Processing demand modulates the effects of spatial attention on the judged duration of a brief stimulus

How does attention influence the judged duration of a brief stimulus? In the four experiments reported here, we show that the effect of spatial attention on duration judgment depends on the processing demand of the concurrent nontemporal task. When participants had to perform a speeded letter discrimination task in addition to duration rating, the judged duration was longer at a cued location than at an uncued location, regardless of whether the cue was exogenous or endogenous. However, when the same stimuli were presented but no concurrent nontemporal task was required, duration was judged to be shorter at the cued location, as compared with the uncued locations. Furthermore, although spatial attention influenced duration judgment, no object-based attentional effects were found. These findings suggest that, although spatial attention plays an important role in the judged duration of a briefly presented stimulus, its effect is mediated by the processing demand of the task.     

Processing demand modulates the effects of spatial attention on the judged duration of a brief stimulus.

How does attention influence the judged duration of a brief stimulus? In the four experiments reported here, we show that the effect of spatial attention on duration judgment depends on the processing demand of the concurrent nontemporal task. When participants had to perform a speeded letter discrimination task in addition to duration rating, the judged duration was longer at a cued location than at an uncued location, regardless of whether the cue was exogenous or endogenous. However, when the same stimuli were presented but no concurrent nontemporal task was required, duration was judged to be shorter at the cued location, as compared with the uncued locations. Furthermore, although spatial attention influenced duration judgment, no object-based attentional effects were found. These findings suggest that, although spatial attention plays an important role in the judged duration of a briefly presented stimulus, its effect is mediated by the processing demand of the task.     

The Effect of Nontemporal Information Processing on Time Estimation in Pigeons

Pigeons' ability to time a stimulus while simultaneously engaged in another information-processing task was examined in three experiments using a matching-to-sample procedure. Pigeons were trained to match temporal samples of 2 and 10 s and were tested with durations of 2, 3, 4.5, 6.7, or 10 s while simultaneously processing information from another dimension. Experiment 1 revealed that the psychophysical curve for long judgments taken when pigeons also had to evaluate line orientation was shifted to the right of a control curve taken from trials on which only time had to be judged. In Experiment 2, results from probe duration tests showed that processing the spatial location of a stimulus while attending to duration caused a more general loss of timing ability across the probe durations (shorter durations were judged as longer and longer durations were judged as shorter). In Experiment 3, a distracter light was illuminated on some probe trials to determine how such a perceptual distraction would affect time judgments on the probe trials. Results showed a general loss of timing ability similar to that found in Experiment 2. It is proposed that the data might best be explained by a divided-attention effect rather than by a systematic effect on the timing mechanism.     

The influence of affective factors on time perception

Several studies have suggested that both affective valence and arousal affect the perception of time. However, in previous experiments, the two affective dimensions have not been systematically controlled. In this study, standardized photographic slides rated for emotional valence and arousal were projected to two groups of subjects for 2, 4, and 6 sec. One group of subjects estimated the projection duration on an analog scale, whereas the second group of subjects reproduced the intervals by pushing a button. Heart rate and skin conductance responses were also recorded during stimulus presentation as indices of attention and arousal. Time estimation results showed neither a main effect of valence nor a main effect of arousal. A highly significant valence × arousal interaction affected duration judgments. For low-arousal stimuli, the duration of negative slides was judged relatively shorter than the duration of positive slides. For high-arousal stimuli, the duration of negative slides was judged longer than the duration of positive slides. The same interaction pattern was observed across judgment modalities. These results are interpreted in terms of a model of action tendency, in which the level of arousal controls two different motivational mechanisms, one emotional and the other attentional.     

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.     

