

Exploring spatiotemporal interactions: On the superiority of time over space

Space and time mutually influence each other such that space affects time estimation (space-on-time effect), and conversely (time-on-space effect). These reciprocal interferences suggest that space and time are intrinsically linked in the human mind. Yet, recent evidence for an asymmetrical advantage for space over time challenges the classical theoretical interpretation. In the present study, we tested whether the superiority of space over time in magnitude interference depends on the cognitive resources engaged in the spatial task. We conducted three experiments in which participants performed judgments on temporal intervals and spatial distances in separate blocks. In each trial, two dots were successively flashed at various locations, and participants were to judge whether the duration or distance between the dots was short or long. To manipulate cognitive demands in the spatial task, distances varied across experiments (highly discriminable for the non-demanding spatial task in Experiment 1 and scarcely discriminable for the demanding spatial task in Experiment 2). Importantly, this manipulation tended to enhance perceptual sensitivity (as indexed by Weber Ratios) but slowed down the decision process (as indexed by response times) in the demanding experiment. Our results provide evidence for robust space-on-time and time-on-space effects (Experiments 1 and 2). More crucially, the involvement of cognitive resources in a demanding spatial task causes a massive time-on-space effect: Spatial judgments are indeed more influenced by irrelevant temporal information than the reverse (Experiments 2 and 3). Overall, the flexibility of spatiotemporal interferences has direct theoretical implications and questions the origins of space-time interaction.

The ages of zone of proximal development for retrospective time assessment and anticipation of time event

From childhood to adulthood, an individual's ability to estimate and anticipate the timing of events changes continuously. This study investigated the ability of 287 children aged 5-14 years to estimate the duration of prior events and anticipate the timing of future events for determination of the age at which children improve their timing skills. The Luria neuropsychological assessment battery and the Wechsler Intelligence Scale for Children (WISC-IV) were applied to find correlations between timing skills and the development of cognitive functions. The findings demonstrated that retrospective estimation of duration has a zone of proximal development in children between the ages of six to eight; in these children, the accuracy of time assessment significantly improved after receiving the prompt. However, improvement in time estimation was significantly lower in those children who achieved lower results in the attention and memory tests and demonstrated reduced spatial and verbal reasoning skills. The zone of proximal development for the ability to anticipate the timing of future events was demonstrated in children between the ages of nine to eleven years. The improvement of time anticipation was negatively correlated with the number of mistakes made during the dynamic praxis test.

The neural bases for timing of durations

Durations are defined by a beginning and an end, and a major distinction is drawn between durations that start in the present and end in the future ('prospective timing') and durations that start in the past and end either in the past or the present ('retrospective timing'). Different psychological processes are thought to be engaged in each of these cases. The former is thought to engage a clock-like mechanism that accurately tracks the continuing passage of time, whereas the latter is thought to engage a reconstructive process that utilizes both temporal and non-temporal information from the memory of past events. We propose that, from a biological perspective, these two forms of duration 'estimation' are supported by computational processes that are both reliant on population state dynamics but are nevertheless distinct. Prospective timing is effectively carried out in a single step where the ongoing dynamics of population activity directly serve as the computation of duration, whereas retrospective timing is carried out in two steps: the initial generation of population state dynamics through the process of event segmentation and the subsequent computation of duration utilizing the memory of those dynamics.

Oscillation/Coincidence-Detection Models of Reward-Related Timing in Corticostriatal Circuits

The major tenets of beat-frequency/coincidence-detection models of reward-related timing are reviewed in light of recent behavioral and neurobiological findings. This includes the emphasis on a core timing network embedded in the motor system that is comprised of a corticothalamic-basal ganglia circuit. Therein, a central hub provides timing pulses (i.e., predictive signals) to the entire brain, including a set of distributed satellite regions in the cerebellum, cortex, amygdala, and hippocampus that are selectively engaged in timing in a manner that is more dependent upon the specific sensory, behavioral, and contextual requirements of the task. Oscillation/coincidence-detection models also emphasize the importance of a tuned ‘perception’ learning and memory system whereby target durations are detected by striatal networks of medium spiny neurons (MSNs) through the coincidental activation of different neural populations, typically utilizing patterns of oscillatory input from the cortex and thalamus or derivations thereof (e.g., population coding) as a time base. The measure of success of beat-frequency/coincidence-detection accounts, such as the Striatal Beat-Frequency model of reward-related timing (SBF), is their ability to accommodate new experimental findings while maintaining their original framework, thereby making testable experimental predictions concerning diagnosis and treatment of issues related to a variety of dopamine-dependent basal ganglia disorders, including Huntington’s and Parkinson’s disease.

