Developmental changes in time estimation: comparing childhood and old age

Young adults and multisensory time perception: Visual and auditory pathways in comparison

The brain continuously encodes information about time, but how sensorial channels interact to achieve a stable representation of such ubiquitous information still needs to be determined. According to recent research, children show a potential interference in multisensory conditions, leading to a trade-off between two senses (sight and audition) when considering time-perception tasks. This study aimed to examine how healthy young adults behave when performing a time-perception task. In Experiment 1, we tested the effects of temporary sensory deprivation on both visual and auditory senses in a group of young adults. In Experiment 2, we compared the temporal performances of young adults in the auditory modality with those of two samples of children (sighted and sighted but blindfolded) selected from a previous study. Statistically significant results emerged when comparing the two pathways: young adults overestimated and showed a higher sensitivity to time in the auditory modality compared to the visual modality. Restricting visual and auditory input did not affect their time sensitivity. Moreover, children were more accurate at estimating time than young adults after a transient visual deprivation. This implies that as we mature, sensory deprivation does not constitute a benefit to time perception, and supports the hypothesis of a calibration process between senses with age. However, more research is needed to determine how this calibration process affects the developmental trajectories of time perception.

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.

On the interplay of temporal resolution power and spatial suppression in their prediction of psychometric intelligence

As a measure of the brain’s temporal fine-tuning capacity, temporal resolution power (TRP) explained repeatedly a substantial amount of variance in psychometric intelligence. Recently, spatial suppression, referred to as the increasing difficulty in quickly perceiving motion direction as the size of the moving stimulus increases, has attracted particular attention, when it was found to be positively related to psychometric intelligence. Due to the conceptual similarities of TRP and spatial suppression, the present study investigated their mutual interplay in the relation to psychometric intelligence in 273 young adults to better understand the reasons for these relationships. As in previous studies, psychometric intelligence was positively related to a latent variable representing TRP but, in contrast to previous reports, negatively to latent and manifest measures of spatial suppression. In a combined structural equation model, TRP still explained a substantial amount of variance in psychometric intelligence while the negative relation between spatial suppression and intelligence was completely explained by TRP. Thus, our findings confirmed TRP to be a robust predictor of psychometric intelligence but challenged the assumption of spatial suppression as a representation of general information processing efficiency as reflected in psychometric intelligence. Possible reasons for the contradictory findings on the relation between spatial suppression and psychometric intelligence are discussed.

Explicit and implicit timing in older adults: Dissociable associations with age and cognitive decline

This study aimed to test two common explanations for the general finding of age-related changes in the performance of timing tasks within the millisecond-to-second range intervals. The first explanation is that older adults have a real difficulty in temporal processing as compared to younger adults. The second explanation is that older adults perform poorly on timing tasks because of their reduced cognitive control functions. These explanations have been mostly contrasted in explicit timing tasks that overtly require participants to process interval durations. Fewer studies have instead focused on implicit timing tasks, where no explicit instructions to process time are provided. Moreover, the investigation of both explicit and implicit timing in older adults has been restricted so far to healthy older participants. Here, a large sample (N = 85) comprising not only healthy but also pathological older adults completed explicit (time bisection) and implicit (foreperiod) timing tasks within a single session. Participants’ age and cognitive decline, measured with the Mini-Mental State Examination (MMSE), were used as continuous variables to explain performance on explicit and implicit timing tasks. Results for the explicit timing task showed a flatter psychometric curve with increasing age or decreasing MMSE scores, pointing to a deficit at the level of cognitive control functions rather than of temporal processing. By contrast, for the implicit timing task, a decrease in the MMSE scores was associated with a reduced foreperiod effect, an index of implicit time processing. Overall, these findings extend previous studies on explicit and implicit timing in healthy aged samples by dissociating between age and cognitive decline (in the normal-to-pathological continuum) in older adults.

Older adults preserve accuracy but not precision in explicit and implicit rhythmic timing

Aging brings with it several forms of neurophysiological and cognitive deterioration, but whether a decline in temporal processing is part of the aging process is unclear. The current study investigated whether this timing deficit has a cause independent of those of memory and attention using rhythmic stimuli that reduce the demand for these higher cognitive functions. In Study 1, participants took part in two rhythmic timing tasks: explicit and implicit. Participants had to distinguish regular from irregular sequences while processing temporal information explicitly or implicitly. Results showed that while the accuracy in the implicit timing task was preserved, older adults had more noise in their performance in the explicit and implicit tasks. In Study 2, participants took part in a dual-implicit task to explore whether the performance of temporal tasks differed with increasing task difficulty. We found that increasing task difficulty magnifies age-related differences.