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 effects of interference and retention delay on temporal generalization performance

This study investigated the effect of forgetting of the standard duration on temporal discrimination in a generalization task. In two experiments, participants were given a temporal generalization task with or without a retention delay between the learning of the standard duration and the testing of the comparison durations. During this delay, they either performed or did not perform an interference task. Results failed to reveal any effect of 15-min and 24-h retention delays on time judgments (Experiment 1). However, when an interference task was performed during the 15-min delay (Experiment 2), there was a subjective shortening effect, indicating that the standard duration was judged shorter with than without an interference task. These findings suggest that when an interference task occurs immediately after initial temporal encoding, it affects the process of consolidation in reference memory.     

Auditory temporal order and perceived fusion-nonfusion

A pair of pure-tone sine waves, with the first tone presented randomly to either ear, was presented simultaneously or sequentially. The order of occurrence of the tones (temporal order) and the number of tones perceived (fusion-nonfusion) were judged. Three values of stimulus intensity (40, 55, and 70 dB SPL) and 10 values of stimulus onset asynchrony (SOA; 0, 1, 2, and 4 to 28 msec in 4-msec steps) were varied. Of major importance in this investigation was the relationship between the judgmental tasks of temporal order and fusion-nonfusion. Response time and accuracy were the dependent measures used to assess that relationship. The results of two groups of 10 subjects showed an increase in the percentage of correct nonfusion judgments with increases in stimulus intensity and SOA. For correct judgments of temporal order, no significant intensity or SOA effects were noted. Response time for the fusion-nonfusion task was significantly influenced by both stimulus intensity and SOA. For the response times associated with the temporal order task, intensity was significant. More important to this investigation was the observed Intensity by SOA by Task interaction for response time data. These results suggest a hybrid model, with different processes occurring within different stages of this model.     

Time perception and attention: The effects of prospective versus retrospective paradigms and task demands on perceived duration

This research was designed to compare time judgments obtained under prospective conditions (in which subjects are instructed to attend to time) and retrospective conditions (in which subjects are unaware that they will be required to judge time). In Experiment 1, subjects prospectively or retrospectively judged the duration of intervals spent performing a perceptual-motor task at different levels of difficulty. The results showed that subjects tested under both research paradigms tended to give increasingly shorter and/or more inaccurate time judgments with increases in nontemporal task demands. Experiment 2 was designed to test the effects of attentional deployment on perceived time by comparing prospective and retrospective judgments under control, selective attention, and divided attention conditions. Both types of time judgments became increasingly inaccurate as attention was more broadly deployed. The results of these experiments are consistent with an attentional allocation model, and they suggest that nontemporal task demands disrupt or interfere with timing in both prospective and retrospective situations.     

Attentional bias toward low-intensity stimuli: an explanation for the intensity dissociation between reaction time and temporal order judgment?

If two stimuli need different times to be processed, this difference should in principle be reflected both by response times (RT) and by judgments of their temporal order (TOJ). However, several dissociations have been reported between RT and TOJ, e.g., RT is more affected than TOJ when stimulus intensity decreases. One account for these dissociations is to assume differences in the allocation of attention induced by the two tasks. To test this hypothesis, different distributions of attention were induced in the present study between two stimulus positions (above and below fixation). Only bright stimuli appeared in one position and either bright or dim stimuli in the other. In the two RT experiments, participants had to respond to every stimulus appearing in one of the two positions. Reaction times to bright stimuli were faster when they appeared in the position where dim stimuli were likely to occur. This finding suggests that the allocation of attention was adapted to the asymmetrical arrangement of stimuli, not suggested by explicit instruction. In the two TOJ experiments, the temporal order of stimuli appearing in the two positions had to be judged. Although bright stimuli appearing at the bright-and-dim location were judged to be earlier, this effect was small and insignificant. Further, the intensity dissociation between RT and TOJ was insensitive to random vs blockwise presentations of intensities, therefore was not modified by attentional preferences. Thus, asymmetrical arrangement of stimuli has an impact on the allocation of attention, but only in the RT task. Therefore dissociations between TOJ and response times cannot be accounted for by an attentional bias in the TOJ task but probably by different use of temporal information in the two tasks.     

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.     

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.     