How movements shape the perception of time

In order to keep up with a changing environment, mobile organisms must be capable of deciding both where and when to move. This precision necessitates a strong sense of time, as otherwise we would fail in many of our movement goals. Yet, despite this intrinsic link, only recently have researchers begun to understand how these two features interact. Primarily, two effects have been observed: movements can bias time estimates, but they can also make them more precise. Here we review this literature and propose that both effects can be explained by a Bayesian cue combination framework, in which movement itself affords the most precise representation of time, which can influence perception in either feedforward or active sensing modes.

Simultaneous time processing in children and adults: When attention predicts temporal interference effects

Children from 5 to 8 years of age, as well as adults, performed a temporal reproduction task in both a solo-timing condition and a multi-timing condition, with different durations presented simultaneously. In the multi-timing condition, all durations were processed because the participants did not know in advance which stimulus needed to be judged. In a first experiment, two or three durations were presented with a synchrony of their onset. In a second experiment, two durations were presented simultaneously with asynchrony of their offset, different lengths of the concurrent duration, and different presentation orders. In addition, the participants' cognitive abilities in terms of selective attention, as well as short-term and working memory, were assessed with different neuropsychological tests. The results of both experiments showed that children and adults alike were able to process multiple durations simultaneously. However, the simultaneous presentation of different durations generated a temporal interference effect in children and adults, resulting in longer and more variable time estimates. This temporal interference effect was nevertheless higher in children due to their limited attention capacities. Therefore, a developmental improvement in the ability to process different durations simultaneously is related to the cognitive development of attention capacities.

Perception of saccadic reaction time

That saccadic reaction times (SRTs) may depend on reinforcement contingencies has been repeatedly demonstrated. It follows that one must be able to discriminate one’s latencies to adequately assign credit to one’s actions, which is to connect behaviour to its consequence. To quantify the ability to perceive one’s SRT, we used an adaptive procedure to train sixteen participants in a stepping visual target saccade paradigm. Subsequently, we measured their RTs perceptual threshold at 75% in a conventional constant stimuli procedure. For each trial, observers had to saccade to a stepping target. Then, in a 2-AFC task, they had to choose one value representing the actual SRT, while the other value proportionally differed from the actual SRT. The relative difference between the two alternatives was computed by either adding or subtracting from the actual SRT a percent-difference value randomly chosen among a fixed set. Feedback signalling the correct choice was provided after each response. Overall, our results showed that the 75% SRT perceptual threshold averaged 23% (about 40 ms). The ability to discriminate small SRT differences provides support for the possibility that the credit assignment problem may be solved even for short reaction times.

The role of action intentionality and effector in the subjective expansion of temporal duration after saccadic eye movements

Visual perception is based on periods of stable fixation separated by saccadic eye movements. Although naive perception seems stable (in space) and continuous (in time), laboratory studies have demonstrated that events presented around the time of saccades are misperceived spatially and temporally. Saccadic chronostasis, the "stopped clock illusion", represents one such temporal distortion in which the movement of the clock hand after the saccade is perceived as lasting longer than usual. Multiple explanations for chronostasis have been proposed including action-backdating, temporal binding of the action towards the moment of its effect ("intentional binding") and post-saccadic temporal dilation. The current study aimed to resolve this debate by using different types of action (keypress vs saccade) and varying the intentionality of the action. We measured both perceived onset of the motor action and perceived onset of an auditory tone presented at different delays after the keypress/saccade. The results showed intentional binding for the keypress action, with perceived motor onset shifted forwards in time and the time of the tone shifted backwards. Saccades resulted in the opposite pattern, showing temporal expansion rather than compression, especially with cued saccades. The temporal illusion was modulated by intentionality of the movement. Our findings suggest that saccadic chronostasis is not solely dependent on a backward shift in perceived saccade onset, but instead reflects a temporal dilation. This percept of an effectively "longer" period at the beginning of a new fixation may reflect the pattern of suppressed, and then enhanced, visual processing around the time of saccades.