Virtual Embodiment Using 180° Stereoscopic Video

One of the most exciting possibilities of virtual reality is inducing in participants the illusion of owning a virtual body. This has become an established methodological paradigm allowing the study of the psychological and neural correlates of various scenarios that are impossible in the real world, such as gender or age switching. Thus far, full-body ownership illusions have been implemented by using real-time body tracking and avatars based on computer-generated imagery (CGI). We propose an alternative technique to induce perceived ownership over a (photorealistic) virtual body using 180° stereoscopic video, synchronous touch, and narration. We describe the technical components of our novel technique and an example implementation as part of a science-art project that enables participants to experience virtual bodies of different ages, and present the results of an experimental evaluation study based on this experience. Consistent with previous virtual embodiment studies using CGI-based techniques, we found that participants accept a photorealistic virtual body as their own irrespective of its appearance as indicated by similar ratings of the strength of body ownership over a virtual body of a child versus an adult. We further show that our novel technique can alter participants' cognition in accordance with the characteristics of their virtual body. Specifically, young adult participants who were embodied in the virtual body of a child significantly overestimated the duration of the virtual reality experience compared to a control group who was embodied in a virtual body of their own age. This finding corresponds to chronological age differences in time estimations and extends previous research on virtual child embodiment. Overall, these findings provide initial evidence for the potential of our novel technique to create photorealistic embodiment experiences with comparable psychological effects as have been found using CGI-based techniques while reducing the costs and technical complexity in the production and application of virtual body ownership illusions.

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.

Time perception and autistic spectrum condition: A systematic review

Problems with timing and time perception have been suggested as key characteristics of autism spectrum condition (ASC). Studies and personal accounts from clinicians, parents, caregivers, and self‐reports from autistic people themselves often refer to problems with time. Although a number of empirical studies have examined aspects relating to time in autistic individuals, there remains no clear consensus on whether or how timing mechanisms may be affected in autism. A key reason for this lack of clarity is the wide range of timing processes that exist and subsequently the wide range of methodologies, research paradigms, and samples that time‐based studies have used with autism populations. In order to summarize and organize the available literature on this issue, a systematic review was conducted. Five electronic databases were consulted. From an initial 597 records (after duplicates were removed), 45 papers were selected and reviewed. The studies are reviewed within different sections based on the different types of timing ability that have been explored in the neurotypical (NT) population: time sensitivity, interval timing, and higher‐order time perception. Within each section cognitive models, methodologies, possible clinical implications, and research results are discussed. The results show different consistency across studies between the three types of timing ability. The highest consistency of results showing atypical time perception abilities is found in high‐level time perception studies. It remains unclear if autism is characterized by a fundamental time perception impairment. Suggestions for future research are discussed. Autism Res 2019, 12: 1440–1462. © 2019 International Society for Autism Research, Wiley Periodicals, Inc.

Lay Summary

This systematic review examines the different types of timing and time perception behavior that have been investigated in autism. Overall, there are a number of studies that show differences between autistic and non‐autistic individuals, but some studies do not find such differences. Group differences are more consistent across studies using complex tasks rather than simpler more fundamental timing tasks. We suggest that experiments across a range of timing tasks would be fruitful to address gaps in our knowledge.

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.

