Involvement of shared resources in time judgment and sequence reasoning tasks

Previous research suggests that time perception is supported by the same attentional resources involved in sequence processing. The present experiment was designed to clarify this connection by examining the relation between timing and reasoning tasks that involved either sequencing or non-sequencing judgments. For the timing task, subjects produced a series of 5-s intervals. For the reasoning tasks, subjects judged whether pairs of statements describing common actions either (a) were presented in the correct temporal order (sequencing), or (b) described similar actions or objects (similarity). Subjects performed the timing and reasoning tasks both separately and concurrently in a series of 3-minute trials. Comparisons of single-task and dual-task performance assessed interference patterns between concurrent tasks. Both reasoning tasks interfered with timing by making temporal productions longer and more variable. Timing had differential effects on the two reasoning tasks. Concurrent timing caused sequencing judgments to become slower, less accurate, and less sensitive relative to sequencing-only conditions. In contrast, similarity judgments were either unaffected or affected to a lesser degree by the concurrent timing task. These results support the notion that timing and sequencing are closely related processes that rely on the same set of cognitive resources or mechanisms.     

Attentional resources in timing: Interference effects in concurrent temporal and nontemporal working memory tasks

Three experiments examined interference effects in concurrent temporal and nontemporal tasks. The timing task in each experiment required subjects to generate a series of 2- or 5-sec temporal productions. The nontemporal tasks were pursuit rotor tracking (Experiment 1), visual search (Experiment 2), and mental arithmetic (Experiment 3). Each nontemporal task had two levels of difficulty. All tasks were performed under both single- and dual-task conditions. A simple attentional allocation model predicts bidirectional interference between concurrent tasks. The main results showed the classic interference effect in timing. That is, the concurrent nontemporal tasks caused temporal productions to become longer (longer productions represent a shortening of perceived time) and/or more variable than did timing-only conditions. In general, the difficult version of each nontemporal task disrupted timing more than the easier version. The timing data also exhibited a serial lengthening effect, in which temporal productions became longer across trials. Nontemporal task performance showed a mixed pattern. Tracking and visual search were essentially unaffected by the addition of a timing task, whereas mental arithmetic was disrupted by concurrent timing. These results call for a modification of the attentional allocation model to incorporate the idea of specialized processing resources. Two major theoretical frameworks—multiple resource theory and the working memory model—are critically evaluated with respect to the resource demands of timing and temporal/ nontemporal dual-task performance.     

Attention and interference in prospective and retrospective timing.

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

The role of practice and automaticity in temporal and nontemporal dual-task performance

Research on time and attention shows that a nontemporal task may interfere with a concurrent timing task by making time judgments shorter, more variable, and/or more inaccurate compared to timing-only conditions. Brown (1998, Psychological Research, 61, 71-81) counteracted the interference effect by giving subjects automaticity training on a nontemporal task to reduce the amount of processing resources the task required. Such practice attenuated interference in timing. Two new experiments were designed to replicate and extend the previous findings. Subjects generated a series of 5-s temporal productions under single-task (timing only) and dual-task (timing plus nontemporal task) conditions. The nontemporal tasks were pursuit rotor tracking (Experiment 1), and mirror-reversed reading (Experiment 2). We employed a pretest-practice-posttest paradigm, with the practice sessions devoted to performance of the nontemporal task. Pretest-posttest comparisons showed that practice reduced interference in timing in both experiments. Dual-task probe trials were given during the practice sessions to trace the time course of the improvement in timing. The results showed that interference in timing was reduced with even small amounts of practice. The findings support the idea that timing is very sensitive to changes in the allocation of attentional resources.     

Automaticity versus timesharing in timing and tracking dual-task performance

Two experiments investigated the interfering effects of a manual tracking task on timing performance. Subjects generated a series of 5-s temporal productions under control (timing only) and experimental (timing + pursuit rotor tracking) conditions. Timing was more variable under experimental conditions, a finding consistent with attentional models which argue that timing tasks compete with concurrent distractor tasks for limited processing resources. A pretest-posttest paradigm was employed to evaluate the hypothesis that practice on the tracking task would lessen its attentional demands and thereby attenuate the interference effect. Experiment 1 involved single-task practice (tracking alone). Single-task practice leads to automaticity, the ability to perform a skilled task using fewer processing resources. Pretest-posttest comparisons showed that such practice reduced interference in timing. Experiment 2 involved dual-task practice (timing + tracking). Dual-task practice promotes the development of timesharing, the ability to efficiently switch attention between multiple tasks. In this case, practice failed to reduce the interference effect in timing. The results suggest that effective strategies for timing in dual-task situations must allow one to closely monitor the ongoing flow of temporal events. Received: 11 November 1996 / Accepted: 6 May 1997     

