Development of time

Relieved or disappointed? Children's understanding of how others feel at the cessation of events

People's emotional states are influenced not just by events occurring in the present but also by how events have unfolded in the past and how they are likely to unfold in the future. To what extent do young children understand the ways in which past events can affect current emotions even if they are no longer ongoing? In the current study, we explored children's ability to understand how others feel at the cessation of events-as events change from being present to being past. We asked 97 4- to 6-year-olds (40.2% female) and 35 adults (54.3% female) to judge how characters felt once particular types of events had ended relative to how they felt during these events. We found that from age 4, children judged (as adults do) that the character would feel positive at the cessation of negative events-what we refer to as temporal relief. This understanding of relief occurs earlier than has been shown in previous research. However, children were less likely than adults to judge others as feeling sad at the cessation of positive events-what we refer to as temporal disappointment. Overall, our findings suggest that children not only understand that the cessation of events can affect others' emotions but also recognize that people feel differently following the cessation of positive, negative, and neutral events.

Towards a neurodevelopmental cognitive perspective of temporal processing

The ability to organize and memorize the unfolding of events over time is a fundamental feature of cognition, which develops concurrently with the maturation of the brain. Nonetheless, how temporal processing evolves across the lifetime as well as the links with the underlying neural substrates remains unclear. Here, we intend to retrace the main developmental stages of brain structure, function, and cognition linked to the emergence of timing abilities. This neurodevelopmental perspective aims to untangle the puzzling trajectory of temporal processing aspects across the lifetime, paving the way to novel neuropsychological assessments and cognitive rehabilitation strategies.

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.

Cognitive and plastic recurrent neural network clock model for the judgment of time and its variations

The aim of this study in the field of computational neurosciences was to simulate and predict inter-individual variability in time judgements with different neuropsychological properties. We propose and test a Simple Recurrent Neural Network-based clock model that is able to account for inter-individual variability in time judgment by adding four new components into the clock system: the first relates to the plasticity of the neural system, the second to the attention allocated to time, the third to the memory of duration, and the fourth to the learning of duration by iteration. A simulation with this model explored its fit with participants' time estimates in a temporal reproduction task undertaken by both children and adults, whose varied cognitive abilities were assessed with neuropsychological tests. The simulation successfully predicted 90% of temporal errors. Our Cognitive and Plastic RNN-Clock model (CP-RNN-Clock), that takes into account the interference arising from a clock system grounded in cognition, was thus validated.

Sensorimotor and working memory systems jointly support development of perceptual rhythm processing

We studied the role of sensorimotor and working memory systems in supporting development of perceptual rhythm processing with 119 participants aged 7-12 years. Children were assessed for their abilities in sensorimotor synchronization (SMS; beat tapping), auditory working memory (AWM; digit span), and rhythm discrimination (RD; same/different judgment on a pair of musical rhythm sequences). Multiple regression analysis revealed that children's RD performance was independently predicted by higher beat tapping consistency and greater digit span score, with all other demographic variables (age, sex, socioeconomic status, music training) controlled. The association between RD and SMS was more robust in the slower tempos (60 and 100 beats-per-minute (BPM)) than faster ones (120 and 180 BPM). Critically, the relation of SMS to RD was moderated by age in that RD performance was predicted by beat tapping consistency in younger children (age: 7-9 years), but not in older children (age: 10-12 years). AWM was the only predictor of RD in older children. Together, the current findings demonstrate that the sensorimotor and working memory systems jointly support RD processing during middle-to-late childhood and that the degree of association between the two systems and perceptual rhythm processing is shifted before entering into early adolescence.

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.

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.