Multiple Time Intervals of Visual Events Are Represented as Discrete Items in Working Memory

Previous studies on time perception and temporal memory have focused primarily on single time intervals; it is still unclear how multiple time intervals are perceived and maintained in working memory. In the present study, using Sternberg's item recognition task, we compared the working memory of multiple items with different time intervals and visual textures, for sub- and supra-second ranges, and investigated the characteristics of working memory representation in the framework of the signal detection theory. In Experiments 1-3, gratings with different spatial frequencies and time intervals were sequentially presented as study items, followed by another grating as a probe. Participants determined whether the probe matched one of the study gratings, in either the temporal dimension or in the visual dimension. The results exhibited typical working memory characteristics such as the effects of memory load, serial position, and similarity between probe and study gratings, similarly, to the time intervals and visual textures. However, there were some differences between the two conditions. Specifically, the recency effect for time intervals was smaller, or even absent, as compared to that for visual textures. Further, as compared with visual textures, sub-second intervals were more likely to be judged as remembered in working memory. In addition, we found interactions between visual texture memory and time interval memory, and such visual-interval binding differed between sub- and supra-second ranges. Our results indicate that multiple time intervals are stored as discrete items in working memory, similarly, to visual texture memory, but the former might be more susceptible to decay than the latter. The differences in the binding between sub- and supra-second ranges imply that working memory for sub- and supra-second ranges may differ in the relatively higher decision stage.

Using Time Perception to Explore Implicit Sensitivity to Emotional Stimuli in Autism Spectrum Disorder

Establishing whether implicit responses to emotional cues are intact in autism spectrum disorder (ASD) is fundamental to ascertaining why their emotional understanding is compromised. We used a temporal bisection task to assess for responsiveness to face and wildlife images that varied in emotional salience. There were no significant differences between an adult ASD and comparison group, with both showing implicit overestimation of emotional stimuli. Further, there was no correlation between overestimation of emotional stimuli and autistic traits in undergraduate students. These data do not suggest a fundamental insensitivity to the arousing content of emotional images in ASD, or in individuals with a high degree of autistic traits. The findings have implications for understanding how emotional stimuli are processed in ASD.

Executive processes and timing: Comparing timing with and without reference memory

Temporal perception is influenced by executive function. However, performance on different temporal tasks is often associated with different executive functions. This study examined whether using reference memory during a task influenced how performance was associated with executive resources. Participants completed temporal generalisation and bisection tasks, in their normal versions involving reference memory and in episodic versions without reference memory. Each timing task had two difficulty levels: easy and hard. Correlations between performance on these tasks and measures of executive function (updating, inhibition, task switching, and access to semantic memory) were assessed. Accuracy on the temporal generalisation task was correlated with memory access for all versions of the task. Updating correlated with accuracy only for the reference memory-based version of the task. Temporal bisection performance presented a different pattern of correlations. The bisection point was negatively correlated with inhibition scores, except for the easy episodic condition. The Weber ratio, considered a measure of temporal sensitivity, was negatively correlated with memory access only in the hard episodic condition. Together, the findings suggest that previous models of generalisation and bisection may not accurately reflect the underlying cognitive processes involved in the tasks.

Is the Growth of Subjective Time in Humans a Linear or Nonlinear Function of Real Time?

The difficulties of deciding whether subjective time grows as a linear or nonlinear function of real time are discussed, and two experiments are presented to address this question. In Experiment 1, people received a 10-s standard duration and then had to judge what proportion other durations (ranging from 1 to 10 s) were of the standard. Counting was prevented by a concurrent task. The relation between judged and actual proportions was linear. In Experiment 2, people were required to average together three tone durations (mean duration 600 ms) and to judge whether subsequently presented comparisons were or were not the average. The spacing of the tone durations had no effect on judgements, suggesting a linear underlying time scale.

More is not necessarily better: Examining the nature of the temporal reference memory component in timing

Three experiments compared the timing performance of humans on a modified temporal generalization task with 1, 3, or 5 presentations of the standard duration. In all three experiments subjects received presentations of a standard duration at the beginning of a trial block and then had to judge whether each of a number of comparison stimuli was or was not the standard. The duration of the standard changed between blocks. The three experiments varied the experimental design (between or within subjects), task difficulty (how closely the comparison stimuli were spaced around the standards), and presence or absence of feedback on performance accuracy. Number of presentations of the standard never affected the proportion of identifications of the standard when it was presented, nor other features of the temporal generalization gradients observed. The implications for the operation of reference memories within the scalar timing system were explored via models that made different assumptions about how the individual presentations of the standard were stored and used.

