The scope and precision of specific temporal expectancy: evidence from a variable foreperiod paradigm

Recent evidence from choice response time experiments with variable foreperiods (FPs) has shown that temporal expectancy can be event specific. When a certain target appears particularly frequent after one certain FP, participants tend to expect that target after that FP. This typically results in best performance for that target when it appears after that FP. In the present study, we investigated how temporally precise event-specific temporal expectancy is, and in which range of FPs it can be found. Two target stimuli were asymmetrically distributed over two "peak-FPs" and were equally distributed over 13 additional FPs. Event-specific expectancies were found for peak-FP pairs of 500/1,100?ms and 300/500?ms. Furthermore, the event expectancies generalized to a wide range of nonpeak FPs surrounding the peak FPs.     

Variable foreperiods and temporal discrimination

Temporal judgements are often accounted for by a single-clock hypothesis. The output of such a clock is reported to depend on the allocation of attention. In the present series of experiments, the influence of attention on temporal information processing is investigated by systematic variations of the period preceding brief empty intervals to be judged. Two indicators of timing performance, temporal sensitivity, reflecting discrimination performance, and perceived duration served as dependent variables. Foreperiods ranged from 0.3 to 0.6 s in Experiments 1 to 4. When the foreperiod varied randomly from trial to trial, perceived duration was longer with increasing length of foreperiod (Experiments 1 and 3 with brief auditory markers and Experiment 4 with brief visual markers), an effect that disappeared with no trial-to-trial variations (Experiment 2). Longer foreperiods also enhanced performance on temporal discrimination of auditory empty intervals with a base duration of 100 ms (Experiments 1 and 5), whereas discrimination performance was unaffected for auditory intervals with a base duration of 500 ms (Experiment 3). The variable-foreperiod effect on perceived duration also held when foreperiods ranged from 0.6 to 1.5 s (Experiments 5-7). Findings suggest that foreperiods appear to effectively modulate attention mechanisms necessary for temporal information processing. However, alternative explanations such as assimilation or compatibility effects cannot be totally discarded.     

Response specific temporal expectancy: Evidence from a variable foreperiod paradigm

When a stimulus-response event is frequently paired with a specific foreperiod, response performance for this event is improved after this foreperiod. This phenomenon is referred to as specific temporal expectancy. In four experiments, we investigated whether stimulus- or response-related processing benefits from specific temporal expectancy. In a speeded choice reaction task, different features of the imperative stimuli were frequently paired with foreperiods in such a way that only in some experiments were the responses also frequently paired with foreperiods. Participants revealed evidence for specific temporal expectancy when responses were frequently paired with foreperiods, but not when only the stimuli were frequently paired with foreperiods. We concluded that specific temporal expectancy affects response-related processing.     

Temporal preparation improves temporal resolution: Evidence from constant foreperiods

Recent research shows that temporal preparation within a constant foreperiod design improves the spatial resolution of visual perception. The present experiments were designed to investigate whether similar benefits of temporal preparation can be observed in a task that requires high temporal resolution. In three experiments, we assessed the effect of temporal preparation on temporal order judgments (TOJs). In Experiment 1, short foreperiods facilitated TOJ for two spatially adjacent dots. This finding was replicated in Experiment 2, in which the temporal order of two spatially overlapping stimuli (“+” and “x”) had to be discriminated. Experiment 3 investigated the time course of temporal preparation by extending these findings to a wide range of different foreperiod durations. The present findings corroborate recent evidence for a perceptual locus of temporal preparation. Most importantly, they show that temporal preparation within a constant foreperiod design improves the temporal resolution of visual perception, independently of whether TOJ requires a decision about the location or about the identity of the target stimuli.     

Timing a week later: The role of long-term memory in temporal preparation

Temporal preparation has been investigated extensively by manipulating the foreperiod, the interval between a warning stimulus and target stimulus requiring a speeded response. Although such research has revealed many effects of both the duration and distribution of foreperiods on reaction times, the underlying cognitive mechanism is still largely unknown. Here, we test a recent proposal that temporal preparation is driven by the retrieval of memory traces of past experiences from long-term memory rather than by knowledge about upcoming events. Two groups of participants received different foreperiod distributions in an acquisition phase, which was followed a week later by a transfer phase, in which both groups received the same distribution of foreperiods. We found that the effects of the different foreperiod distributions presented in the acquisition phase were still apparent a week later during the transfer phase, as the reaction time patterns of both groups reflected the old distributions. This occurred even though both groups were provided with full information about the change in the distribution of foreperiods at the start of the transfer phase. These findings provide compelling evidence that long-term memory plays an important role in temporal preparation.     

