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.     

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.     

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 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.     

Controlled attention sharing influences time estimation

A seminal attentional model of time estimation predicts that subjective duration will be positively correlated to the amount of attention given to temporal processing. This prediction holds under prospective conditions, in which one is forewarned that judgments of time will be asked, in contrast to retrospective conditions, in which such judgments are required after the relevant period without any prior warning. In three experiments, an attention-sharing method was used. Subjects were asked to control the amount of attention that they devoted to one or the other component of a dual-task paradigm. The first experiment involved word categorization and reproduction of duration. The following experiments, based on signal detection theory, required discrimination of both the duration and the intensity of a single stimulus, in the visual (Experiment 2) or the auditory (Experiment 3) modality. The results indicate that when the attention is directly controlled by the subject, the subjective duration shortens as the amount of attention devoted to the temporal task diminishes. The implications of these results for the possible existence of an internal timer are considered.     

Children's working memory: investigating performance limitations in complex span tasks

Three experiments investigated the roles of resource-sharing and intrinsic memory demands in complex working memory span performance in 7- and 9-year-olds. In Experiment 1, the processing complexity of arithmetic operations was varied under conditions in which processing times were equivalent. Memory span did not differ as a function of processing complexity. In Experiment 2, complex memory span was assessed under three conditions designed to vary both processing and intrinsic storage demands: mental arithmetic (significant attentional demands-requires storage), odd/even judgments (significant attentional demands-no storage required), and articulatory suppression (minimal attentional demands--no storage required). The highest memory spans were found in the articulatory suppression task. Span was at an intermediate level with arithmetic processing and was lowest for processing involving odd/even judgments. This difference in memory span for processing tasks involving arithmetic processing and odd/even judgments was eliminated in Experiment 3 when the pacing requirements of the arithmetic and odd/even processing tasks were equated. The results are consistent with the view that complex memory span performance is disrupted by processing activities that divert attentional resources from storage.     

Remembered duration: working memory and the reproduction of intervals

On the basis of attention allocation models of time estimation, the role of working memory in prospective duration reproduction is explored. In four experiments, adult participants performed a counting task (duration, 400 sec) that allowed coordinative and sequential demands on working memory to be varied. After completing the counting task, the participants reproduced the time that they had worked on this task It emerged that (1) increased coordinative demands on working memory (but not increased sequential demands) reduced the accuracy of prospective duration reproduction (Experiments 1 and 2), (2) presenting context information during the reproduction phase enhanced the accuracy of the reproduced duration (Experiment 3), and (3) individual differences in coordinative working memory capacity affected duration reproduction in the same direction as the experimental manipulation of coordinative task demands (Experiment 4). The results suggest that attention allocation models of time estimation may benefit from taking a more differentiated view of the types of attentional demands that affect temporal cognition.     

Influence of individual differences in temporal sensitivity on timing performance

This research was designed to examine the consistency of individual differences in timing. Subjects were tested initially on a temporal-signal-detection task. In a series of trials, subjects judged whether a stimulus figure was displayed for either 12 s or greater than 12 s. Task performance was used to classify the subjects into groups with high or low temporal sensitivity (d'). Later, the subjects were tested on two classic time-judgment tasks. In a temporal-interference task, subjects reproduced intervals of 8-16 s during which they had rehearsed 0, 3, or 7 digits. Absolute error in time judgments increased linearly as a function of task demands. However, subjects with low temporal sensitivity made more error under all conditions compared with those with high sensitivity. In an isochronous-tapping task, subjects produced a series of 2-s and 5-s intervals. The low-temporal-sensitivity group produced more variable and inaccurate responses than the high-sensitivity group. The results demonstrate cross-situational consistency in timing performance across different tasks, time-judgment methods, and stimulus durations.     

The psychophysics of retrospective and prospective timing

In two experiments, different groups of subjects heard four musical selections and then estimated the duration of each selection. Some groups made retrospective time estimates while others made prospective estimates. In both experiments, analyses of the psychophysical relation between perceived and actual duration showed that the slopes of straight-line fits were flatter and accounted for a smaller proportion of the variance under retrospective as compared with prospective conditions. In addition, in experiment 1, retrospective subjects were less accurate in rank ordering the selections from longest to shortest. There was also a serial-order effect, with selections estimated longer when they occurred early in the sequence. In experiment 2 the slopes decreased as the selections in a series became longer. Both retrospective and prospective estimates also exhibited a context effect, in that estimates of a given selection were influenced by the relative durations of the other three selections in the series. The results on inaccurate retrospective judgments raise questions about prior research on stimulus factors and retrospective timing. However, similarities under retrospective and prospective conditions suggest that timing under these conditions, although different in some respects, reflects a similar process.     

