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 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.     

Attention and memory protection: Interactions between retrospective attention cueing and interference

Visual working memory (VWM) and attention have a number of features in common, but despite extensive research it is still unclear how the two interact. Can focused attention improve VWM precision? Can it protect VWM from interference? Here we used a partial-report, continuous-response orientation memory task to examine how attention and interference affect different aspects of VWM and how they interact with one another. Both attention and interference were orthogonally manipulated during the retention interval. Attention was manipulated by presenting informative retro-cues, whereas interference was manipulated by introducing a secondary interfering task. Mixture-model analyses revealed that retro-cues, compared to uninformative cues, improved all aspects of performance: Attention increased recall precision and decreased guessing rate and swap-errors (reporting a wrong item in memory). Similarly, performing a secondary task impaired all aspects of the VWM task. In particular, an interaction between retro-cue and secondary task interference was found primarily for swap-errors. Together these results suggest that both the quantity and quality of VWM representations are sensitive to attention cueing and interference modulations, and they highlight the role of attention in protecting the feature–location associations needed to access the correct items in memory.     

The effect of alcohol administration on human timing: a comparison of prospective timing, retrospective timing and passage of time judgements

Previous research suggests that human timing may be affected by alcohol administration. The current study aimed to expand on previous research by examining the effect of alcohol on prospective timing, retrospective timing and passage of time judgements. A blind between-subjects design was employed in which participants were either administered 0 g of alcohol per kilogramme of body weight (placebo), 0.4 g/kg (low dose) or 0.6 g/kg (high dose). Participants completed four types of temporal task; verbal estimation and temporal generalisation, a retrospective timing task and a passage of time judgement task. A high dose of alcohol resulted in overestimations of duration relative to the low dose and placebo group in the verbal estimation task. A high dose of alcohol was also associated with time passing more quickly than normal. Alcohol had no effect on retrospective judgements. The results suggest that a high dose of alcohol increases internal clock speed leading to over-estimations of duration on prospective timing tasks, and the sensation of time passing more quickly than normal. The absence of an effect of alcohol on retrospective timing supports the suggestion that retrospective judgements are not based on the output of an internal clock.     

Contrasting effects of interference and of breaks in interval timing

When a break is introduced during an interval to be timed, the interval is perceived shorter as break location is delayed. This is interpreted as a result of attention sharing between timing and monitoring the source of the break signal. Similar effects and interpretations are found in another context involving interfering tasks. Such tasks are assumed to induce transient interruptions in timing, comparable to those obtained with breaks. Break and interference conditions were contrasted in a temporal reproduction procedure with identical stimuli. Both conditions induced temporal underestimation and similar location effects. Similar trends occurred in a control condition where no processing of the interfering signal was required. The data suggest that expectancy, intentional processing, and automatic attraction of attention shorten temporal estimates.     

Attention and interference in the perception of brief visual displays

When a single target was displayed 100-200 ms after a five-item array, observers were remarkably poor at deciding whether or not the target was in the array; performance was much better when the target either preceded the array or followed it by a longer interval. This effect was independent of a number of visual display parameters, suggesting that it was not due to visual contour interaction. In addition, visual similarity did not interact with the effect, indicating that it probably did not occur during item identification either. However, when observers added one to a digit target before deciding whether it occurred in the array, the effect was substantially reduced. The results suggested a model in which abstract identity information about the target is confused with the array at certain temporal intervals. A quantitative version of this model fit the data quite well.     

Design-effects in prospective and retrospective memory for actions

There is ample evidence that memory for action phrases such as "open the bottle" is better in subject-performed tasks (SPTs), i.e., if the participants perform the actions, than in verbal tasks (VTs), if they only read the phrases or listen to them. It is less clear whether also the sole intention to perform the actions later, i.e., a prospective memory task (PT), improves memory compared with VTs. Inconsistent findings have been reported for within-subjects and between-subjects designs. The present study attempts to clarify the situation. In three experiments, better recall for SPTs than for PTs and for PTs than for VTs were observed if mixed lists were used. If pure lists were used, there was a PT effect but no SPT over PT advantage. The findings were discussed from the perspective of item-specific and relational information.     

Temporal order in memory and interval timing: an interference analysis

The effect of varying load in memory tasks performed during a time interval production was examined. In a first experiment, increasing load in memory search for temporal order affected concurrent time production more strongly than varying load in a spatial memory task of equivalent difficulty. This result suggests that timing uses some specific resources also required in processing temporal order in memory, resources that would not be used in the spatial memory task. A second experiment showed that the interference between time production and memory search involving temporal order was stronger when, during the timing task, a decision was made on the temporal position of a memory item, than when information on temporal order was retained throughout the interval to be produced. These results underscore the importance of considering the specific resources and processes involved when the interference between timing and concurrent non-temporal tasks is analyzed.     

An imperfect relationship between prospective memory and the prospective interference effect

Three experiments examined the functional relationship between the frequency of prospective responding and the prospective interference effect within the context of a task switching paradigm. Prospective responding was less frequent across the experiments when prospective cues appeared in switch blocks than when they appeared in pure blocks. The magnitude of the prospective interference effect for response time (RT) was similar for pure and switch blocks when exogenous task cuing was used, and was greater for switch blocks than for pure blocks when endogenous task cuing was used. These data reveal a dissociation between the effect of task switching on the frequency of prospective responding and the prospective interference effect, and indicate that the functional relationship between these two measures is dependent on task demands.     