Being prepared on time: on the importance of the previous foreperiod to current preparation, as reflected in speed, force and preparation-related brain potentials

How do participants adapt to temporal variation of preparatory foreperiods? For reaction times, specific sequential effects have been observed. Responses become slower when the foreperiod is shorter on the current than on the previous trial. If this effect is due to changes in motor activation, it should also be visible in force of responses and in EEG measures of motor preparation, the contingent negative variation (CNV) and the lateralized readiness potential (LRP). These hypotheses were tested in a two-choice reaction task, with targets occurring 500, 1500, or 2500 ms after an acoustic warning signal. The reaction time results showed the expected pattern and were accompanied by similar effects on a fronto-central CNV and the LRP. In contrast, the increase of response force with brief current foreperiods did not depend on previous foreperiods. Thus, EEG measures confirm that sequential effects on RT are at least partially due to changes in motor activation originating from previous trials. Effects found on response force may be related to general response readiness rather than activation of motor-hand areas, which may explain the absence of a sequential effect on force in the current experiment.     

Burnout and the Fine‐Tuning of Cognitive Resources

We examined the performance in a constant foreperiod task in two samples screened for either high or low scores on the core burnout dimension emotional exhaustion. In line with our expectations, participants scoring high on emotional exhaustion exhibited a specific deficit with respect to maintaining a high level of response readiness at longer foreperiods. This demonstration of a modulation of constant foreperiod performance by burnout adds to the growing body of evidence suggesting that exhaustion is related to deficits in basic cognitive mechanisms underlying the fine‐tuning of cognitive resources according to task demands. Copyright © 2014 John Wiley & Sons, Ltd.     

Functional dissociations in temporal preparation: Evidence from dual-task performance

Implicit preparation over time is a complex cognitive capacity important to optimize behavioral responses to a target occurring after a temporal interval, the so-called foreperiod (FP). If the FP occurs randomly and with the same a priori probability, shorter response times are usually observed with longer FPs than with shorter ones (FP effect). Moreover, responses are slower when the preceding FP was longer than the current one (sequential effects). It is still a matter of debate how different processes influence these temporal preparation phenomena. The present study used a dual-task procedure to understand how different processes, along the automatic-controlled continuum, may contribute to these temporal preparation phenomena. Dual-task demands were manipulated in two experiments using a subtraction task during the FP. This secondary task was administered in blocks (Experiment 1) or was embedded together with a baseline single-task in the same experimental session (Experiment 2). The results consistently showed that the size of the FP effect, but not that of sequential effects, is sensitive to dual-task manipulations. This functional dissociation unveils the multi-faceted nature of implicit temporal preparation: while the FP effect is due to a controlled, resource-consuming preparatory mechanism, a more automatic mechanism underlies sequential effects.     

Developmental dissociations of preparation over time: deconstructing the variable foreperiod phenomena

In a variable foreperiod (FP) paradigm, reaction times (RTs) decrease as a function of FP on trial n (FP effect) but increase with FP on trial n - 1 (sequential effects). These phenomena have traditionally been ascribed to different strategic preparation processes. According to an alternative explanation, common conditioning laws underlie both effects. The present study aims to disentangle these opposite views using a developmental perspective. In Experiment 1A, 4- to 11-year-old children and a control group of adults performed a simple RT task with variable FPs (1, 3, and 5 s). Furthermore, 12 4- to 5-year-old children were retested after 14 months (Experiment 1B). In Experiment 2, a narrower pool of participants (4, 5, and 6 years old) performed a variable FP paradigm with different FPs (1, 2, and 3 s). The results consistently suggest different ontogenetic time courses for the two effects: The sequential effects are already present in the youngest group (4-5 years old), whereas the FP effect appears gradually some years later. These findings are not fully compatible with previous views. A dual-process account is proposed to explain the data.     

Conflict adaptation in time: Foreperiods as contextual cues for attentional adjustment

Interference evoked by distractor stimulus information, such as flankers in the Eriksen task, is reduced when the proportion of conflicting stimuli is increased. This modulation is sensitive to contextual cues such as stimulus location or color, suggesting attentional adjustment to conflict contingencies on the basis of context information. In the present study, we explored whether conflict adjustment is modulated by temporal variation of conflict likelihood. To this end, we associated low and high proportions of conflict stimuli with foreperiods of different lengths. Flanker interference was higher with foreperiods associated with low conflict proportions, suggesting that participants use the foreperiod as a contextual cue for attentional adjustment. We conjecture that participants initially adopt the strategy useful for conflict contingencies associated with short foreperiods, and then readjust during the trial, in the absence of any additional exogenous cue, when the imperative stimulus has not occurred during a certain time interval.     