Time judgments of musical endings: effects of expectancies on the "filled interval effect"

In two experiments, the influence of musical endings on duration judgments was examined. In Experiment 1, subjects were asked to compare the duration of paired folk tunes that could vary in their degree of resolution. Results showed that melodies ending on the leading tone interval were underestimated relative to songs ending on the conventional tonic. Experiment 2 further revealed that time estimates were influenced by a melody's preceding temporal accent structure. Melodies ending earlier than expected were judged significantly shorter, particularly when the tune ended on the leading-tone interval. Conversely, tonic endings were judged substantially longer when they appeared to occur "too late" in time. Results are discussed in terms of a contrast model which emphasizes the role of expectancies on duration judgments.     

Effects of amount of attention allocated to the location of visual stimulus pairs on perception of simultaneity

This study examined whether a change in the amount of attention equally allocated to two locations affects judgments of the simultaneity or successiveness of stimuli presented at those locations. Observers were cued to expect two brief flashes either to the left and right of fixation or above and below fixation. Stimulus onset asynchrony was randomly varied. On a small proportion of trials, the stimuli appeared at the unexpected locations. Observers were more likely to report the stimuli as simultaneous when they appeared in the unexpected locations. A model proposed to account for the data assumes that a brief stimulus event is represented by a probability distribution reflecting the uncertainty in determining the time of the event’s occurrence, and two events are judged to be simultaneous if they are perceived to fall within some critical temporal interval, c, which is a function of the amount of attention allocated to the task.     

Time flies with music whatever its emotional valence

The present study used a temporal bisection task to investigate whether music affects time estimation differently from a matched auditory neutral stimulus, and whether the emotional valence of the musical stimuli (i.e., sad vs. happy music) modulates this effect. The results showed that, compared to sine wave control music, music presented in a major (happy) or a minor (sad) key shifted the bisection function toward the right, thus increasing the bisection point value (point of subjective equality). This indicates that the duration of a melody is judged shorter than that of a non-melodic control stimulus, thus confirming that “time flies” when we listen to music. Nevertheless, sensitivity to time was similar for all the auditory stimuli. Furthermore, the temporal bisection functions did not differ as a function of musical mode.     

Subjective time: Cognitive and physical secondary tasks affect timing differently

Humans were trained on a temporal discrimination to make one response when the stimulus duration was short (2 s) and a different response when the stimulus duration was long (8 s). They were then tested with stimulus durations in between to determine the bisection point. In Experiment 1, we examined the effect of a secondary cognitive task (counting backwards by threes) on the bisection point when participants were trained without a cognitive load and were tested with a cognitive load or the reverse (relative to appropriate controls). When the cognitive load increased from training, the psychophysical function plotting long responses against the increase in stimulus duration shifted to the right (as if the internal clock slowed down), and when the cognitive load decreased from training the psychophysical function shifted to the left (as if the internal clock speeded up). In Experiment 2, when the secondary task consisted of exerting continuous force on a transducer (a physically effortful task), it had the opposite effect. When the required force increased from training, the psychophysical function shifted to the left (as if the internal clock speeded up), and when the required force decreased from training, the psychophysical function shifted to the right (as if the internal clock slowed down). The results support an attentional view of the subjective passage of time. A cognitive secondary task appears to decrease attention to temporal cues, resulting in the underestimation of the passage of time, whereas a force requirement appears to increase attention to temporal cues, resulting in the overestimation of the passage of time.     