Processing resources in timing and sequencing tasks

Subjects performed timing and sequencing tasks under separate (single-task) and concurrent (dual-task) conditions in two experiments. The timing task required the subjects to generate a series of 5-sec temporal productions. The sequencing task in Experiment 1 involved verifying reasoning statements that described the ordering of a pair of letters. The task in Experiment 2 involved monitoring a familiar event sequence and detecting omissions in that sequence. Comparisons of single-task and dual-task conditions showed a pattern of bidirectional interference. In each experiment, the concurrent sequencing task caused temporal productions to become more variable and longer. The concurrent timing task interfered with sequencing by lengthening response times to the reasoning statements (Experiment 1) and by lengthening response times to sequence omissions and reducing sensitivity at detecting the omissions (Experiment 2). The results suggest that time perception and sequence perception are related cognitive processes that rely on a common set of attentional resources.     

Timing and executive function: Bidirectional interference between concurrent temporal production and randomization tasks

A review of interference effects in concurrent temporal/nontemporal dual-task studies suggests that prospective timing may be related to executive cognitive functions. Executive processes play a supervisory role in behavior by controlling attention, coordinating information, and scheduling actions. In the present research, a timing task was paired with an established executive task in a dual-task paradigm. The timing task required subjects t o generate a series o f 5-sec temporal productions,and the executive task was random number generation. These tasks were performed both separately and concurrently. Comparisons of single-task and dual-task conditions showed that (1) the randomization task interfered with timing by making temporal productions more variable and longer and (2) concurrent timing disrupted randomization performance by making responses less random. This pattern of bidirectional interference supports the idea that timing relies on the same attentional resources used by other executive-level tasks.     

Time perception,attention, and memory: A selective review

This article provides a selective review of time perception research, mainly focusing on the authors' research. Aspects of psychological time include simultaneity, successiveness, temporal order, and duration judgments. In contrast to findings at interstimulus intervals or durations less than 3.0–5.0 s, there is little evidence for an “across-senses” effect of perceptual modality (visual vs. auditory) at longer intervals or durations. In addition, the flow of time (events) is a pervasive perceptual illusion, and we review evidence on that. Some temporal information is encoded All rights reserved. relatively automatically into memory: People can judge time-related attributes such as recency, frequency, temporal order, and duration of events. Duration judgments in prospective and retrospective paradigms reveal differences between them, as well as variables that moderate the processes involved. An attentional-gate model is needed to account for prospective judgments, and a contextual-change model is needed to account for retrospective judgments.     

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 30 s. 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 1 s, two duration ranges longer than 3 s (4-8 s and >15 s), and an intermediate duration range (1.25-2.5 s). 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 1 s 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.     

Attention allocation policy influences prospective timing

The role of attention allocation policy control in prospective duration judgments was tested in two experiments. In the first experiment, it was demonstrated that prospective duration judgments of same clock durations are longer when timing is treated as a primary task than when it is treated as a secondary task, regardless of the difficulty of the nontemporal task filling the to-be-judged interval. In the second experiment, this finding was replicated. Additionally, it was demonstrated that when prospective timing is not preassigned a specific priority, duration judgments are longer than those obtained under secondary-task conditions, but shorter than those obtained under primary-task conditions. It was also revealed that when attention is distracted from timing, prospective duration judgments become shorter than when attention is not distracted. These findings support the notion that prospective timing creates a dual-task condition in which magnitude of duration judgments reflects the amount of attentional resources allocated for temporal information processing.     

The effects of divided attention on encoding processes in memory: mapping the locus of interference.