The influence of performing gesture type on interpersonal musical timing, and the role of visual contact and tempo

Bodily gestures play an important role in the communication of expressive intentions between humans. Music ensemble performance, as an outstanding example of nonverbal human communication, offers an exemplary context to study and understand the gestural control and communication of these expressive intentions. An important mechanism in music ensemble performance is the anticipation and control of interpersonal timing. When performing, musicians are involved in a complex system of mutual adaptation which is not completely understood so far. In this study, we investigated the role of performers' gestures in the mediation process of interpersonal timing in a dyad performance. Therefore, we designed an experiment in which we controlled for the use of hand and arm movements in a musical task, in which dyads were asked to synchronously tap out a melody. Next to their comfortable/natural way of tapping, we instructed participants to either perform pronounced expressive hand and arm gestures in between successive taps, or to restrict from any overt body movement. In addition, we looked at effects of visual contact (yes/no) and tempo (slow: 50 beats per minute; fast: 100 beats per minute). The results show that performers' gestures improve interpersonal musical timing, in terms of the consistency and accuracy of onset asynchronies, and of the variability of produced inter-onset intervals. Interestingly, we found that the use of expressive gestures, in regard to comfortable/natural movements, add to these positive timing effects, but only when there is visual contact and at the slow tempo. In addition, we found that the type of gestures employed by musicians may modulate leader-follower dynamics. Together, these findings are explained by human anticipation mechanisms facilitated by gesturing, shedding new light on the principles underlying human communication of expressive intentions, through music.

The developmental profile of temporal binding: From childhood to adulthood

Temporal binding refers to a phenomenon whereby the time interval between a cause and its effect is perceived as shorter than the same interval separating two unrelated events. We examined the developmental profile of this phenomenon by comparing the performance of groups of children (aged 6–7, 7–8, and 9–10 years) and adults on a novel interval estimation task. In Experiment 1, participants made judgements about the time interval between (a) their button press and a rocket launch, and (b) a non-causal predictive signal and rocket launch. In Experiment 2, an additional causal condition was included in which participants made judgements about the interval between an experimenter’s button press and the launch of a rocket. Temporal binding was demonstrated consistently and did not change in magnitude with age: estimates of delay were shorter in causal contexts for both adults and children. In addition, the magnitude of the binding effect was greater when participants themselves were the cause of an outcome compared with when they were mere spectators. This suggests that although causality underlies the binding effect, intentional action may modulate its magnitude. Again, this was true of both adults and children. Taken together, these results are the first to suggest that the binding effect is present and developmentally constant from childhood into adulthood.

Turning the body into a clock: Accurate timing is facilitated by simple stereotyped interactions with the environment

How animals adapt their behavior according to regular time intervals between events is not well understood, especially when intervals last several seconds. One possibility is that animals use disembodied internal neuronal representations of time to decide when to initiate a given action at the end of an interval. However, animals rarely remain immobile during time intervals but tend to perform stereotyped behaviors, raising the possibility that motor routines improve timing accuracy. To test this possibility, we used a task in which rats, freely moving on a motorized treadmill, could obtain a reward if they approached it after a fixed interval. Most animals took advantage of the treadmill length and its moving direction to develop, by trial-and-error, the same motor routine whose execution resulted in the precise timing of their reward approaches. Noticeably, when proficient animals did not follow this routine, their temporal accuracy decreased. Then, naïve animals were trained in modified versions of the task designed to prevent the development of this routine. Compared to rats trained in the first protocol, these animals didn't reach a comparable level of timing accuracy. Altogether, our results indicate that timing accuracy in rats is improved when the environment affords cues that animals can incorporate into motor routines.

Embodied time and the out-of-body experience of the self

Using an out-of-body paradigm, the present study provided further empirical evidence for the theory of embodied time by suggesting that the body-self plays a key role in time judgments. Looking through virtual reality glasses, the participants saw the arm of a mannequin instead of their own arm. They had to judge the duration of the interval between two (perceived) touches applied to the mannequin's body after a series of strokes had been viewed being made to the mannequin and tactile strokes had been administered to the participants themselves. These strokes were administered either synchronously or asynchronously. During the interval, a pleasant (touch with a soft paintbrush) or an unpleasant stimulation (touch with a pointed knife) was applied to the mannequin. The results showed that the participants felt the perceived tactile stimulations in their own bodies more strongly after the synchronous than the asynchronous stroking condition, a finding which is consistent with the out-of-body illusion. In addition, the interval duration was judged longer in the synchronous than in the asynchronous condition. This time distortion increased the greater the individual out-of-body experience was. Our results therefore highlight the importance of the awareness of the body-self in the processing of time, i.e., the significance of embodied time.