Time estimation and concurrent nontemporal processing: Specific interference from short-term-memory demands

Previous studies have shown that the effect of concurrent nontempcraLprocessmg on time astimation may vary depending on the level of difficulty of the nontemporal task. This is commonly interpreted within the context of so-called distraction/interruption models of temporal processing, which propose that as concurrent task difficulty or complexity is increased, temporal processing receives less attention. We hypothesize that the effect of nontemporal processing does not depend on the level of difficulty as such, but rather on the extent to which the concurrent nontemporal task specifically involves processing in short-term meraery. Four experiments were run in which the short-term memory requirements of concurrent tasks were systematically varied, although all of the tasks were of comparable levels of difficulty. In the first experiment, the effect of memory search on simultaneous temporal productions was proportional to the number of items to search. As with reaction time, produced intervals were shown to increase linearly with the number of items in the memorized set. In Experiment 2, a visual search involving some load on short-term memory interfered in the same way with time production, although to a lesser extent. The last two experiments showed that performing attention-demanding visual search tasks that did not involve short-term memory did not lengthen simultaneously produced time inter-vals. This suggests that interference of nontemporal processing on time processing may not be a matter of nonspecific general purpose attentional resources, but rather of concurrent short-term-memory processing demands.     

Time perception with and without a concurrent nontemporal task

Prospective time estimates were obtained from human subjects for stimulus durations ranging from 2 to 23 sec. Presence and absence of a concurrent nontemporal task was manipulated within subjects in three experiments. In addition, location of the task within temporal reproduction trials and psychophysical method were varied between groups in Experiments 2 and 3, respectively. For long-duration stimuli, the results of all three experiments conformed to results in the literature, showing a decrease in perceived duration under concurrent task conditions, in accord with attentional resource allocation models of timing. The effects of task location and psychophysical method on time estimates were also compatible with this analysis. However, psychophysical functions obtained under task conditions were fit well by power functions, an outcome that would not be anticipated on the basis of attention theory. The slopes of the functions under no-task conditions were steeper than those under task conditions. The data support the perceptual hypothesis that different sources of sensory input mediate timing under task and no-task conditions.     

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.     

The relationship between the number of presented stimuli and prospective duration estimates: The effect of concurrent task activity

The attention/distraction models of prospective time estimation predict either a negative relationship or an independence between duration estimates and the number of stimulus events presented during the time period, but not a positive relationship. Two experiments examined this relationship under prospective conditions. Lists of words were presented during a 60-sec time period at either a fast or a slow rate. Subjects either passively viewed the words or actively responded by performing either a graphemic or a semantic classification task on each word. To measure subjective duration, the method of magnitude estimation was used in Experiment 1 and the method of reproduction was used in Experiment 2. Time estimates were independent of the number of presented words in the passive viewing condition, and negatively related in the classification task conditions. Furthermore, the two classification tasks had similar effects on time estimates. These findings are consistent with the attentional models of prospective timing, and they question the robustness of earlier findings of a positive relationship between time estimates of moderately long intervals and the number of presented stimuli under conditions of minimal processing of the interval events.     

The role of metacognition in prospective memory: Anticipated task demands influence attention allocation strategies

The present study investigates how individuals distribute their attentional resources between a prospective memory task and an ongoing task. Therefore, metacognitive expectations about the attentional demands of the prospective-memory task were manipulated while the factual demands were held constant. In Experiments 1a and 1b, we found attentional costs from a prospective-memory task with low factual demands to be significantly reduced when information about the low to-be-expected demands were provided, while prospective-memory performance remained largely unaffected. In Experiment 2, attentional monitoring in a more demanding prospective-memory task also varied with information about the to-be-expected demands (high vs. low) and again there were no equivalent changes in prospective-memory performance. These findings suggest that attention–allocation strategies of prospective memory rely on metacognitive expectations about prospective-memory task demands. Furthermore, the results suggest that attentional monitoring is only functional for prospective memory to the extent to which anticipated task demands reflect objective task demands.     

Children's time production for concurrent nontemporal motor tasks

An internal clock model has often been used to explain disruptions in timing production that occur when temporal and nontemporal tasks are performed simultaneously. In this study, participants' ability to walk 8 m in 8 sec. while executing various secondary concurrent nontemporal tasks was assessed for 16 children enrolled in sports at school. Children participated in six trials under five randomized task conditions involving different coordinative and cognitive workloads. The duration of timing production increased as the attention requirements or cognitive demands placed upon the completion of the task increased. However, participants also showed learning of timing over the six trials. Significant differences were found between the timing task and the concurrent nontemporal tasks depending on the difficulty and cognitive load of the secondary tasks. Results are discussed using attention models of time estimation and production.     