Predicting Chinese Preschoolers’ Acquisition of Aspect Markers: A Corpus-Based Study

This study explored the patterns and predictors of aspect marker acquisition of Chinese preschoolers speaking Mandarin Chinese as their first language (L1). Based on a corpus drawn from 157 preschoolers from Beijing, China, this study set out to explore (1) the developmental pattern of aspect marker acquisition; (2) the interactional pattern between grammatical aspect markers and lexical aspects; (3) the production of temporal adverbs with aspect markers; and (4) the predictors of aspect marker acquisition. The main research findings included the following: (1) the Jonckheere–Terpstra test revealed an age-related increase in children’s production of aspect markers, and in particular, there was a significant increase in grammatical aspect markers and lexical aspect subclasses from age 4;6 (Year; Month) onwards; (2) the Friedman’s ANOVAs indicated that -LE was frequently used in combination with most of the lexical aspect subclasses, among them the achievement was the most frequently co-occurring subclass, while the activities came second; (3) a series of Chi-square tests showed that using temporal adverbs in combination with aspect markers became increasingly common among older children; (4) the hierarchical regression analysis identified children’s preschooling experience as a significant predictor of their early aspectual development, after controlling for the other variables.

Detecting Time Concept Competence in Children with Autism Spectrum and Attention Disorders

The importance of time concept in human existence is "ancient history" celebrated in the biblical book Ecclesiastes. Indeed, our time-sensitive mechanisms are literally carved into our biology and neurology on a molecular level, gifting us with neural clocks. However, time in human consciousness is not the time indicated by physical clocks: time is a subjective reality in our psychological makeup due to the nature of the temporal neural mechanisms and unique properties of physical time. Nonetheless, subjective time requires anchoring to physical time which permeates our language, endeavors, and entire existence, a process hinging on time-related skills such as estimates and measures of passage and duration of time. Moreover, accurate time reading, a critical adaptive life-skill, is imperative for effective function in all societal activities. Because it embodies the complexity of the time construct, it is central to instruction of time concept in primary education. It is often measured in children by clock drawings, a cognitive integrative skill with errors pointing to neuroanatomical differences impacting the integrity of executive function. Time competence in children with atypical neurobiological development and high prevalence, as in autism spectrum disorders (ASD), and attention disorders (ADHD), is often compromised, calling for investigation of its function. This thematic review article aims to: 1) discuss the complexity of time concept and its underlying bio-neurological mechanisms, 2) elucidate difficulties children with ASD and those with ADHD exhibit in temporal development, and 3) demonstrate the use of a set of clinical tools in uncovering temporal competence and ecological executive function in two children with ASD, and a child with ADHD, using a clock drawing task and error analyses; children's time knowledge questionnaire; a behavior rating parent questionnaire examining ecological executive function, and parent open-ended questions related to their children's time difficulties. A discussion, directions, and a take-home message round out the article.

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.

Time contraction caused by a distractor in children and adults: The influence of inhibition capacities

The aim of this study was to examine the cognitive processes involved in time contraction caused by a non-temporal distractor during the presentation of a temporal stimulus. To this aim 95 children aged 5 to 8 years old as well as 25 adults were first trained to discriminate, on two visual temporal bisection tasks, a short standard duration (400 or 600 ms) from a long one (1500 or 2400 ms). They had then to decide whether intermediate stimulus duration was more similar to the short or to the long standard duration. Furthermore, a 40 ms distractor taking the form of a 4 cm diameter rosette, either did or did not appear during the temporal stimulus. Participants' task was to report whether they had been exposed to the short or long standard duration. Subsequently, each subject's capacities in terms of memory skills (short term and working memory), as well as attention (selective attention and inhibition), were assessed using different neuropsychological tests. The results showed a shortening effect of the perceived time from non-distractor to distractor trials, which also turned out to attenuate with the age increase. Interestingly, inhibition was found to mediate this effect while the other cognitive variables were found to be of no significance. We therefore discussed the importance of categorizing two attentional interferences: one related to attention control and the other to attentional resources.

The Time Knowledge Questionnaire for children

Based on a definition of time knowledge as the correct representation and use of the various time units, a validated questionnaire, the Time Knowledge Questionnaire (TKQ) has been developed with norms for typically developing children aged 6–11 years. The TKQ is a relatively short (10–45 min) and innovative tool, comprising 25 questions broken down into 7 categories. The TKQ has good internal consistency. A total score and two summary scores are provided, assessing conventional time and estimative time respectively. A clinical application of the tool was shown to be of interest for children with disorders or disabilities.