Episodic temporal generalization: A developmental study

Groups of 5-year-olds, 10-year-olds, and adults completed either an episodic temporal generalization task, in which no stimuli were repeated, or a repeated standard temporal generalization task, in which there was a fixed standard that was repeated on every trial. Significant developmental improvements were found on both tasks. In both tasks, gradients of performance over two different stimulus ranges superimposed well when plotted on the same relative scale. Performance was similar for the adults and 10-year-olds across tasks, but the 5-year-olds performed better on the repeated standard task. These findings suggest that perceptual processes are a source of scalar variability in timing, and that there are developmental changes in levels of such variability.

The Effect of Feedback on Timing in Children and Adults: The Temporal Generalization Task

Children aged 5 and 8 years and adults were tested on a temporal generalization task with a standard duration of 600 ms in a condition with or without corrective feedback. In all conditions, the participants produced orderly temporal generalization gradients, although these were flatter in the younger children, especially in the no-feedback condition. Nevertheless, the results show that the feedback increased the steepness of the generalization gradient in all age groups and in a greater extent in the younger children. Our clock-based model suggested that feedback reduces the variability of the memory representation of the standard duration but also the probability of random responses in the 5-year-olds.

Testing the representation of time in reference memory in the bisection and the generalization task: The utility of a developmental approach

This study examined the effect of the variability of representation of durations in reference memory on temporal discrimination performance in children aged 5 and 8 years as well as in adults using a bisection (Experiment 1) and a generalization task (Experiment 2). In each task, the participants were familiarized before the blocks of tested trials with either the same referent duration values (fixed condition) or a distribution of referent duration values, with a mean equal to the referent durations used in the fixed condition and a .20 coefficient of variation (variable condition). The results showed that the sensitivity to duration was lower in the variable than in the fixed condition in the children and, to a lesser extent, in the adults. The modelling of the data indicated that this effect was due to the increase in the variability of the representation of durations in reference memory, but also to changes in the decisional processes.

Sensorimotor synchronization across the life span

The present study investigates the contribution of general processing resources as well as other more specific factors to the life-span development of sensorimotor synchronization and its component processes. Within a synchronization tapping paradigm, a group of 286 participants, 6 to 88 years of age, were asked to synchronize finger taps with sequences of auditory signals. The auditory signals were given either isochronously with short or long interstimulus intervals in a regular condition or in a more demanding condition with alternating short and long intervals. The results provided the first direct life-span evidence showing that performance in these tasks improves substantially during childhood until about late teens, and thereon remains at least relatively stable until old age. This pattern of life-span age gradient holds for measures of different component processes of sensorimotor synchronization, such as basic timekeeping and error correction processes. The findings are not in line with simple general factor accounts of development. They rather suggest a more complex interaction between general resources and other specific factors in the life-span development of different components of sensorimotor synchronization.

Central tendency effects in time interval reproduction in autism

Central tendency, the tendency of judgements of quantities (lengths, durations etc.) to gravitate towards their mean, is one of the most robust perceptual effects. A Bayesian account has recently suggested that central tendency reflects the integration of noisy sensory estimates with prior knowledge representations of a mean stimulus, serving to improve performance. The process is flexible, so prior knowledge is weighted more heavily when sensory estimates are imprecise, requiring more integration to reduce noise. In this study we measure central tendency in autism to evaluate a recent theoretical hypothesis suggesting that autistic perception relies less on prior knowledge representations than typical perception. If true, autistic children should show reduced central tendency than theoretically predicted from their temporal resolution. We tested autistic and age- and ability-matched typical children in two child-friendly tasks: (1) a time interval reproduction task, measuring central tendency in the temporal domain; and (2) a time discrimination task, assessing temporal resolution. Central tendency reduced with age in typical development, while temporal resolution improved. Autistic children performed far worse in temporal discrimination than the matched controls. Computational simulations suggested that central tendency was much less in autistic children than predicted by theoretical modelling, given their poor temporal resolution.

Cognitive Aging and Time Perception: Roles of Bayesian Optimization and Degeneracy

This review outlines the basic psychological and neurobiological processes associated with age-related distortions in timing and time perception in the hundredths of milliseconds-to-minutes range. The difficulty in separating indirect effects of impairments in attention and memory from direct effects on timing mechanisms is addressed. The main premise is that normal aging is commonly associated with increased noise and temporal uncertainty as a result of impairments in attention and memory as well as the possible reduction in the accuracy and precision of a central timing mechanism supported by dopamine-glutamate interactions in cortico-striatal circuits. Pertinent to these findings, potential interventions that may reduce the likelihood of observing age-related declines in timing are discussed. Bayesian optimization models are able to account for the adaptive changes observed in time perception by assuming that older adults are more likely to base their temporal judgments on statistical inferences derived from multiple trials than on a single trial's clock reading, which is more susceptible to distortion. We propose that the timing functions assigned to the age-sensitive fronto-striatal network can be subserved by other neural networks typically associated with finely-tuned perceptuo-motor adjustments, through degeneracy principles (different structures serving a common function).