Rhythmic context modulates foreperiod effects

Two experiments examined hypotheses about the roles of probabilistic uncertainty and rhythmic context on attentional preparation as reflected by choice response times (RTs) to the final tone of auditory sequences. Nonisochronous sequences with tone timings either arranged metrically or scrambled were linked with one of three different sequence-final time intervals, or foreperiods (FPs), which varied randomly from trial to trial. Two primary results emerged. First, RTs were faster to target tones ending metrical rhythms than to targets ending scrambled rhythms. Second, metrical contexts elicited RTs that increased with FP duration, whereas scrambled contexts elicited RTs that often decreased with FP duration, despite equivalent variability of time intervals in metrical and scrambled contexts. The results suggest that time relations implied by metrical rhythms systematically modulate preparatory responses to sequence-final FPs.     

The adaptive character of the attentional system: statistical sensitivity in a target localization task

A localization task required participants to indicate which of 4 locations contained a briefly displayed target. Most displays also contained a distractor that was not equally probable in these locations, affecting performance dramatically. Responses were faster when a display had no distractor and almost as fast when the distractor was in its frequent location. Conversely, responses were slower when targets appeared in frequent-distractor locations, even thou targets were equally likely in each location. Negative-priming effects were reliably smaller when targets followed distractors in the frequent-distractor location compared to the rare-distractor location, challenging the episodic-retrieval account Experiment 2 added a 5th location that rarely displayed distractors and never targets, yet responses slowed most when distractors appeared there. The results confirmed that the attentional system is sensitive to first- and higher-order statistical patterns and can make short- and long-term adjustments in preferences based on prior history of inspecting unsuccessful locations.     

The modality shift effect and the effectiveness of warning signals in different modalities

Which is better, a visual or an auditory warning signal? Initial findings suggested that an auditory signal was more effective, speeding reaction to a target more than a visual warning signal, particularly at brief foreperiods [Bertelson, P., & Tisseyre, F. (1969). The time-course of preparation: confirmatory results with visual and auditory warning signals. Acta Psychologica, 30. In W.G. Koster (Ed.), Attention and Performance II (pp. 145-154); Davis, R., & Green, F. A. (1969). Intersensory differences in the effect of warning signals on reaction time. Acta Psychologica, 30. In W.G. Koster (Ed.), Attention and Performance II (pp. 155-167)]. This led to the hypothesis that an auditory signal is more alerting than a visual warning signal [Sanders, A. F. (1975). The foreperiod effect revisited. Quarterly Journal of Experimental Psychology, 27, 591-598; Posner, M. I., Nissen, M. J., & Klein, R. M. (1976). Visual dominance: an information-processing account of its origins and significance. Psychological Review, 83, 157-171]. Recently [Turatto, M., Benso, F., Galfano, G., & Umilta, C. (2002). Nonspatial attentional shifts between audition and vision. Journal of Experimental Psychology: Human Perception and Performance, 28, 628-639] found no evidence for an auditory warning signal advantage and showed that at brief foreperiods a signal in the same modality as the target facilitated responding more than a signal in a different modality. They accounted for this result in terms of the modality shift effect, with the signal exogenously recruiting attention to its modality, and thereby facilitating responding to targets arriving in the modality to which attention had been recruited. The present study conducted six experiments to understand the cause of these conflicting findings. The results suggest that an auditory warning signal is not more effective than a visual warning signal. Previous reports of an auditory superiority appear to have been caused by using different locations for the visual warning signal and visual target, resulting in the target arriving at an unattended location when the foreperiod was brief. Turatto et al.'s results were replicated with a modality shift effect at brief foreperiods. However, it is also suggested that previous measures of the modality shift effect may still have been confounded by a location cuing effect.     

Dissociative patterns of foreperiod effects in temporal discrimination and reaction time tasks

This study examined whether the process of temporal preparation for a target stimulus is the same regardless of the task required by the target stimulus. To this end, the same variable-foreperiod design was used in a temporal discrimination task (Experiment 1) and a reaction time task (Experiment 2). In Experiment 1, both temporal sensitivity and perceived duration increased as a function of foreperiod, whereas in Experiment 2, foreperiod did not influence reaction time. Furthermore, both temporal sensitivity and perceived duration revealed an asymmetric sequential effect of foreperiod, but the pattern of this effect was opposite to the pattern observed in the reaction time task. Together these dissociative patterns of foreperiod effects suggest that the mechanism of temporal preparation depends on the task required by the target stimulus.     

Dissociative patterns of foreperiod effects in temporal discrimination and reaction time tasks

This study examined whether the process of temporal preparation for a target stimulus is the same regardless of the task required by the target stimulus. To this end, the same variable-foreperiod design was used in a temporal discrimination task (Experiment 1) and a reaction time task (Experiment 2). In Experiment 1, both temporal sensitivity and perceived duration increased as a function of foreperiod, whereas in Experiment 2, foreperiod did not influence reaction time. Furthermore, both temporal sensitivity and perceived duration revealed an asymmetric sequential effect of foreperiod, but the pattern of this effect was opposite to the pattern observed in the reaction time task. Together these dissociative patterns of foreperiod effects suggest that the mechanism of temporal preparation depends on the task required by the target stimulus.     