Inhibitory control and temporal perception in cerebral palsy

Prepotent response inhibition and temporal perception abilities were explored in a sample of individuals with cerebral palsy relative to typically developing peers. The extent to which inhibitory control difficulties might affect temporal processing was also investigated. For this purpose, two inhibitory control tasks and two duration estimation tasks were given to the groups of cerebral palsy and typically developing children. Results showed inhibition and temporal perception problems in the group with cerebral palsy. A relationship was found between inhibition and temporal estimation performances, which indicates that inhibitory control contributes, at least partially, to acquisition of the temporal processing ability.

Teachers, not parents, are able to predict time processing skills in preschoolers

Time processing difficulties are associated with developmental disorders. Questionnaires for assessing children's sense of time are available from primary school, but we lack valid proxy-report tools for younger children, who are not able to complete self-reports. This study aimed to assess the criterion validity of a questionnaire investigating preschoolers' sense of time from the points of view of their parents and teachers. One hundred seventy preschoolers were included in the sample. Their parents and teachers completed the Sense of Time Questionnaire, and the children were administered time reproduction and time discrimination tasks, both concurrently and 7 months later. The assessment of preschoolers' sense of time reported by teachers, but not by parents, predicted the children's time processing skills both concurrently and longitudinally. The teacher version of the Sense of Time Questionnaire constitutes a valid instrument for assessing and predicting preschoolers' time processing skills and can be used for clinical and research purposes STATEMENT OF CONTRIBUTION: What is already known on this subject? Time processing difficulties are associated with developmental disorders such as ADHD and dyscalculia. Early assessment of time processing skills is important for clinical (e.g., screening) and research purposes. We do not have valid questionnaires for assessing sense of time in young children. What the present study adds? The sense of time ability reported by teachers predicts preschoolers' time processing skills. The sense of time ability reported by parents does not predicts preschoolers' time processing skills. The Sense of Time Questionnaire is a valid instrument for investigating time processing skills of 4-6 aged children.

Chinese preschoolers' acquisition of temporal adverbs indicating past, present, and future: a corpus-based study

This study investigated the development of temporal adverbs in early childhood Mandarin. All cases of temporal adverbs indicating the past, present, and future were extracted from the Early Child Mandarin Corpus (168 children in four age groups: 2;6, 3;6, 4;6, 5;6). Data analyses indicated: (1) Mandarin-speaking children produced a repertoire of 21 types of temporal adverbs, and the children in the first age group (M = 2;6) were capable of using temporal adverbs to denote past, present, and future events; (2) within each age group, the children produced significantly more future temporal adverbs than the other two subtypes; and (3) there was a significant age effect that, with increased age, more children were able to produce all subtypes of temporal adverbs. Overall, findings of this corpus-based investigation shed light upon Chinese children's early-attained ability to express the three fundamental notions of time by resorting to the appropriate linguistic devices.

The beneficial effect of synchronized action on motor and perceptual timing in children

We examined the role of action in motor and perceptual timing across development. Adults and children aged 5 or 8 years old learned the duration of a rhythmic interval with or without concurrent action. We compared the effects of sensorimotor versus visual learning on subsequent timing behaviour in three different tasks: rhythm reproduction (Experiment 1), rhythm discrimination (Experiment 2) and interval discrimination (Experiment 3). Sensorimotor learning consisted of sensorimotor synchronization (tapping) to an isochronous visual rhythmic stimulus (ISI = 800 ms), whereas visual learning consisted of simply observing this rhythmic stimulus. Results confirmed our hypothesis that synchronized action during learning systematically benefitted subsequent timing performance, particularly for younger children. Action-related improvements in accuracy were observed for both motor and perceptual timing in 5 years olds and for perceptual timing in the two older age groups. Benefits on perceptual timing tasks indicate that action shapes the cognitive representation of interval duration. Moreover, correlations with neuropsychological scores indicated that while timing performance in the visual learning condition depended on motor and memory capacity, sensorimotor learning facilitated an accurate representation of time independently of individual differences in motor and memory skill. Overall, our findings support the idea that action helps children to construct an independent and flexible representation of time, which leads to coupled sensorimotor coding for action and time.