Using a pictorial timeline to assess age-related changes in time estimation of daily events

How do older adults compare with younger adults in estimating the timing of daily events, such as heating a meal, keeping an appointment, or taking medication? In Experiment 1, we used a pictorial timeline method to examine age-related changes in how people estimate the time involved in daily events. We also conducted a spatial processing task to control for possible age-related bias in spatial processing. Findings showed that older adults projected smaller windows of time on the timeline to represent the duration of events than did younger adults, which indicates that older adults underestimate time duration. However, older adults also projected smaller windows in spatial task, which creates ambiguity in interpreting the reduced duration estimates among older adults. In Experiment 2, we administered an improved timeline task and spatial task that were comparable in difficulty between age groups and used defined endpoints of the reference line. Consistent with findings from Experiment 1, older adults projected a smaller time window than their younger counterparts, whereas the two age groups showed no differences in estimating spatial distances in the improved spatial experiment. Taken together, our findings suggest that older adults make shorter estimates of the duration of an event than younger adults, and that these age differences are due to age-related differences in orientation to time rather than to a general bias in spatial processing.

Cognitive abilities required in time judgment depending on the temporal tasks used: A comparison of children and adults

The aim of this study was to examine age-related differences in time judgments during childhood as a function of the temporal task used. Children aged 5 and 8 years, as well as adults, were submitted to 3 temporal tasks (bisection, generalization and reproduction) with short (0.4/0.8 s) and long durations (8/16 s). Furthermore, their cognitive capacities in terms of working memory, attentional control, and processing speed were assessed by a wide battery of neuropsychological tests. The results showed that the age-related differences in time judgment were greater in the reproduction task than in the temporal discrimination tasks. This task was indeed more demanding in terms of working memory and information processing speed. In addition, the bisection task appeared to be easier for children than the generalization task, whereas these 2 tasks were similar for the adults, although the generalization task required more attention to be paid to the processing of durations. Our study thus demonstrates that it is important to understand the different cognitive processes involved in time judgment as a function of the temporal tasks used before venturing to draw conclusions about the development of time perception capabilities.

Age-Related Differences in Speech Rate Perception Do Not Necessarily Entail Age-Related Differences in Speech Rate Use

PURPOSE

A new literature has suggested that speech rate can influence the parsing of words quite strongly in speech. The purpose of this study was to investigate differences between younger adults and older adults in the use of context speech rate in word segmentation, given that older adults perceive timing information differently from younger ones.

METHOD

Younger (18-25 years) and older (55-65 years) adults performed a sentence transcription task for sentences that varied in speech rate context (i.e., distal speech rate) and a syntactic cue to the presence of a word boundary.

RESULTS

There were no differences between younger and older adults in their use of the distal speech rate cue to word segmentation.

CONCLUSIONS

The differences previously documented between younger and older adults in their perception of speech rate cues do not necessarily translate to older adults' use of those cues. Older adults' difficulties with compressed speech may arise from problems broader than just speech rate alone.

Learning the language of time: Children's acquisition of duration words

Children use time words like minute and hour early in development, but take years to acquire their precise meanings. Here we investigate whether children assign meaning to these early usages, and if so, how. To do this, we test their interpretation of seven time words: second, minute, hour, day, week, month, and year. We find that preschoolers infer the orderings of time words (e.g., hour>minute), but have little to no knowledge of the absolute durations they encode. Knowledge of absolute duration is learned much later in development - many years after children first start using time words in speech - and in many children does not emerge until they have acquired formal definitions for the words. We conclude that associating words with the perception of duration does not come naturally to children, and that early intuitive meanings of time words are instead rooted in relative orderings, which children may infer from their use in speech.