The effect of perceptual distinctiveness on the prospective and retrospective components of prospective memory in young and old adults.

In two experiments, the effect of perceptual distinctiveness of cues on prospective memory performance was examined. Young and older adults completed a visual search task with embedded prospective memory instructions. On each trial, participants were asked to indicate the position of a target letter in a letter string, unless either of two letters previously identified as prospective memory cues was presented. Each prospective cue was associated with a specific response. Perceptual distinctiveness was manipulated by spatially displacing a single letter. The prospective component (successful detection of the cue) and the retrospective memory component (recalling the correct response when a cue is detected) were measured separately. Perceptual displacement of cues modulated performance of the prospective component but not the retrospective component. Young adults successfully detected a larger proportion of cues (prospective component) than older adults. However, there were minimal effects of age and no effect of cue displacement on participants' ability to recall the intention once they detected a cue (retrospective component performance). Results are discussed within the context of current theoretical models of prospective memory.     

Scale invariance in the retrieval of retrospective and prospective memories

How does memory retrieval depend on time scale? One strong hypothesis is that such retrieval is scale-invariant (i.e., invariant across different time scales). To test this hypothesis, three groups of participants were given 4 min to recall what they did yesterday, last week, or last year (retrospective memories), and 4 min to recall what they intended to do tomorrow, next week, or next year (prospective memories). In line with scale invariance, retrieval performance was indistinguishable across time scales, for both retrospective and prospective memory. An additional finding was that significantly more prospective memories were recalled than retrospective memories, confirming previous observations of the "intention-superiority effect" (Goschke & Kuhl, 1993).     

The role of executive functions in human prospective interval timing

Human timing is thought to be based on the output of an internal clock. Whilst the functioning of this clock is well documented, it is unclear which other cognitive resources may moderate timing. Brown (2006) and Rattat (2010) suggest that the central executive of working memory may be recruited during timing. However it seems likely that the fractionated executive component processes identified by Miyake et al. (2000) and Fisk and Sharp (2004) may differentially contribute to timing performance; further exploration of this was the aim of the present study. An interference paradigm was employed in which participants completed an interval production task, and tasks which have been shown to tap the four key executive component processes (shifting, inhibition, updating and access) under single and dual-task conditions. Comparison of single and dual-task performance indicated that timing always became more variable when concurrently performing a second task. Bidirectional interference only occurred between the interval production task and the memory updating task, implying that both tasks are competing for the same executive resource of updating. There was no evidence in the current study to suggest that switching, inhibition or access was involved in timing, however they may be recruited under more difficult task conditions.     

Age effects in emotional prospective memory: cue valence differentially affects the prospective and retrospective component

While first studies suggested that emotional task material may enhance prospective memory performance in young and older adults, the extent and mechanisms of this effect are under debate. The authors explored possible differential effects of cue valence on the prospective and retrospective component of prospective memory in young and older adults. Forty-five young and 41 older adults performed a prospective memory task in which emotional valence of the prospective memory cue was manipulated (positive, negative, neutral). The multinomial model of event-based prospective memory was used to analyze effects of valence and age on the two prospective memory components separately. Results revealed an interaction indicating that age differences were smaller in both emotional valence conditions. For older adults positive cues improved the prospective component, while negative cues improved the retrospective component. No main effect of valence was found for younger adults on an overt accuracy measure, but model-based analyses showed that the retrospective component was enhanced in the positive compared with the negative cue condition. The study extends the literature in demonstrating that processes underlying emotional effects on prospective memory may differ depending on valence and age.     

Visual search is guided by prospective and retrospective memory

Although there has been some controversy as to whether attention is guided by memory during visual search, recent findings have suggested that memory helps to prevent attention from needlessly reinspecting examined items. Until now, it has been assumed that some form of retrospective memory is responsible for keeping track of examined items and preventing revisitations. Alternatively, some form of prospective memory, such as strategic scanpath planning, could be responsible for guiding attention away from examined items. We used a new technique that allowed us to selectively prevent retrospective or prospective memory from contributing to search. We demonstrated that both retrospective and prospective memory guide attention during visual search.     

Relative and absolute duration judgments under prospective and retrospective paradigms

A dual-process contingency model of short duration judgment is proposed and tested. The first process, or P(t), is a timer that uses cognitive capacity to keep track of units of time. If capacity is directed toward other tasks, P(t) will record fewer units and produce lower time judgments than when capacity is not directed toward other tasks. This timing process is most likely to affect performance when people know in advance (prospective judgments) that time judgments will be required and when absolute, rather than relative, judgments are made. The second process, or P(m), which is used for retrospective and relative judgments, judges duration on the basis of the number of remembered high priority events (HPEs) occurring during the interval. When this process is used, time judgments increase with the amount of HPEs that can be retrieved at the moment of judgment. Two experiments are reported. Tactual stimuli were presented, and nontemporal information processing load (simple or complex stimuli), type of judgment (absolute or relative), and judgment paradigm (prospective or retrospective)were manipulated. The results obtained support the proposed dual-process contingency model.     

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.