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.

Explicit and implicit timing in aging

Explicit and implicit measures of timing were compared between young and older participants. In both tasks, participants were initially familiarized with a reference interval by responding to the second of two beeps separated by a fixed interval. During the subsequent testing phase, this inter-stimulus interval was variable. In the explicit task, participants were instructed to judge interval duration, whereas in the implicit task they were told to respond as quickly as possible to the second beep. Cognitive abilities were assessed with neuropsychological tests. Results showed that in both explicit and implicit timing tasks, temporal performance peaked around the reference interval and did not differ between young and older participants. This indicates an accurate representation of duration that did not decline with normal aging. However, some age-related differences were observed in performance depending on the task used. In the explicit timing task, the variability of duration judgments was greater in older than young participants, though this was directly related to older participants' lower attentional capacity. In the implicit timing task, young participants' reaction times (RTs) were slower to targets appearing either earlier or later than the trained interval. Conversely, while older participants RTs were also slowed by early targets, their RTs to late targets were as fast as those to targets appearing at the trained interval. We hypothesize that with age, and irrespective of cognitive ability, there is increasing reliance on temporal information conveyed by the probability of target appearance as a function of elapsing time ("hazard function") than that conveyed by the statistical likelihood of previously experienced temporal associations.

Activity in perceptual classification networks as a basis for human subjective time perception

Despite being a fundamental dimension of experience, how the human brain generates the perception of time remains unknown. Here, we provide a novel explanation for how human time perception might be accomplished, based on non-temporal perceptual classification processes. To demonstrate this proposal, we build an artificial neural system centred on a feed-forward image classification network, functionally similar to human visual processing. In this system, input videos of natural scenes drive changes in network activation, and accumulation of salient changes in activation are used to estimate duration. Estimates produced by this system match human reports made about the same videos, replicating key qualitative biases, including differentiating between scenes of walking around a busy city or sitting in a cafe or office. Our approach provides a working model of duration perception from stimulus to estimation and presents a new direction for examining the foundations of this central aspect of human experience.

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.

Time and distance estimation in children using an egocentric navigation task

Navigation crucially depends on the capability to estimate time elapsed and distance covered during movement. From adults it is known that magnitude estimation is subject to characteristic biases. Most intriguing is the regression effect (central tendency), whose strength depends on the stimulus distribution (i.e. stimulus range), a second characteristic of magnitude estimation known as range effect. We examined regression and range effects for time and distance estimation in eleven-year-olds and young adults, using an egocentric virtual navigation task. Regression effects were stronger for distance compared to time and depended on stimulus range. These effects were more pronounced in children compared to adults due to a more heterogeneous performance among the children. Few children showed veridical estimations similar to adults; most children, however, performed less accurate displaying stronger regression effects. Our findings suggest that children use magnitude processing strategies similar to adults, but it seems that these are not yet fully developed in all eleven-year-olds and are further refined throughout adolescence.

Videos look faster as children grow up: Sense of speed and impulsivity throughout primary school

Previous research has documented systematic biases when adult observers judge the original speed of real-life video clips. What does the unfolding of events in videos-an increasingly pervasive "substitute reality"-look like as children grow up? The current study investigated the sense of speed during childhood and the relation with a number of performance and personality indexes. A group of 142 children aged 6-10 years adjusted the speed of video clips representing various scenes until reaching the apparent right speed. We found a tendency to underestimate speed; on average, videos played at their original speed were considered to be too slow. This tendency was larger in younger children and decreased with age (-3.16%/year). Uncertainty in judging video speed also decreased over the same age period (-10.79%/year). Children then performed a simple visuomotor task requiring response control, which revealed high accuracy and, in older children, faster responses. Children were also assessed for impulsivity/inattention and visuomotor habits through parents' questionnaires. When all variables were considered together, age and video game playing stood out as the only significant predictors of speed biases, both associated with an increase in apparent video speed. Thus, this study provides evidence of a change in the sense of speed during the primary school period, possibly involving the progressive overriding of a slow motion prior and/or the protracted calibration of perceptual mechanisms for speed constancy. The sense of speed, however, did not seem to be influenced by impulsivity traits in the population considered.