Combining experiences over time: the effects of duration,intensity changes and on-line measurements on retrospective pain evaluations

Two experiments were conducted to examine the effects of various factors on retrospective pain evaluation. The factors examined in Experiment 1 were the rate and pattern of change, the intensity (particularly the final intensity), and the duration of the painful experience. Experiment 2 manipulated these factors and, in addition, examined the effect of continuous (on-line) ratings on the overall retrospective evaluation. The two experiments utilized different pain modalities, heat in the first and mechanical pressure in the second. In addition, all subjects in Experiment 1 experienced stimuli with the same physical magnitude, while in Experiment 2 stimuli were individually tailored to make them subjectively equivalent. In both experiments, subjects were presented with a series of painful stimuli and evaluated the intensity of each stimulus immediately upon its termination. The stimuli themselves were composed of multiple intensity levels that differentially changed over time (Intensity-Patterns). Subjects' on-line ratings in Experiment 2 closely mirrored the physical patterns of the intensities. The main conclusion from both experiments is that the retrospective evaluations of painful experiences are influenced primarily by a combination of the final pain intensity and the intensity trend during the latter half of the experience. In addition, results indicated that duration has little impact on retrospective evaluations for stimuli of relatively constant intensity. However, when the stimulus intensity changes over time, duration does play a role. Finally, the task of continuously reporting the stimulus intensity had a moderating impact on the retrospective evaluations. © 1998 John Wiley & Sons, Ltd.     

Subjective time: cognitive and physical secondary tasks affect timing differently

Humans were trained on a temporal discrimination to make one response when the stimulus duration was short (2 s) and a different response when the stimulus duration was long (8 s). They were then tested with stimulus durations in between to determine the bisection point. In Experiment 1, we examined the effect of a secondary cognitive task (counting backwards by threes) on the bisection point when participants were trained without a cognitive load and were tested with a cognitive load or the reverse (relative to appropriate controls). When the cognitive load increased from training, the psychophysical function plotting long responses against the increase in stimulus duration shifted to the right (as if the internal clock slowed down), and when the cognitive load decreased from training the psychophysical function shifted to the left (as if the internal clock speeded up). In Experiment 2, when the secondary task consisted of exerting continuous force on a transducer (a physically effortful task), it had the opposite effect. When the required force increased from training, the psychophysical function shifted to the left (as if the internal clock speeded up), and when the required force decreased from training, the psychophysical function shifted to the right (as if the internal clock slowed down). The results support an attentional view of the subjective passage of time. A cognitive secondary task appears to decrease attention to temporal cues, resulting in the underestimation of the passage of time, whereas a force requirement appears to increase attention to temporal cues, resulting in the overestimation of the passage of time.     

工作记忆的存储时间及目标时距对时间知觉的影响

本研究操作记忆信息与计时开始之间的时间间隔（ISI）和目标时距,探讨工作记忆影响时间判断的灵活性。被试首先记忆一个客体,然后在每个trial的最后判断测试刺激是否与记忆项相同;在延迟阶段,被试完成时间判断任务,即判断相继出现的两个刺激的时距哪个更长（或更短）。时间任务中的一个刺激与记忆内容完全相同,相应的另一个刺激与记忆内容在形状和颜色上都不同。重复条件下,被试忽略第一个刺激,仅完成时间判断任务。结果发现,时间间隔（ISI）短时,记忆匹配条件下的准确率更高,匹配刺激延长了知觉的时间;但随着时间间隔的增加,工作记忆匹配对时间判断的影响降低甚至消失。并且,长或短ISI,记忆任务或重复条件下,目标时距长时,记忆匹配反而缩短了知觉的时间。研究说明工作记忆对时间判断的影响是灵活的,受到注意或工作记忆等高级认知系统的调控。     

Time judgments of musical endings: Effects of expectancies on the “filled interval effect”

In two experiments, the influence of musical endings on duration judgments was examined. In Experiment 1, subjects were asked to compare the duration of paired folk tunes that could vary in their degree of resolution. Results showed that melodies ending on the leading tone interval were underestimated relative to songs ending on the conventional tonic. Experiment 2 further revealed that time estimates were influenced by a melody’s preceding temporal accent structure. Melodies ending earlier than expected were judged significantly shorter, particularly when the tune ended on the leading-tone interval. Conversely, tonic endings were judged substantially longer when they appeared to occur “too late” in time. Results are discussed in terms of a contrast model which emphasizes the role of expectancies on duration judgments