Despite the detrimental effects of divided attention at encoding on later memory performance, results described in the literature do not unequivocally specify which processes are interrupted during encoding by participants' occupation with a concurrent task. Using a processing analysis framework where the encoding process is viewed as a multiphase mental activity, the current research investigated this issue using a new differential temporal interference paradigm where the study phase of single words was interrupted at different temporal segments. In two experiments, we used performance on both memory and online choice reaction time tasks to assess whether such differential interference would produce different degrees of reduction in participants' later memory performance, as well as changes in the attentional resources required to execute each of the encoding phases. Measures of memory and concurrent task performance in the two experiments converged on similar patterns, showing that all phases of encoding are affected by the concurrent task. However, the initial encoding phase, which is tentatively associated with the initial registration of information, seems especially vulnerable to interference.     

Effects of internal clock and memory disorders on duration reproductions and duration productions in patients with Parkinson's disease

Patients with Parkinson's disease (PD) exhibit deficits in perceptual and motor timing as well as impairments in memory and attentional processes that are related to dysfunction of dopaminergic systems in the basal ganglia. The aim of the present study was to assess the relationships existing between impaired duration judgments and defective memory and attention in PD patients. We compared time performance of medicated PD patients and control subjects on a duration reproduction task that is highly memory-dependent, and on a duration production task that could reveal effects of changes in the speed of internal time-keeping mechanisms. Each task was performed in a control counting condition and in a condition requiring divided attention between the temporal task and a concurrent reading task. Moreover, PD patients and control subjects were assessed on memory and attention using a battery of neuropsychological tests. The results revealed that in the concurrent reading condition of the reproduction task, duration judgments tended to be more variable in PD patients than in control subjects. Moreover, variability of duration reproductions was correlated with both measures of memory and of disease severity. In the concurrent reading condition of the production task, duration judgments were significantly shorter in PD patients than in control subjects, and accuracy of duration productions was correlated with scores on sub-tests of short-term memory. The findings suggest that the administration of dopamine did not entirely remove the memory deficits in PD patients. Moreover, DA treatment would have abnormally accelerated the rate of the internal clock leading to shorter duration productions in PD patients. The whole results indicate that dopamine administration in patients might have overshadowed the slowing rate of the internal clock usually reported in non medicated PD patients, without entirely restoring all of the memory functions.     

Attentional capacity is undifferentiated: concurrent discrimination of form, color, and motion

We report a series of experiments on the concurrent discrimination of form, color, and motion attributes. All tasks involved joint discrimination of attributes, and positions and were highly demanding of attention. We quantified interference between concurrent discriminations by establishing the attention-operating characteristic. Interference was indistinguishable for similar and dissimilar task combinations (form-form, color-color, motion-motion, and color-form, color-motion, motion-color, and motion-form, respectively). These results suggest strongly that different visual discriminations draw on the same attentional capacity--in other words, that the capacity of visual attention is undifferentiated.     

Judgments of temporal duration while processing verbal and physiognomic stimuli

Left- and right-handed male college students made verbal estimations of temporal durations during performance of recognition memory for words and faces, and with no concurrent task. Time judgments were shorter with both concurrent memory tasks than in the control condition, but did not differ between the two memory tasks. Also, these results were additive across groups. Considering the differential involvement of the two cerebral hemispheres in processing verbal and physiognomic stimuli, and the lack of an interaction between group (left- vs right- handers) and memory task, it was concluded that the results do not support a lateralization of function hypothesis with respect to judgments of temporal duration.     

The attenuation effect in timing: counteracting dual-task interference with time-judgment skill training

A basic finding in the time-perception literature is an interference effect in dual-task conditions involving concurrent timing and distractor tasks. Dual-task conditions typically cause time judgments to become less accurate than single-task conditions in which subjects judge time alone. Previous research (Brown, 1998 Psychological Research 61 71-81; Brown and Bennett, 2002 Psychological Research 66 80-89) has shown that practice on the distractor task reduces interference, a phenomenon called the attenuation effect. The present research was designed to determine whether practice on the time-judgment task would produce a similar result. In experiment 1, subjects reproduced 6-14 s intervals in a series of practice trials. Some subjects received feedback regarding the accuracy of each response and others received no feedback. Subsequent testing under dual-task (timing + digit memory) conditions showed that feedback training reduced interference. In experiment 2, the practice trials included both single-task and dual-task conditions. Later tests showed that feedback training eliminated the interference effect. The results highlight the role of attentional resources, the transfer of skills, and compensatory decision processes in time-judgment skill training.     