A Mental Timeline for Duration From the Age of 5 Years Old

Both time and number can be represented in spatial terms. While their representation in terms of spatial magnitude (distance or size) might be innate, their representation in terms of spatial position (left/right or up/down) is acquired. In Western culture, the mental timeline represents past/future events or short/long duration on the left/right sides of space, respectively. We conducted two developmental studies to pinpoint the age at which the mental timeline for duration begins to be acquired. Children (aged 5–6, 8, or 10 years old) and adults performed temporal bisection tasks in which relative spatial position (left/right) was manipulated by either arrow direction (Experiment 1) and/or lateralized stimulus location (Experiments 1 and 2). Results first confirmed previous findings that the symbolic representation of spatial position conveyed by arrow stimuli influences the perception of duration in older children. Both 8 and 10 year olds judged the duration of leftward arrows to be shorter than that of rightward arrows. We also showed for the first time that as long as position is manipulated in a non-symbolic way by the visual eccentricity of the stimuli, then even 5–6 year olds’ perception of duration is influenced by spatial position. These children judged the duration of left-lateralized stimuli to be shorter than that of either right-lateralized or centrally located stimuli. These data are consistent with the use of a mental timeline for stimulus duration from the age of 5 years old, with short duration being represented on the left side of space and long duration on the right. Nevertheless, the way in which left and right were manipulated determined the age at which spatial position influenced duration judgment: physical spatial location influenced duration perception from the age of 5 years old whereas arrow direction influenced it from the age of 8. This age-related dissociation may reflect distinct developmental trajectories of automatic versus voluntary spatial attentional mechanisms and, more generally highlights the importance of accounting for attentional ability when interpreting results of duration judgment tasks.

Effect of the Symbolic Meaning of Speed on the Perceived Duration of Children and Adults

The present study investigated how the symbolic meaning of speed affects time perception in children and adults. We employed a time reproduction task in which participants were asked to reproduce temporal intervals previously presented. In Experiment 1, 45 primary school children and 22 university students performed a time reproduction task with cars (meaning of fastness) and trucks (meaning of slowness) presented for 11 and 21 s in static and moving conditions. Results showed that young children under-reproduced the duration more than the older children and adults, especially when the stimulus presented was a car. Moreover, participants under-reproduced moving stimuli compared to static one. In Experiment 2, we tested 289 participants who were divided into nine different age groups according to their school class: five from primary school, three from Junior High, and one from the university. Participants performed a time reproduction task with a motorbike (meaning of fastness) or a bicycle (meaning of slowness) under static and moving conditions for 11, 21, and 36 s. The results confirmed the effects of symbolic meaning of speed on children’s time perception and showed that vehicles that evoked the idea of fastness were under-reproduced compared to stimuli evoking the idea of slowness.

Time processing impairments in preschoolers at risk of developing difficulties in mathematics

The occurrence of time processing problems in individuals with Development Dyscalculia (DD) has favored the view of a general magnitude system devoted to both numerical and temporal information. Yet, this scenario has been partially challenged by studies indicating that time difficulties can be attributed to poor calculation or counting skills, which can support reasoning on time in school-aged children and adults. Here, we tackle this debate by exploring the performance of young children before they fully develop the symbolic number system. Preschoolers at risk of developing DD were compared with typically developing children in a series of tasks investigating time processing and in their 'sense of time', evaluated by parents and teachers. Results yielded a poorer performance in time reproduction of 5-second intervals and in time discrimination, as well as a weaker 'sense of time', in children at risk of DD. These findings provide evidence of a common magnitude system that would be responsible for deficits in both numerical and temporal domains, already at early stages of life.