In search of the internal structure of the processes underlying interval timing in the sub-second and the second range: a confirmatory factor analysis approach

One of the earliest accounts of duration perception by Karl von Vierordt implied a common process underlying the timing of intervals in the sub-second and the second range. To date, there are two major explanatory approaches for the timing of brief intervals: the Common Timing Hypothesis and the Distinct Timing Hypothesis. While the common timing hypothesis also proceeds from a unitary timing process, the distinct timing hypothesis suggests two dissociable, independent mechanisms for the timing of intervals in the sub-second and the second range, respectively. In the present paper, we introduce confirmatory factor analysis (CFA) to elucidate the internal structure of interval timing in the sub-second and the second range. Our results indicate that the assumption of two mechanisms underlying the processing of intervals in the second and the sub-second range might be more appropriate than the assumption of a unitary timing mechanism. In contrast to the basic assumption of the distinct timing hypothesis, however, these two timing mechanisms are closely associated with each other and share 77% of common variance. This finding suggests either a strong functional relationship between the two timing mechanisms or a hierarchically organized internal structure. Findings are discussed in the light of existing psychophysical and neurophysiological data.

A new self-report quality of life questionnaire for children with neuromuscular disorders: presentation of the instrument, rationale for its development, and some preliminary results

Improvement of quality of life in neuromuscular disorders is a primary objective, both in management of affected children and in the context of therapeutic trials. Quality of life is a subjective concept and it is crucial to gather information directly from patients. We created the SOLE Questionnaire for NMDs, a new instrument designed to investigate quality of life in children with neuromuscular disorders, and tested it in a study population of 78 patients and in 81 healthy children aged 5 to 13 years. The SOLE Questionnaire, characterized by a visual and neutral approach, was well received, practical, rapid to administer, and able to discriminate between patients and controls. We also confirmed the presence of disagreement about children's quality of life between children and their parents. We suggest that our new approach could help to improve understanding of quality of life in children with neuromuscular disorders.

Development of time sensitivity and information processing speed

The aim of this study was to examine whether age-related changes in the speed of information processing are the best predictors of the increase in sensitivity to time throughout childhood. Children aged 5 and 8 years old, as well adults, were given two temporal bisection tasks, one with short (0.5/1-s) and the other with longer (4/8-s) anchor durations. In addition, the participants' scores on different neuropsychological tests assessing both information processing speed and other dimensions of cognitive control (short-term memory, working memory, selective attention) were calculated. The results showed that the best predictor of individual variances in sensitivity to time was information processing speed, although working memory also accounted for some of the individual differences in time sensitivity, albeit to a lesser extent. In sum, the faster the information processing speed of the participants, the higher their sensitivity to time was. These results are discussed in the light of the idea that the development of temporal capacities has its roots in the maturation of the dynamic functioning of the brain.

Effects of motion on time perception

To investigate the effect of motion on time perception, participants were asked to perform either a temporal discrimination task or a temporal generalization task while running or standing still on a treadmill. In the temporal discrimination (bisection) task, 10 participants were exposed to two anchor stimuli, a 300-ms Short tone and a 700-ms Long tone, and then classified intermediate durations in terms of their similarity to the anchors. In the temporal generalization task, 10 other participants were exposed to a standard duration (500ms) and then judged whether or not a series of comparison-durations, ranging from 300ms to 700ms, had the same duration as the standard. The results showed that in the temporal bisection task the participants produced more "Long" responses under the dual-task condition (temporal judgments+running) than under the single-task condition (temporal judgments only). In the temporal generalization task, accuracy in the temporal judgments was lower in the dual-task condition than the single-task condition. These results are discussed in the light of dual-task paradigm and of the Scalar Expectancy Theory (SET).

Explaining between-group differences in performance on timing tasks

The article discusses interpretation of between-group differences in performance on timing tasks. First, it is shown that differences in internal clock “pacemaker speed” cannot normally be used as a coherent explanation of obtained effects, even if such differences in pacemaker speed exist. Secondly, it is shown how, in theory, modelling of performance on commonly used timing tasks like bisection and temporal generalization can illuminate between-group effects. Thirdly, the article discusses some examples of such modelling from published work and shows how some between-group differences—for example, between children of different ages, or between patients and controls—have been explained. Finally, some ambiguities in modelling are discussed—for example, the fact that different explanations of differences in performance on timing tasks between groups may be difficult or impossible to distinguish in practice.