How cognitive load affects duration judgments: A meta-analytic review

A meta-analysis of 117 experiments evaluated the effects of cognitive load on duration judgments. Cognitive load refers to information-processing (attentional or working-memory) demands. Six types of cognitive load were analyzed to resolve ongoing controversies and to test current duration judgment theories. Duration judgments depend on whether or not participants are informed in advance that they are needed: prospective paradigm (informed) versus retrospective paradigm (not informed). With higher cognitive load, the prospective duration judgment ratio (subjective duration to objective duration) decreases but the retrospective ratio increases. Thus, the duration judgment ratio differs depending on the paradigm and the specific type of cognitive load. As assessed by the coefficient of variation, relative variability of prospective, but not retrospective, judgments increases with cognitive load. The prospective findings support models emphasizing attentional resources, especially executive control. The retrospective findings support models emphasizing memory changes. Alternative theories do not fit with the meta-analytic findings and are rejected.     

Recognition memory for distractor faces depends on attentional load at exposure

Incidental recognition memory for faces previously exposed as task-irrelevant distractors was assessed as a function of the attentional load of an unrelated task performed on superimposed letter strings at exposure. In Experiment 1, subjects were told to ignore the faces and either to judge the color of the letters (low load) or to search for an angular target letter among other angular letters (high load). A surprise recognition memory test revealed that despite the irrelevance of all faces at exposure, those exposed under low-load conditions were later recognized, but those exposed under high-load conditions were not. Experiment 2 found a similar pattern when both the high- and low-load tasks required shape judgments for the letters but made differing attentional demands. Finally, Experiment 3 showed that high load in a nonface task can significantly reduce even immediate recognition of a fixated face from the preceding trial. These results demonstrate that load in a nonface domain (e.g., letter shape) can reduce face recognition, in accord with Lavie’s load theory. In addition to their theoretical impact, these results may have practical implications for eyewitness testimony.     

Effects of attention manipulation on judgments of duration and of intensity in the visual modality

The “attentional model” of time estimation assumes that temporal judgments depend on the amount of attention allocated to the temporal processor (the timer). One of the main predictions of this model is that an interval will be judged shorter when attention is not allocated to the temporal parameters of the task. Previous studies combining temporal and nontemporal tasks (dual-task method) have suggested that the time spent processing the target duration might be a key factor: The less time devoted by the subject to the temporal task, the shorter the judged duration. In the two experiments presented here, subjects were asked to judge both the duration of a visual stimulus and an increment in intensity occurring at any time during this stimulus. In the second experiment, trials without intensity increments were added. The main result is that the judged duration was shorter when the increment occurred later in the stimulus or did not occur. In those cases, subjects had been expecting increment occurrence during most part of the stimulus and thus had focused for a shorter time on stimulus duration. We propose that attention shifts related to expectancy and to detection of the increment reduce subjective duration.     

疼痛条件下时间目标对时距估计的影响

本研究采用冷压任务引发疼痛,以健康大学生为被试,试图探讨在疼痛条件下时间目标对时距估计的影响。结果发现：疼痛条件下的时距估计值小于非疼痛条件下时距估计值,疼痛条件下具体时间目标的时距估计值显著大于无目标时距估计值。临床上给患者提供具体的时间目标或许有助于他们应对疼痛。     

Sex Bias at Work: The Effects of Attentional and Memory Demands on Performance Ratings of Men and Women1

The present study examined the impact of attentional and memory demands on work performance ratings accorded men and women in traditionally male jobs. Of interest was whether sex discrimination would abate in the face of individuating and job-relevant work behavior even when the demands likely to be faced in actual work settings were taken into account. Two hundred and two subjects read a vignette depicting the work behavior of a male or female police officer and then rated the individual's work performance. The attentional demands imposed on subjects while reading the vignette and the amount of time elapsed prior to issuing the performance ratings were systematically varied. As predicted, men were evaluated more favorably than women when raters were faced with an additional task requiring attention and time pressures were made salient. Only when subjects were able to carefully allocate all of their attentional resources did sex bias in work performance ratings abate. Memory demands had no effects on work performance ratings. Gender-related work characterizations paralleled the performance ratings, providing support for the idea that sex stereotypes mediate discrimination in performance appraisal judgments. The theoretical and practical implications of these findings, as well as suggestions for future research, are discussed.