A Brief History of “The Psychology of Time Perception”

Basic mechanisms of interval timing and associative learning are shared by many animal species, and develop quickly in early life, particularly across infancy, and childhood. Indeed, John Wearden in his book “The Psychology of Time Perception”, which is based on decades of his own research with colleagues, and which our commentary serves to primarily review, has been instrumental in implementing animal models and methods in children and adults, and has revealed important similarities (and differences) between human timing (and that of animals) when considered within the context of scalar timing theory. These seminal studies provide a firm foundation upon which the contemporary multifaceted field of timing and time perception has since advanced. The contents of the book are arguably one piece of a larger puzzle, and as Wearden cautions, “The reader is warned that my own contribution to the field has been exaggerated here, but if you are not interested in your own work, why would anyone else be?” Surely there will be many interested readers, however the book is noticeably lacking in it neurobiological perspective. The mind (however it is conceived) needs a brain (even if behaviorists tend to say “the brain behaves”, and most neuroscientists currently have a tenuous grasp on the neural mechanisms of temporal cognition), and to truly understand the psychology of time, brain and behavior must go hand in hand regardless of the twists, turns, and detours along the way.

Isochronous Sequential Presentation Helps Children Orient Their Attention in Time

Knowing when an event is likely to occur allows attentional resources to be oriented toward that moment in time, enhancing processing of the event. We previously found that children (mean age 11 years) are unable to use endogenous temporal cues to orient attention in time, despite being able to use endogenous spatial cues (arrows) to orient attention in space. Arrow cues, however, may have proved beneficial by engaging exogenous (automatic), as well as endogenous (voluntary), orienting mechanisms. We therefore conducted two studies in which the exogenous properties of visual temporal cues were increased, to examine whether this helped children orient their attention in time. In the first study, the location of an imperative target was predicted by the direction of a left or right spatial arrow cue while its onset was predicted by the relative duration of a short or long temporal cue. To minimize the influence of rhythmic entrainment in the temporal condition, the foreperiod (500 ms/1100 ms) was deliberately chosen so as not to precisely match the duration of the temporal cue (100 ms/400 ms). Targets appeared either at cued locations/onset times (valid trials) or at unexpected locations/onset times (invalid trials). Adults’ response times were significantly slower for invalid versus valid trials, in both spatial and temporal domains. Despite being slowed by invalid spatial cues, children (mean age 10.7 years) were unperturbed by invalid temporal cues, suggesting that these duration-based temporal cues did not help them orient attention in time. In the second study, we enhanced the exogenous properties of temporal cues further, by presenting multiple temporal cues in an isochronous (rhythmic) sequence. Again, to minimize automatic entrainment, target onset did not match the isochronous interval. Children (mean age 11.4 years), as well as adults, were now significantly slowed by invalid cues in both the temporal and spatial dimension. The sequential, as opposed to single, presentation of temporal cues therefore helped children to orient their attention in time. We suggest that the exogenous properties of sequential presentation provide a temporal scaffold that supports the additional attentional and mnemonic requirements of temporal, as compared to spatial, processing.

Distinct developmental trajectories for explicit and implicit timing

Adults and children aged 5 and 8years were given explicit and implicit timing tasks. These tasks were based on the same temporal representation (the temporal interval between two signals), but in the explicit task participants received overt instructions to judge the duration of the interval, whereas in the implicit task they did not receive any temporal instructions and were asked only to press as quickly as possible after the second signal. In addition, participants' cognitive capacities were assessed with different neuropsychological tests. The results showed that temporal variability (i.e., the spread of performance around the reference interval) decreased as a function of age in the explicit task, being higher in the 5-year-olds than in the 8-year-olds and adults. The higher variability in the youngest children was directly linked to their limited cognitive capacity. By contrast, temporal variability in the implicit timing task remained constant across the different age groups and was unrelated to cognitive capacity. Processing of time, therefore, was independent of age in the implicit task but changed with age in the explicit task, thereby demonstrating distinct developmental trajectories for explicit and implicit timing.