Time perception in children: a neurodevelopmental approach

In this review, we discuss behavioral studies on time perception in healthy children that suggest the existence of a primitive "sense" of time in infants as well as research that has revealed the changes in time judgments that occur throughout childhood. Moreover, a distinction is made between implicit and explicit time judgments in order to take account of the different types of temporal judgments that emerge across ages. On the basis of both the neurobiological model of the internal clock proposed by Matell and Meck (2000), and of results of imaging studies in human adults, we then try to identify which of the neural structures underlying this primitive sense of time mature faster and which mature more slowly in order to explain the age-related variance in time judgments. To this end, we also present the small number of timing studies conducted among typically and non-typically developing children that have used functional magnetic resonance imaging (fMRI) as well as those that have assessed the cognitive capacities of such children on the basis of various neuropsychological tests.

Development of time sensitivity: duration ratios in time bisection

This study investigated the development of children's abilities to discriminate durations as a function of their ratio and examined whether the ability to discriminate durations that differed by a very difficult ratio is related to the development of attention capacities. Children aged 5 and 8 years, as well as adults, performed a series of temporal bisection tasks with a ratio between the short and the long anchor duration that was changed to control the difficulty of the task (5:6, 2:3, and 1:2) in two duration ranges (<1 s and >3 s). In addition, they completed neuropsychological tests in order to assess their short-term memory, working memory, and visual attention abilities. The results showed that, at ratios of 2:3 and 1:2, most participants were able to discriminate the anchor durations in bisection. However, their sensitivity to time improved, whatever the duration range, both as the distance between the anchor durations increased and with increasing age. For the smallest duration ratio (5:6), few of the children were able to discriminate the anchor durations in the bisection task in comparison to adults. Hierarchical regression analyses performed on the neuropsychological tests revealed that, for the 2:3 ratio between anchor durations, the participants' visual attention scores explained a large part of the variance in time sensitivity. The children's lower temporal sensitivity was probably due to their limited visual attention abilities, thus explaining the difficulty they experienced in discriminating very close durations (5:6).

Auditory and visual differences in time perception? An investigation from a developmental perspective with neuropsychological tests

Adults and children (5- and 8-year-olds) performed a temporal bisection task with either auditory or visual signals and either a short (0.5-1.0s) or long (4.0-8.0s) duration range. Their working memory and attentional capacities were assessed by a series of neuropsychological tests administered in both the auditory and visual modalities. Results showed an age-related improvement in the ability to discriminate time regardless of the sensory modality and duration. However, this improvement was seen to occur more quickly for auditory signals than for visual signals and for short durations rather than for long durations. The younger children exhibited the poorest ability to discriminate time for long durations presented in the visual modality. Statistical analyses of the neuropsychological scores revealed that an increase in working memory and attentional capacities in the visuospatial modality was the best predictor of age-related changes in temporal bisection performance for both visual and auditory stimuli. In addition, the poorer time sensitivity for visual stimuli than for auditory stimuli, especially in the younger children, was explained by the fact that the temporal processing of visual stimuli requires more executive attention than that of auditory stimuli.

Modality Effects in Memory for Basic Stimulus Attributes: A Temporal and Nontemporal Comparison

Previous research suggests that there are significant differences in the operation of reference memory for stimuli of different modalities, with visual temporal entries appearing to be more durable than auditory entries (Ogden, Wearden, & Jones, 2008, 2010). Ogden et al. (2008, 2010) demonstrated that when participants were required to store multiple auditory temporal standards over a period of delay there was significant systematic interference to the representation of the standard characterized by shifts in the location of peak responding. No such performance deterioration was observed when multiple visually presented durations were encoded and maintained. The current article explored whether this apparent modality-based difference in reference memory operation is unique to temporal stimuli or whether similar characteristics are also apparent when nontemporal stimuli are encoded and maintained. The modified temporal generalization method developed in Ogden et al. (2008) was employed; however, standards and comparisons varied by pitch (auditory) and physical line length (visual) rather than duration. Pitch and line length generalization results indicated that increasing memory load led to more variable responding and reduced recognition of the standard; however, there was no systematic shift in the location of peak responding. Comparison of the results of this study with those of Ogden et al. (2008, 2010) suggests that although performance deterioration as a consequence of increases in memory load is common to auditory temporal and nontemporal stimuli and visual nontemporal stimuli, systematic interference is unique to auditory temporal processing.