Incidental and intentional visual memory: What memories are and are not affected by encoding tasks?

Prior research into the impact of encoding tasks on visual memory (Castelhano & Henderson, 2005) indicated that incidental and intentional encoding tasks led to similar memory performance. The current study investigated whether different encoding tasks impacted visual memories equally for all types of objects in a conjunction search (e.g., targets, colour distractors, object category distractors, or distractors unrelated to the target). In sequences of pictures, participants searched for prespecified targets (e.g., green apple; Experiment 1), memorized all objects (Experiment 2), searched for specified targets while memorizing all objects (Experiment 3), searched for postidentified targets (Experiment 4), or memorized all objects with one object prespecified (Experiment 5). Encoding task significantly improved visual memory for targets and led to worse memory for unrelated distractors, but did not influence visual memory of distractors that were related to the target's colour or object category. The differential influence of encoding task indicates that the relative importance of the object both positively and negatively influences the memory retained.     

Distractor clustering enhances detection speed and accuracy during selective listening

The effects of distractor clustering on target detection were examined in two experiments in which subjects attended to binaural tone bursts of one frequency while ignoring distracting tones of two competing frequencies. The subjects pressed a button in response to occasional target tones of longer duration (Experiment 1) or increased loudness (Experiment 2). In evenly spaced conditions, attended and distractor frequencies differed by 6 and 12 semitones, respectively (e.g., 2096-Hz targets vs. 1482- and 1048-Hz distractors). In clustered conditions, distractor frequencies were grouped; attended tones differed from the distractors by 6 and 7 semitones, respectively (e.g., 2096-Hz targets vs. 1482- and 1400-Hz distractors). The tones were presented in randomized sequences at fixed or random stimulus onset asynchronies (SOAs). In both experiments, clustering of the unattended frequencies improved the detectability of targets and speeded target reaction times, Similar effects were found at fixed and variable SO As. Results from the analysis of stimulus sequence suggest that clustering improved performance primarily by reducing the interference caused by distractors that immediately preceded the target.     

On the inability to ignore touch when responding to vision in the crossmodal congruency task

We investigated the extent to which people can selectively ignore distracting vibrotactile information when performing a visual task. In Experiment 1, participants made speeded elevation discrimination responses (up vs. down) to a series of visual targets presented from one of two eccentricities on either side of central fixation, while simultaneously trying to ignore task-irrelevant vibrotactile distractors presented independently to the finger (up) vs. thumb (down) of either hand. Participants responded significantly more slowly, and somewhat less accurately, when the elevation of the vibrotactile distractor was incongruent with that of the visual target than when they were presented from the same (i.e., congruent) elevation. This crossmodal congruency effect was significantly larger when the visual and tactile stimuli appeared on the same side of space than when they appeared on different sides, although the relative eccentricity of the two stimuli within the hemifield (i.e., same vs. different) had little effect on performance. In Experiment 2, participants who crossed their hands over the midline showed a very different pattern of crossmodal congruency effects to participants who adopted an uncrossed hands posture. Our results suggest that both the relative external location and the initial hemispheric projection of the target and distractor stimuli contribute jointly to determining the magnitude of the crossmodal congruency effect when participants have to respond to vision and ignore touch.     

Control strategies when intercepting slowly moving targets

In 3 experiments, the authors investigated and described how individuals control manual interceptive movements to slowly moving targets. Participants (N = 8 in each experiment) used a computer mouse and a graphics tablet assembly to manually intercept targets moving across a computer screen toward a marked target zone. They moved the cursor so that it would arrive in the target zone simultaneously with the target. In Experiment 1, there was a range of target velocities, including some very slow targets. In Experiment 2, there were 2 movement distance conditions. Participants moved the cursor either the same distance as the target or twice as far. For both experiments, hand speed was found to be related to target speed, even for the very slowly moving targets and when the target-to-cursor distance ratios were altered, suggesting that participants may have used a strategy similar to tracking. To test that notion, in Experiment 3, the authors added a tracking task in which the participants tracked the target cursor into the target zone. Longer time was spent planning the interception movements; however, there was a longer time in deceleration for the tracking movements, suggesting that more visually guided trajectory updates were made in that condition. Thus, although participants scaled their interception movements to the cursor speed, they were using a different strategy than they used in tracking. It is proposed that during target interception, anticipatory mechanisms are used rather than the visual feedback mechanism used when tracking and when pointing to stationary targets.