Temporal production and visuospatial processing

Current models of prospective timing hypothesize that estimated duration is influenced either by the attentional load or by the short-term memory requirements of a concurrent nontemporal task. In the present study, we addressed this issue with four dual-task experiments. In Exp. 1, the effect of memory load on both reaction time and temporal production was proportional to the number of items of a visuospatial pattern to hold in memory. In Exps. 2, 3, and 4, a temporal production task was combined with two visual search tasks involving either pre-attentive or attentional processing. Visual tasks interfered with temporal production: produced intervals were lengthened proportionally to the display size. In contrast, reaction times increased with display size only when a serial, effortful search was required. It appears that memory and perceptual set size, rather than nonspecific attentional or short-term memory load, can influence prospective timing.     

The effect of a prior presentation on temporal judgments in a perceptual identification task

Subjects read aloud words presented once at the rate of one per second. A perceptual identification task, involving 30- or 50-msec presentations, followed. Some of the words presented for identification had been read previously; others were new. After each presentation, in addition to identifying the word, the subjects judged its duration. The data indicate that a single presentation of a word affects its later perception, as revealed by enhanced perceptual identification, longer duration judgments, and better temporal discrimination. A second experiment showed that a single presentation influenced duration judgments even when identification was not required. The final experiment addressed the issue of what is preserved in memory from a prior presentation. The results from the three experiments indicate that duration judgments provide a valuable dependent measure of memory in the perceptual identification task and support the misattribution hypothesis: A prior presentation enhances perceptual identification, and this increase in relative perceptual fluency is incorrectly attributed to a longer presentation duration.     

Prospective duration judgments: The role of temporality and executive demands of concurrent tasks

It is known that concurrent non-temporal tasks shorten reproduced temporal durations in prospective duration judgments. Two experiments were carried out, one comparing a concurrent temporal task to a minimally demanding concurrent task (Experiment 1) and one comparing an executive concurrent (Simon) task with a less demanding non-executive concurrent task (Experiment 2). An effect of the concurrent task type on temporal reproductions was found. Furthermore, a duration length effect was found, where longer durations were underestimated more than shorter durations. This effect tended to be stronger for the experiments that included a concurrent task that demanded high attention.     

Temporal processing capabilities in repetition conduction aphasia

This study investigates the temporal resolution capacities of the central-auditory system in a subject (NP) suffering from repetition conduction aphasia. More specifically, the patient was asked to detect brief gaps between two stretches of broadband noise (gap detection task) and to evaluate the duration of two biphasic (WN-3) continuous noise elements, starting with white noise (WN) followed by 3 kHz bandpass-filtered noise (duration discrimination task). During the gap detection task, the two portions of each stimulus were either identical (“intra-channel condition”) or differed (“inter-channel condition”) in the spectral characteristics of the leading and trailing acoustic segments. NP did not exhibit any deficits in the intra-channel condition of the gap detection task, indicating intact auditory temporal resolution across intervals of 1–3 ms. By contrast, the inter-channel condition yielded increased threshold values. Based upon the “multiple-looks” model of central-auditory processing, this profile points at a defective integration window operating across a few tens of milliseconds – a temporal range associated with critical features of the acoustic speech signal such as voice onset time and formant transitions. Additionally, NP was found impaired during a duration discrimination task addressing longer integration windows (ca. 150 ms). Concerning speech, this latter time domain approximately corresponds to the duration of stationary segmental units such as fricatives and long vowels. On the basis of our results we suggest, that the patient’s auditory timing deficits in non-speech tasks may account, at least partially, for his impairments in speech processing.     

Timing in a dual-task in children and adults: when the interference effect is higher with concurrent non-temporal than temporal information

This study used a dual task with participants of different levels of cognitive capacities, assessed with neuropsychological tests, to examine the attentional cost on time judgment of processing concurrent temporal and non-temporal information. Children and adults performed a temporal reproduction task with either an interfering temporal or non-temporal discrimination task. The results showed an underestimation of time in the dual task compared to the single task, the extent of which was directly linked to individual attentional capacities. However, the non-temporal task interfered more than the temporal task on the reproduced durations. Nonetheless, the temporal reproduction task equally affected performance in the non-temporal and the temporal discrimination task. These results reveal the predominant role of the cost of dual-tasking in interference effects on time judgment, and the lesser role of concurrent information, especially of temporal information. This suggests a lack of competition for attentional resources in the processing of multiple durations.