Auditory and visual temporal sensitivity: evidence for a hierarchical structure of modality-specific and modality-independent levels of temporal information processing

The present study investigated modality-specific differences in processing of temporal information in the subsecond range. For this purpose, participants performed auditory and visual versions of a rhythm perception and three different duration discrimination tasks to allow for a direct, systematic comparison across both sensory modalities. Our findings clearly indicate higher temporal sensitivity in the auditory than in the visual domain irrespective of type of timing task. To further evaluate whether there is evidence for a common modality-independent timing mechanism or for multiple modality-specific mechanisms, we used structural equation modeling to test three different theoretical models. Neither a single modality-independent timing mechanism, nor two independent modality-specific timing mechanisms fitted the empirical data. Rather, the data are well described by a hierarchical model with modality-specific visual and auditory temporal processing at a first level and a modality-independent processing system at a second level of the hierarchy.

Cognitive abilities explaining age-related changes in time perception of short and long durations

The current study investigated how the development of cognitive abilities explains the age-related changes in temporal judgment over short and long duration ranges from 0.5 to 30s. Children (5- and 9-year-olds) as well as adults were given a temporal bisection task with four different duration ranges: a duration range shorter than 1s, two duration ranges longer than 3s (4-8s and >15s), and an intermediate duration range (1.25-2.5s). Their cognitive abilities were also assessed using a series of neuropsychological tests. The results showed that temporal sensitivity improved with age for each duration range but that this improvement occurred earlier for the short durations than for the long durations. Furthermore, the results revealed that the age-related improvement in time sensitivity for the durations shorter than 1s was explained by the development of short-term memory span, whereas that for long durations was explained by the development of attention/executive functions. To summarize, the development of the abilities required to process long durations seems to be explained mainly by the development of attentional resources.

Processing Visual Temporal Information and Its Relationship to Psychometric Intelligence

According to previous studies there is a well-established functional relationship between temporal resolution power (TRP), assessed by auditory psychophysical timing tasks, and psychometric intelligence. Here we investigated whether the relationship between psychometric intelligence and temporal information processing can be also observed in the visual modality. For this purpose, performance on four visual psychophysical timing tasks (duration discrimination with filled and empty intervals, temporal generalization, and rhythm perception) was examined and related to performance on a psychometric test of intelligence. Correlational analyses indicated a reliable positive association between performance on each of the four temporal tasks and psychometric intelligence. Structural equation modeling suggested that performance on the four tasks can be assigned to one latent variable, referred to as TRP, which explained 16.5% of variance of psychometric intelligence. Findings indicate that the functional relationship previously observed between auditory temporal processing and psychometric intelligence can be generalized to the visual modality.

Dividing time: concurrent timing of auditory and visual events by young and elderly adults

This article examines age differences in individual's ability to produce the durations of learned auditory and visual target events either in isolation (focused attention) or concurrently (divided attention). Young adults produced learned target durations equally well in focused and divided attention conditions. Older adults, in contrast, showed an age-related increase in timing variability in divided attention conditions that tended to be more pronounced for visual targets than for auditory targets. Age-related impairments were associated with a decrease in working memory span; moreover, the relationship between working memory and timing performance was largest for visual targets in divided attention conditions.

The effects of age on channel capacity for absolute identification of tonal duration

We compared the ability of younger and older adults to identify which 2-kHz tones of eight varying durations was presented on a trial with their ability to discriminate between adjacent pairs of duration-varying tones drawn from the same set. We used signal detection analyses to construct scales of perceived duration for both tasks. Scales derived from pairwise comparisons of adjacent durations were related linearly to the logarithm of stimulus duration; these were essentially identical in younger and older adults. However, scales derived from the eight-alternative absolute identification experiments, which were also linearly related to the logarithm of duration, indicated that older adults outperformed younger adults on this task. These results suggest that the ability to process large numbers of stimuli that differ only in duration is at least as good, if not better, in older than in younger adults, relative to the ability of each group to discriminate between two stimuli differing only in duration.