Temporal Preparation, Impulsivity and Short-Term Memory in Depression

Patient suffering of major depressive disorder (MDD) often complain that subjective time seems to "drag" with respect to physical time. This may point toward a generalized dysfunction of temporal processing in MDD. In the present study, we investigated temporal preparation in MDD. "Temporal preparation" refers to an increased readiness to act before an expected event; consequently, reaction time should be reduced. MDD patients and age-matched controls were required to make a saccadic eye movement between a central and an eccentric visual target after a variable duration preparatory period. We found that MDD patients produced a larger number of premature saccades, saccades initiated prior to the appearance of the expected stimulus. These saccades were not temporally controlled; instead, they seemed to reflect reduced inhibitory control causing oculomotor impulsivity. In contrast, the latency of visually guided saccades was strongly influenced by temporal preparation in controls; significantly less so, in MDD patients. This observed reduced temporal preparation in MDD was associated with a faster decay of short-term temporal memory. Moreover, in patients producing a lot of premature responses, temporal preparation to early imperative stimuli was increased. In conclusion, reduced temporal preparation and short-term temporal memory in the oculomotor domain supports the hypothesis that temporal processing was altered in MDD patients. Moreover, oculomotor impulsivity interacted with temporal preparation. These observed deficits could reflect other underlying aspects of abnormal time experience in MDD.

Awareness of the passage of time and self-consciousness: What do meditators report?

What do humans mean when they say that time passes quickly or slowly? In this article, we try to respond to this question on the basis of our studies on the judgment of the passage of time and its links with the judgment of physical durations. The awareness of the passage of time when consciousness is altered by meditation is also discussed. A dissociation is then made among the "self-time perspective," the "self-duration" (internal duration), and the "world-duration" (external duration). A link is also established between the self-time perspective and the "narrative self," on one hand, and the self-duration and the "minimal self," on the other hand, that is confirmed in our qualitative analysis of testimonials of four meditators. The awareness of self-duration is thus related to the awareness of the embodied self. When the sense of self is altered and the consciousness of the body is lower, then the subjective experience of internal time changes. However, the mechanisms allowing the disappearance of the self with the feeling of being outside time during meditation remains to be elucidated.

Development of sensorimotor synchronization abilities: Motor and cognitive components

The aim of the present study was to examine both the development of sensorimotor synchronization in children in the age range from 5 to 8 years and the involvement of motor and cognitive capacities. Children performed a spontaneous motor tempo task and a synchronization-continuation task using an external auditory stimulus presented at three different inter-stimulus intervals: 500, 700, and 900 ms. Their motor and cognitive abilities (short-term memory, working memory, and attention) were also assessed with various neuropsychological tests. The results showed some developmental changes in synchronization capacities, with the regularity of tapping and the ability to slow down the tapping rate improving with age. The age-related differences in tapping were nevertheless greater in the continuation phase than in the synchronization phase. In addition, the development of motor capacities explained the age-related changes in performance for the synchronization phase and the continuation phase, although working memory capacities were also involved in the interindividual differences in performance in the continuation phase. The continuation phase is thus more cognitively demanding than the synchronization phase. Consequently, the improvement in sensorimotor synchronization during childhood is related to motor development in the case of synchronization but also to cognitive development with regard to the reproduction and maintenance of the rhythm in memory.

The dynamic effect of context on interval timing in children and adults

Human reproductions of time intervals are often biased toward previously perceived durations, resulting in a central tendency effect. The aim of the current study was to compare this effect of temporal context on time reproductions within children and adults. Children aged from 5 to 7 years, as well as adults, performed a ready-set-go reproduction task with a short and a long duration distribution. A central tendency effect was observed both in children and adults, with no age-difference in the effect of global context on temporal performance. However, the analysis of the effect of local context (trial-by-trial) indicated that younger children relied more on the duration (objective duration) presented in the most recent trial than adults. In addition, statistical analyses of the influence on temporal performance of recently reproduced durations by subjects (subjective duration) revealed that temporal reproductions in adults were influenced by performance drifts, i.e., their evaluation of their temporal error, while children simply relied on the value of reproduced durations on the recent trials. We argue that the central tendency effect was larger in young children due to their noisier internal representation of durations: A noisy system led participants to base their estimation on experienced duration rather than on the evaluation of their judgment.